server oracle® database gateway for sql user's guidethis manual describes the oracle database...

Oracle® Database Gateway for SQLServerUser's Guide

20cF19308-01September 2019

Oracle Database Gateway for SQL Server User's Guide, 20c

F19308-01

Copyright © 2002, 2019, Oracle and/or its affiliates. All rights reserved.

Primary Author: Rhonda Day

Contributing Authors: Vira Goorah, Juan Pablo Ahues-Vasquez, Peter Castro, Charles Benet, Peter Wong,Govind Lakkoju

This software and related documentation are provided under a license agreement containing restrictions onuse and disclosure and are protected by intellectual property laws. Except as expressly permitted in yourlicense agreement or allowed by law, you may not use, copy, reproduce, translate, broadcast, modify,license, transmit, distribute, exhibit, perform, publish, or display any part, in any form, or by any means.Reverse engineering, disassembly, or decompilation of this software, unless required by law forinteroperability, is prohibited.

The information contained herein is subject to change without notice and is not warranted to be error-free. Ifyou find any errors, please report them to us in writing.

If this is software or related documentation that is delivered to the U.S. Government or anyone licensing it onbehalf of the U.S. Government, then the following notice is applicable:

U.S. GOVERNMENT END USERS: Oracle programs, including any operating system, integrated software,any programs installed on the hardware, and/or documentation, delivered to U.S. Government end users are"commercial computer software" pursuant to the applicable Federal Acquisition Regulation and agency-specific supplemental regulations. As such, use, duplication, disclosure, modification, and adaptation of theprograms, including any operating system, integrated software, any programs installed on the hardware,and/or documentation, shall be subject to license terms and license restrictions applicable to the programs.No other rights are granted to the U.S. Government.

This software or hardware is developed for general use in a variety of information management applications.It is not developed or intended for use in any inherently dangerous applications, including applications thatmay create a risk of personal injury. If you use this software or hardware in dangerous applications, then youshall be responsible to take all appropriate fail-safe, backup, redundancy, and other measures to ensure itssafe use. Oracle Corporation and its affiliates disclaim any liability for any damages caused by use of thissoftware or hardware in dangerous applications.

Oracle and Java are registered trademarks of Oracle and/or its affiliates. Other names may be trademarks oftheir respective owners.

Intel and Intel Xeon are trademarks or registered trademarks of Intel Corporation. All SPARC trademarks areused under license and are trademarks or registered trademarks of SPARC International, Inc. AMD, Opteron,the AMD logo, and the AMD Opteron logo are trademarks or registered trademarks of Advanced MicroDevices. UNIX is a registered trademark of The Open Group.

This software or hardware and documentation may provide access to or information about content, products,and services from third parties. Oracle Corporation and its affiliates are not responsible for and expresslydisclaim all warranties of any kind with respect to third-party content, products, and services unless otherwiseset forth in an applicable agreement between you and Oracle. Oracle Corporation and its affiliates will not beresponsible for any loss, costs, or damages incurred due to your access to or use of third-party content,products, or services, except as set forth in an applicable agreement between you and Oracle.

Contents

Preface

Audience xi

Documentation Accessibility xi

Related Documentation xii

Conventions xii

1 Introduction to the Oracle Database Gateway for SQL Server

Overview of Oracle Database Gateways 1-1

About Heterogeneous Services Technology 1-1

About Oracle Database Gateway for SQL Server 1-2

2 SQL Server Gateway Features and Restriction

Remote Insert Rowsource 2-1

Using the Pass-Through Feature 2-2

Executing Stored Procedures and Functions 2-3

CHAR Semantics 2-3

Multi-byte Character Sets Ratio Suppression 2-3

IPv6 Support 2-3

Gateway Session IDLE Timeout 2-4

Remote User-defined Function Support 2-4

Return Values and Stored Procedures 2-4

Result Sets and Stored Procedures 2-5

OCI Program Fetching from Result Sets in Sequential Mode 2-6

PL/SQL Program Fetching from Result Sets in Sequential Mode 2-7

Database Compatibility Issues for SQL Server 2-8

Implicit Transactions (Chained Mode) 2-9

Column Definitions 2-9

Naming Rules 2-9

Rules for Naming Objects 2-9

Case Sensitivity 2-9

Data Types 2-10

iii

Binary Literal Notation 2-10

Bind Variables With LONG Columns 2-10

Data Type Conversion 2-11

Queries 2-11

Row Selection 2-11

Empty Strings 2-11

Empty Bind Variables 2-12

Locking 2-12

Known Restrictions 2-12

Multiple Open Statements 2-13

Transactional Integrity 2-13

Transaction Capability 2-13

COMMIT or ROLLBACK in PL/SQL Cursor Loops Closes Open Cursors 2-13

Stored Procedures 2-14

Pass-Through Feature 2-14

DDL Statements 2-14

SQL Syntax 2-15

WHERE CURRENT OF Clause 2-15

CONNECT BY Clause 2-15

Functions in Subqueries 2-16

Parameters in Subqueries 2-16

Data Dictionary Table and Views in UPDATE Statement 2-16

ROWID 2-16

TO_DATE 2-16

EXPLAIN PLAN Statement 2-16

Functions 2-16

SQL*Plus COPY Command with Lowercase Table Names 2-16

Database Links 2-16

Known Problems 2-17

Encrypted Format Login 2-17

Date Arithmetic 2-17

SQL Server IMAGE, TEXT and NTEXT Data Types 2-17

String Functions 2-18

Schema Names and PL/SQL 2-18

Data Dictionary Views and PL/SQL 2-18

Stored Procedures 2-18

3 Case Studies

Case Descriptions 3-1

Installation Media Contents 3-1

iv

Demonstration Files 3-2

Demonstration Requirements 3-2

Creating Demonstration Tables 3-2

Demonstration Table Definitions 3-3

Demonstration Table Contents 3-4

Case 1: Simple Queries 3-5

Case 2: A More Complex Query 3-5

Case 3: Joining SQL Server Tables 3-5

Case 4: Write Capabilities 3-5

DELETE Statement 3-5

UPDATE Statement 3-5

INSERT Statement 3-6

Case 5: Data Dictionary Query 3-6

Case 6: The Pass-Through Feature 3-6

UPDATE Statement 3-6

SELECT Statement 3-6

Case 7: Executing Stored Procedures 3-6

A Data Type Conversion

B Supported SQL Syntax and Functions

Supported SQL Statements B-1

DELETE B-1

INSERT B-1

SELECT B-2

UPDATE B-2

Oracle Functions B-2

Functions Not Supported by SQL Server B-2

Functions Supported by SQL Server B-2

Arithmetic Operators B-3

Comparison Operators B-3

Pattern Matching B-3

Group Functions B-3

String Functions B-4

Other Functions B-4

Functions Supported by the Gateway B-5

C Data Dictionary

Data Dictionary Support C-1

v

SQL Server System Tables C-1

Accessing the Gateway Data Dictionary C-1

Direct Queries to SQL Server Tables C-2

Supported Views and Tables C-2

Data Dictionary Mapping C-3

Default Column Values C-4

Gateway Data Dictionary Descriptions C-4

ALL_CATALOG C-5

ALL_COL_COMMENTS C-5

ALL_CONS_COLUMNS C-5

ALL_CONSTRAINTS C-6

ALL_IND_COLUMNS C-6

ALL_INDEXES C-7

ALL_OBJECTS C-8

ALL_TAB_COLUMNS C-9

ALL_TAB_COMMENTS C-10

ALL_TABLES C-10

ALL_USERS C-12

ALL_VIEWS C-12

DBA_CATALOG C-12

DBA_COL_COMMENTS C-13

DBA_OBJECTS C-13

DBA_TAB_COLUMNS C-13

DBA_TAB_COMMENTS C-14

DBA_TABLES C-15

DICT_COLUMNS C-16

DICTIONARY C-16

DUAL C-16

TABLE_PRIVILEGES C-17

USER_CATALOG C-17

USER_COL_COMMENTS C-17

USER_CONS_COLUMNS C-18

USER_CONSTRAINTS C-18

USER_IND_COLUMNS C-19

USER_INDEXES C-19

USER_OBJECTS C-21

USER_TAB_COLUMNS C-21

USER_TAB_COMMENTS C-22

USER_TABLES C-22

USER_USERS C-24

vi

USER_VIEWS C-24

D Initialization Parameters

Initialization Parameter File Syntax D-1

Oracle Database Gateway for SQL Server Initialization Parameters D-2

HS_CALL_NAME D-3

HS_DB_DOMAIN D-4

HS_DB_INTERNAL_NAME D-4

HS_DB_NAME D-4

HS_DESCRIBE_CACHE_HWM D-5

HS_LANGUAGE D-5

Character Sets D-5

Language D-6

Territory D-6

HS_LONG_PIECE_TRANSFER_SIZE D-6

HS_OPEN_CURSORS D-7

HS_RPC_FETCH_REBLOCKING D-7

HS_RPC_FETCH_SIZE D-7

HS_TIME_ZONE D-8

HS_FDS_ENCRYPT_SESSION D-8

HS_FDS_TRANSACTION_ISOLATION D-8

HS_FDS_TRUSTSTORE_FILE D-9

HS_FDS_TRUSTSTORE_PASSWORD D-9

HS_FDS_VALIDATE_SERVER_CERT D-9

HS_TRANSACTION_MODEL D-10

IFILE D-10

HS_FDS_TIMESTAMP_MAPPING D-11

HS_FDS_DATE_MAPPING D-11

HS_FDS_CONNECT_INFO D-11

HS_FDS_PROC_IS_FUNC D-12

HS_FDS_RECOVERY_ACCOUNT D-13

HS_FDS_RECOVERY_PWD D-13

HS_FDS_REPORT_REAL_AS_DOUBLE D-13

HS_FDS_RESULTSET_SUPPORT D-13

HS_FDS_TRACE_LEVEL D-14

HS_FDS_TRANSACTION_LOG D-14

HS_FDS_FETCH_ROWS D-14

HS_IDLE_TIMEOUT D-15

HS_NLS_LENGTH_SEMANTICS D-15

HS_KEEP_REMOTE_COLUMN_SIZE D-15

vii

HS_FDS_REMOTE_DB_CHARSET D-16

HS_FDS_SUPPORT_STATISTICS D-16

HS_FDS_RSET_RETURN_ROWCOUNT D-16

HS_FDS_SQLLEN_INTERPRETATION D-17

HS_FDS_ARRAY_EXEC D-17

Index

viii

List of Tables

A-1 Data Type Mapping and Restrictions A-1

C-1 Oracle Data Dictionary View Names and SQL Server Equivalents C-3

C-2 ALL_CATALOG C-5

C-3 ALL_COL_COMMENTS C-5

C-4 ALL_CONS_COLUMNS C-5

C-5 ALL_CONSTRAINTS C-6

C-6 ALL_IND_COLUMNS C-6

C-7 ALL_INDEXES C-7

C-8 ALL_OBJECTS C-8

C-9 ALL_TAB_COLUMNS C-9

C-10 ALL_TAB_COMMENTS C-10

C-11 ALL_TABLES C-10

C-12 ALL_USERS C-12

C-13 ALL_VIEWS C-12

C-14 DBA_CATALOG C-12

C-15 DBA_COL_COMMENTS C-13

C-16 DBA_OBJECTS C-13

C-17 DBA_TAB_COLUMNS C-13

C-18 DBA_TAB_COMMENTS C-14

C-19 DBA_TABLES C-15

C-20 DICT_COLUMNS C-16

C-21 DICTIONARY C-16

C-22 DUAL C-16

C-23 TABLE_PRIVILEGES C-17

C-24 USER_CATALOG C-17

C-25 USER_COL_COMMENTS C-17

C-26 USER_CONS_COLUMNS C-18

C-27 USER_CONSTRAINTS C-18

C-28 USER_IND_COLUMNS C-19

C-29 USER_INDEXES C-19

C-30 USER_OBJECTS C-21

C-31 USER_TAB_COLUMNS C-21

C-32 USER_TAB_COMMENTS C-22

C-33 USER_TABLES C-22

C-34 USER_USERS C-24

ix

C-35 USER_VIEWS C-24

x

Preface

This manual describes the Oracle Database Gateway for SQL Server, which enablesOracle client applications to access SQL Server data through Structured QueryLanguage (SQL). The gateway, with the Oracle database, creates the appearance thatall data resides on a local Oracle database, even though the data can be widelydistributed.

This preface covers the following topics:

• Audience

• Documentation Accessibility

• Related Documentation

• Conventions

AudienceThis manual is intended for Oracle database administrators who perform the followingtasks:

• Installing and configuring the Oracle Database Gateway for SQL Server

• Diagnosing gateway errors

• Using the gateway to access SQL Server data

Note:

You should understand the fundamentals of Oracle Database Gatewaysand the Microsoft Windows operating system before using this guide toinstall or administer the gateway.

Documentation AccessibilityFor information about Oracle's commitment to accessibility, visit the OracleAccessibility Program website at http://www.oracle.com/pls/topic/lookup?ctx=acc&id=docacc.

Access to Oracle Support

Oracle customers that have purchased support have access to electronic supportthrough My Oracle Support. For information, visit http://www.oracle.com/pls/topic/lookup?ctx=acc&id=info or visit http://www.oracle.com/pls/topic/lookup?ctx=acc&id=trsif you are hearing impaired.

xi

http://www.oracle.com/pls/topic/lookup?ctx=acc&id=docacc

http://www.oracle.com/pls/topic/lookup?ctx=acc&id=docacc

http://www.oracle.com/pls/topic/lookup?ctx=acc&id=info

http://www.oracle.com/pls/topic/lookup?ctx=acc&id=info

http://www.oracle.com/pls/topic/lookup?ctx=acc&id=trs

Related DocumentationFor more information, see the following documents:

• Oracle Database New Features Guide

• Oracle Call Interface Programmer's Guide

• Oracle Database Administrator's Guide

• Oracle Database Development Guide

• Oracle Database Concepts

• Oracle Database Performance Tuning Guide

• Oracle Database Error Messages

• Oracle Database Globalization Support Guide

• Oracle Database Reference

• Oracle Database SQL Language Reference

• Oracle Database Net Services Administrator's Guide

• SQL*Plus User's Guide and Reference

• Oracle Database Heterogeneous Connectivity User's Guide

• Oracle Database 2 Day DBA

• Oracle Database Security Guide

Many of the examples in this book use the sample schemas of the seed database,which is installed by default when you install Oracle. Refer to Oracle Database SampleSchemas for information on how these schemas were created and how you can usethem yourself.

Printed documentation is available for sale in the Oracle Store at

https://shop.oracle.com/

ConventionsThe following text conventions are used in this document:

Convention Meaning

boldface Boldface type indicates graphical user interface elements associatedwith an action, or terms defined in text or the glossary.

italic Italic type indicates book titles, emphasis, or placeholder variables forwhich you supply particular values.

monospace Monospace type indicates commands within a paragraph, URLs, codein examples, text that appears on the screen, or text that you enter.

Preface

xii

https://shop.oracle.com/

1Introduction to the Oracle DatabaseGateway for SQL Server

Oracle Database Gateways provide the ability to transparently access data residing ina non-Oracle system from an Oracle environment. The following sections briefly coverHeterogeneous Services, the technology that the Oracle Database Gateway for SQLServer is based on.

To get a good understanding of generic gateway technology, Heterogeneous Services,and how Oracle Database Gateways fit in the picture, reading Oracle DatabaseHeterogeneous Connectivity User's Guide first is highly recommended.

Topics:

• Overview of Oracle Database Gateways

• About Heterogeneous Services Technology

• Oracle Database Gateways

Overview of Oracle Database GatewaysHeterogeneous data access is a problem that affects a lot of companies. A lot ofcompanies run several different database systems. Each of these systems stores dataand has a set of applications that run against it. Consolidation of this data in onedatabase system is often hard-in large part because many of the applications that runagainst one database may not have an equivalent that runs against another. Until suchtime as migration to one consolidated database system is made feasible, it isnecessary for the various heterogeneous database systems to interoperate.

Oracle Database Gateways provide the ability to transparently access data residing ina non-Oracle system from an Oracle environment. This transparency eliminates theneed for application developers to customize their applications to access data fromdifferent non-Oracle systems, thus decreasing development efforts and increasing themobility of the application. Applications can be developed using a consistent Oracleinterface for both Oracle and SQL Server.

Gateway technology is composed of two parts: a component that has the generictechnology to connect to a non-Oracle system, which is common to all the non-Oraclesystems, called Heterogeneous Services, and a component that is specific to the non-Oracle system that the gateway connects to. Heterogeneous Services, in conjunctionwith the Oracle Database Gateway agent, enables transparent access to non-Oraclesystems from an Oracle environment.

About Heterogeneous Services TechnologyHeterogeneous Services provides the generic technology for connecting to non-Oraclesystems. As an integrated component of the database, Heterogeneous Services canexploit features of the database, such as the powerful SQL parsing and distributedoptimization capabilities.

1-1

Heterogeneous Services extend the Oracle SQL engine to recognize the SQL andprocedural capabilities of the remote non-Oracle system and the mappings required toobtain necessary data dictionary information. Heterogeneous Services provides twotypes of translations: the ability to translate Oracle SQL into the proper dialect of thenon-Oracle system as well as data dictionary translations that displays the metadata ofthe non-Oracle system in the local format. For situations where no translations areavailable, native SQL can be issued to the non-Oracle system using the pass-throughfeature of Heterogeneous Services.

Heterogeneous Services also maintains the transaction coordination between Oracleand the remote non-Oracle system, such as providing the two-phase commit protocolto ensure distributed transaction integrity, even for non-Oracle systems that do notnatively support two-phase commit.

See Also:

Oracle Database Heterogeneous Connectivity User's Guide for moreinformation about Heterogeneous Services.

About Oracle Database Gateway for SQL ServerThe capabilities, SQL mappings, data type conversions, and interface to the remotenon-Oracle system are contained in the gateway. The gateway interacts withHeterogeneous Services to provide the transparent connectivity between Oracle andnon-Oracle systems.

The gateway can be installed on any machine independent of the Oracle or non-Oracle database. It can be the same machine as the Oracle database or on the samemachine as the SQL Server database or on a third machine as a standalone.

Chapter 1About Oracle Database Gateway for SQL Server

1-2

2SQL Server Gateway Features andRestriction

After the gateway is installed and configured, you can use the gateway to access SQLServer data, pass SQL Server commands from applications to the SQL Serverdatabase, perform distributed queries, and copy data.

Topics:

• Remote Insert Rowsource

• Using the Pass-Through Feature

• Executing Stored Procedures and Functions

• CHAR Semantics

• Multi-byte Character Sets Ratio Suppression

• IPv6 Support

• Remote User-defined Function Support

• Database Compatibility Issues for SQL Server

• Known Restrictions

• Known Problems

Remote Insert RowsourceA remote insert rowsource feature allows remote insert requiring local Oracle data towork through the Oracle database and Oracle Database Gateway. This functionalityrequires that the Oracle database and the Oracle Database Gateway to be version12.2 or later.

By Oracle Database design, some distributed statement must be executed at thedatabase link site. But in certain circumstances, there is data needed to execute thesequeries that must be fetched from the originating Oracle Database. Underhomogeneous connections, the remote Oracle database would call back the sourceOracle database for such data. But in heterogeneous connections, this is not viable,because this means that the Foreign Data Store would have to query call backfunctions, or data, that can only be provided by the Oracle instance that issued thequery. In general, these kinds of statements are not something that can be supportedthrough the Oracle Database Gateway.

The following categories of SQL statements results in a callback:

• Any DML with a sub-select, which refers to a table in Oracle database.

• Any DELETE, INSERT, UPDATE or "SELECT... FOR UPDATE..." SQL statementcontaining SQL functions or statements that needs to be executed at theoriginating Oracle database.

2-1

These SQL functions include USER, USERENV, and SYSDATE; and involve theselection of data from the originating Oracle database.

• Any SQL statement that involves a table in Oracle database, and a LONG or LOBcolumn in a remote table.

An example of a remote INSERT statement that can work through the remote insertrowsource feature is as follows:

INSERT INTO gateway_table@gateway_link select * from local_table;

Using the Pass-Through FeatureThe gateway can pass SQL Server commands or statements from the application tothe SQL Server database using the DBMS_HS_PASSTHROUGH package.

Use the DBMS_HS_PASSTHROUGH package in a PL/SQL block to specify the statement tobe passed to the SQL Server database, as follows:

DECLARE num_rows INTEGER;BEGIN num_rows := DBMS_HS_PASSTHROUGH.EXECUTE_IMMEDIATE@MSQL('command');END;/

Where command cannot be one of the following:

• BEGIN TRANSACTION

• COMMIT

• ROLLBACK

• SAVE

• SHUTDOWN

• RELEASE

• SAVEPOINT

• CONNECT

• SQL Server tool commands

The DBMS_HS_PASSTHROUGH package supports passing bind values and executingSELECT statements.

Note:

TRUNCATE cannot be used in a pass-through statement.

Chapter 2Using the Pass-Through Feature

2-2

See Also:

Oracle Database PL/SQL Packages and Types Reference and Chapter 3,Features of Oracle Database Gateways, of Oracle Database HeterogeneousConnectivity User's Guide for more information about theDBMS_HS_PASSTHROUGH package.

Executing Stored Procedures and FunctionsUsing the procedural feature, the gateway can execute stored procedures that aredefined in the SQL Server database. It is not necessary to relink the gateway or definethe procedure to the gateway, but the procedure's access privileges must permitaccess by the user that the gateway is logging in as.

Standard PL/SQL statements are used to execute a stored procedure.

The gateway supports stored procedures in three mutually exclusive modes:

• Normal mode: Have access to IN/OUT arguments only

• Return value mode: Have a return value for all stored procedures

• Resultset mode: Out values are available as last result set

CHAR SemanticsThis feature allows the gateway to optionally run in CHAR Semantics mode. Rather thanalways describing SQL Server CHAR columns as CHAR(n BYTE), this feature describesthem as CHAR(n CHAR) and VARCHAR(n CHAR). The concept is similar to Oracledatabase CHAR Semantics. You need to specify HS_NLS_LENGTH_SEMANTICS=CHARgateway parameter to activate this option. Refer to Initialization Parameters for moredetail.

Multi-byte Character Sets Ratio SuppressionThis feature optionally suppresses the ratio expansion from SQL Server database toOracle database involving multi-byte character set. By default, Oracle gatewaysassume the worst ratio to prevent data being truncated or insufficient buffer sizesituation. However, if you have specific knowledge of your SQL Server database anddo not want the expansion to occur, you can specify HS_KEEP_REMOTE_COLUMN_SIZEparameter to suppress the expansion. Refer to Initialization Parameters for moredetail.

IPv6 SupportBesides full IPv6 support between Oracle databases and the gateway, IPv6 is alsosupported between this gateway and SQL Server database. Refer to theHS_FDS_CONNECT_INFO parameter in Initialization Parameters for more detail.

Chapter 2Executing Stored Procedures and Functions

2-3

Gateway Session IDLE TimeoutYou can optionally choose to terminate long idle gateway sessions automatically withthe gateway parameter HS_IDLE_TIMEOUT. Specifically, when a gateway session is idlefor more than the specified time limit, the gateway session is terminated with anypending update rolled back. Refer to the HS_IDLE_TIMEOUT parameter in InitializationParameters for more detail.

Remote User-defined Function SupportUser-defined functions in a remote non-Oracle database can be used in SQLstatements.

See Also:

Oracle Database Heterogeneous Connectivity User's Guide for moreinformation about executing user-defined functions on a non-Oracledatabase.

Return Values and Stored ProceduresBy default, all stored procedures and functions do not return a return value to the user.To enable return values, set the HS_FDS_PROC_IS_FUNC parameter value to TRUE.

See Also:

Initialization Parameters for information about both editing the initializationparameter file and the HS_FDS_PROC_IS_FUNC parameter.

Note:

If you set the HS_FDS_PROC_IS_FUNC gateway initialization parameter to TRUE,you must change the syntax of the procedure execute statement for allexisting stored procedures.

In the following example, the employee name JOHN SMYTHE is passed to the SQLServer stored procedure REVISE_SALARY. The stored procedure retrieves the salaryvalue from the SQL Server database to calculate a new yearly salary for JOHN SMYTHE.The revised salary returned in RESULT is used to update EMP in a table of an Oracledatabase:

DECLARE INPUT VARCHAR2(15); RESULT NUMBER(8,2);BEGIN

Chapter 2Gateway Session IDLE Timeout

2-4

INPUT := 'JOHN SMYTHE'; RESULT := REVISE_SALARY@MSQL(INPUT); UPDATE EMP SET SAL = RESULT WHERE ENAME =: INPUT;END;/

The procedural feature automatically converts non-Oracle data types to and fromPL/SQL data types.

Result Sets and Stored ProceduresThe Oracle Database Gateway for SQL Server provides support for stored procedureswhich return result sets.

By default, all stored procedures and functions do not return a result set to the user.To enable result sets, set the HS_FDS_RESULTSET_SUPPORT parameter value to TRUE.

See Also:

Initialization Parameters for information about both editing the initializationparameter file and the HS_FDS_RESULTSET_SUPPORT parameter. For furtherinformation about Oracle support for result sets in non-Oracle databases see Oracle Database Heterogeneous Connectivity User's Guide.

Note:

If you set the HS_FDS_RESULTSET_SUPPORT gateway initialization parameter toTRUE, then you must change the syntax of the procedure execute statementfor all existing stored procedures, else errors will occur.

When accessing stored procedures with result sets through the Oracle DatabaseGateway for SQL Server, you will be in the sequential mode of HeterogeneousServices.

The Oracle Database Gateway for SQL Server returns the following information toHeterogeneous Services during procedure description:

• All the input arguments of the remote stored procedure

• None of the output arguments

• One out argument of type ref cursor (corresponding to the first result set returnedby the stored procedure)

Client programs have to use the virtual package functionDBMS_HS_RESULT_SET.GET_NEXT_RESULT_SET to get the ref cursor for subsequent resultsets. The last result set returned is the out argument from the procedure.

The limitations of accessing result sets are the following:

• Result sets returned by a remote stored procedure have to be retrieved in theorder in which they were placed on the wire

Chapter 2Remote User-defined Function Support

2-5

• On execution of a stored procedure, all result sets returned by a previouslyexecuted stored procedure will be closed (regardless of whether the data hasbeen completely retrieved or not)

In the following example, the SQL Server stored procedure is executed to fetch thecontents of the emp and dept tables from SQL Server:

create procedure REFCURPROC (@arg1 varchar(255), @arg2 varchar(255) output)asselect @arg2 = @arg1select * from EMPselect * from DEPTgo

This stored procedure assigns the input parameter arg1 to the output parameter arg2,opens the query SELECT * FROM EMP in ref cursor rc1, and opens the query SELECT *FROM DEPT in ref cursor rc2.

OCI Program Fetching from Result Sets in Sequential ModeThe following example shows OCI program fetching from result sets in sequentialmode:

OCIEnv *ENVH;OCISvcCtx *SVCH;OCIStmt *STMH;OCIError *ERRH;OCIBind *BNDH[3];OraText arg1[20];OraText arg2[255];OCIResult *rset;OCIStmt *rstmt;ub2 rcode[3];ub2 rlens[3];sb2 inds[3];OraText *stmt = (OraText *) "begin refcurproc@MSQL(:1,:2,:3); end;";OraText *n_rs_stm = (OraText *) "begin :ret := DBMS_HS_RESULT_SET.GET_NEXT_RESULT_SET@MSQL; end;";

/* Prepare procedure call statement */

/* Handle Initialization code skipped */OCIStmtPrepare(STMH, ERRH, stmt, strlen(stmt), OCI_NTV_SYNTAX, OCI_DEFAULT);

/* Bind procedure arguments */inds[0] = 0;strcpy((char *) arg1, "Hello World");rlens[0] = strlen(arg1);OCIBindByPos(STMH, &BNDH[0], ERRH, 1, (dvoid *) arg1, 20, SQLT_CHR, (dvoid *) &(inds[0]), &(rlens[0]), &(rcode[0]), 0, (ub4 *) 0, OCI_DEFAULT);

inds[1] = -1;OCIBindByPos(STMH, &BNDH[1], ERRH, 1, (dvoid *) arg2, 20, SQLT_CHR, (dvoid *) &(inds[1]), &(rlens[1]), &(rcode[1]), 0, (ub4 *) 0, OCI_DEFAULT);

inds[2] = 0;rlens[2] = 0;OCIDescriptorAlloc(ENVH, (dvoid **) &rset, OCI_DTYPE_RSET, 0, (dvoid **) 0);


2-6

OCIBindByPos(STMH, &BNDH[2], ERRH, 2, (dvoid *) rset, 0, SQLT_RSET, (dvoid *) &(inds[2]), &(rlens[2]), &(rcode[2]), 0, (ub4 *) 0, OCI_DEFAULT);

/* Execute procedure */OCIStmtExecute(SVCH, STMH, ERRH, 1, 0, (CONST OCISnapshot *) 0, (OCISnapshot *) 0, OCI_DEFAULT);

/* Convert result set to statement handle */OCIResultSetToStmt(rset, ERRH);rstmt = (OCIStmt *) rset;

/* After this the user can fetch from rstmt *//* Issue get_next_result_set call to get handle to next_result set *//* Prepare Get next result set procedure call */

OCIStmtPrepare(STMH, ERRH, n_rs_stm, strlen(n_rs_stm), OCI_NTV_SYNTAX, OCI_DEFAULT);

/* Bind return value */OCIBindByPos(STMH, &BNDH[1], ERRH, 1, (dvoid *) rset, 0, SQLT_RSET, (dvoid *) &(inds[1]), &(rlens[1]), &(rcode[1]), 0, (ub4 *) 0, OCI_DEFAULT);

/* Execute statement to get next result set*/OCIStmtExecute(SVCH, STMH, ERRH, 1, 0, (CONST OCISnapshot *) 0, (OCISnapshot *) 0, OCI_DEFAULT);

/* Convert next result set to statement handle */OCIResultSetToStmt(rset, ERRH);rstmt = (OCIStmt *) rset;

/* Now rstmt will point to the second result set returned by theremote stored procedure */

/* Repeat execution of get_next_result_set to get the output arguments */

PL/SQL Program Fetching from Result Sets in Sequential ModeAssume that the table loc_emp is a local table exactly like the SQL Server emp table.The same assumption applies for loc_dept. The table outargs has columnscorresponding to the out arguments of the SQL Server stored procedure.

create table outargs (outarg varchar2(255), retval number);

create or replace package rcpackage is type RCTYPE is ref cursor;end rcpackage;/

declare rc1 rcpackage.rctype; rec1 loc_emp%rowtype; rc2 rcpackage.rctype; rec2 loc_dept%rowtype; rc3 rcpackage.rctype; rec3 outargs%rowtype; out_arg varchar2(255);

begin


2-7

-- Execute procedure out_arg := null; refcurproc@MSQL('Hello World', out_arg, rc1);

-- Fetch 20 rows from the remote emp table and insert them into loc_emp for i in 1 .. 20 loop fetch rc1 into rec1; insert into loc_emp (rec1.empno, rec1.ename, rec1.job, rec1.mgr, rec1.hiredate, rec1.sal, rec1.comm, rec1.deptno); end loop;

-- Close ref cursor close rc1;

-- Get the next result set returned by the stored procedure rc2 := dbms_hs_result_set.get_next_result_set@MSQL;

-- Fetch 5 rows from the remote dept table and insert them into loc_dept for i in 1 .. 5 loop fetch rc2 into rec2; insert into loc_dept values (rec2.deptno, rec2.dname, rec2.loc); end loop;

--Close ref cursor close rc2;

-- Get the output arguments from the remote stored procedure -- Since we are in sequential mode, they will be returned in the -- form of a result set rc3 := dbms_hs_result_set.get_next_result_set@MSQL;

-- Fetch them and insert them into the outargs table fetch rc3 into rec3; insert into outargs (rec3.outarg, rec3.retval);

-- Close ref cursor close rc3;

end;/

Database Compatibility Issues for SQL ServerSQL Server and Oracle databases function differently in some areas, causingcompatibility problems. The compatibility issues are described in the following links:

• Implicit Transactions (Chained Mode)

• Column Definitions

• Naming Rules

• Data Types

• Queries

• Locking

Chapter 2Database Compatibility Issues for SQL Server

2-8

Implicit Transactions (Chained Mode)The gateway supports the ANSI-standard implicit transactions. SQL Server storedprocedures must be written for this mode. Running implicit transactions allows thegateway to extend the Oracle two-phase commit protection to transactions updatingOracle and SQL Server databases.

Column DefinitionsBy default, a SQL Server table column cannot contain null values unless NULL isspecified in the column definition. SQL Server assumes all columns cannot containnull values unless you set a SQL Server option to override this default.

For an Oracle table, null values are allowed in a column unless NOT NULL is specifiedin the column definition.

Naming RulesNaming rule issues include the following:

• Rules for Naming Objects

• Case Sensitivity

Rules for Naming ObjectsOracle and SQL Server use different database object naming rules. For example, themaximum number of characters allowed for each object name can be different. Also,the use of single and double quotation marks, case sensitivity, and the use ofalphanumeric characters can all be different.

See Also:

Oracle Database Reference and SQL Server documentation.

Case SensitivityThe Oracle database defaults to uppercase unless you surround identifiers with doublequote characters. For example, to refer to the SQL Server table called emp, enter thename with double quote characters, as follows:

SQL> SELECT * FROM "emp"@MSQL;

However, to refer to the SQL Server table called emp owned by Scott from an Oracleapplication, enter the following:

SQL> SELECT * FROM "Scott"."emp"@MSQL;

If the SQL Server table called emp is owned by SCOTT, a table owner name inuppercase letters, you can enter the owner name without double quote characters, asfollows:


2-9

SQL> SELECT * FROM SCOTT."emp"@MSQL;

or

SQL> SELECT * FROM scott."emp"@MSQL;

Oracle recommends that you surround all SQL Server object names with double quotecharacters and use the exact letter case for the object names as they appear in theSQL Server data dictionary. This convention is not required when referring to thesupported Oracle data dictionary tables or views listed in Data Dictionary.

If existing applications cannot be changed according to these conventions, createviews in Oracle to associate SQL Server names to the correct letter case. Forexample, to refer to the SQL Server table emp from an existing Oracle application byusing only uppercase names, define the following view:

SQL> CREATE VIEW EMP (EMPNO, ENAME, SAL, HIREDATE) AS SELECT "empno", "ename", "sal", "hiredate" FROM "emp"@MSQL;

With this view, the application can issue statements such as the following:

SQL> SELECT EMPNO, ENAME FROM EMP;

Using views is a workaround solution that duplicates data dictionary informationoriginating in the SQL Server data dictionary. You must be prepared to update theOracle view definitions whenever the data definitions for the corresponding tables arechanged in the SQL Server database.

Data TypesData type issues include the following:

• Binary Literal Notation

• Bind Variables With LONG Columns

• Data Type Conversion

Binary Literal NotationOracle SQL uses hexadecimal digits surrounded by single quotes to express literalvalues being compared or inserted into columns defined as data type RAW.

This notation is not converted to syntax compatible with the SQL Server VARBINARYand BINARY data types (a 0x followed by hexadecimal digits, surrounded by singlequotes).

For example, the following statement is not supported:

SQL> INSERT INTO BINARY_TAB@MSQL VALUES ('0xff')

Where BINARY_TAB contains a column of data type VARBINARY or BINARY. Use bindvariables when inserting into or updating VARBINARY and BINARY data types.

Bind Variables With LONG ColumnsThe gateway does not support using bind variables to update columns of data typeLONG.


2-10

Data Type ConversionSQL Server does not support implicit date conversions. Such conversions must beexplicit.

For example, the gateway issues an error for the following SELECT statement:

SELECT DATE_COL FROM TEST@MSQL WHERE DATE_COL = "1-JAN-2004";

To avoid problems with implicit conversions, add explicit conversions, as in thefollowing:

SELECT DATE_COL FROM TEST@MSQL WHERE DATE_COL = TO_DATE("1-JAN-2004")

See Also:

Data Type Conversion for more information about restrictions on data types.

QueriesQuery issues include the following:

• Row Selection

• Empty Strings

• Empty Bind Variables

Row SelectionSQL Server evaluates a query condition for all selected rows before returning any ofthe rows. If there is an error in the evaluation process for one or more rows, no rowsare returned even though the remaining rows satisfy the condition.

Oracle evaluates the query condition row-by-row and returns a row when theevaluation is successful. Rows are returned until a row fails the evaluation.

Empty StringsOracle processes an empty string in a SQL statement as a null value. SQL Serverprocesses an empty string as an empty string.

When comparing an empty string the gateway passes literal empty strings to the SQLServer database without any conversion. If you intended an empty string to representa null value, SQL Server does not process the statement that way; it uses the emptystring.

You can avoid this problem by using NULL or IS NULL in the SQL statement instead ofthe empty string syntax, as in the following example:

SELECT * from "emp"@MSQL where "ename" IS NULL;

To select an empty string:


2-11

• For VARCHAR columns, the gateway returns an empty string to the Oracle databaseas NULL value.

• For CHAR columns, the gateway returns the full size of the column with eachcharacter as empty space (' ').

Empty Bind VariablesFor VARCHAR bind variables, the gateway passes empty bind variables to the SQLServer database as a NULL value.

LockingThe locking model for an SQL Server database differs significantly from the Oraclemodel. The gateway depends on the underlying SQL Server behavior, so the followingpossible scenarios can affect Oracle applications that access SQL Server through thegateway:

• Read access might block write access

• Write access might block read access

• Statement-level read consistency is not guaranteed

See Also:

SQL Server documentation for information about the SQL Server lockingmodel.

Known RestrictionsIf you encounter incompatibility problems not listed in this section or in "KnownProblems", contact Oracle Support Services. The following section describes theknown restrictions and includes suggestions for dealing with them when possible:

• Multiple Open Statements

• Transactional Integrity

• Transaction Capability

• COMMIT or ROLLBACK in PL/SQL Cursor Loops Closes Open Cursors

• Stored Procedures

• Pass-Through Feature

• DDL Statements

• SQL Syntax

• Functions

• SQL*Plus COPY Command with Lowercase Table Names

• Database Links

Chapter 2Known Restrictions

2-12

Note:

If you have any questions or concerns about the restrictions, contact OracleSupport Services.

Multiple Open StatementsAccessing SQL Server has the limitation that one open statement or cursor is allowedfor each connection. If a second statement or cursor needs to open in the sametransaction to access SQL Server, it requires a new connection.

Because of this limitation multiple open statements or cursors within the sametransaction can lock each other because they use different connections to SQL Server.

To avoid this restriction, issue a commit, or modify the logic, or both.

Transactional IntegrityThe gateway cannot guarantee transactional integrity in the following cases:

• When a statement that is processed by the gateway causes an implicit commit inthe target database

• When the target database is configured to work in Autocommit Mode

Note:

Oracle strongly recommends the following:

– If you know that executing a particular statement causes an implicitcommit in the target database, then ensure that this statement isexecuted in its own transaction.

The gateway sets Autocommit Mode to Off when a connection is established to theSQL Server database.

Transaction CapabilityThe gateway does not support savepoints. If a distributed update transaction is underway involving the gateway, and a user attempts to create a savepoint, the followingerror occurs:

ORA-02070: database dblink does not support savepoint in this context

By default, the gateway is configured as COMMIT_CONFIRM.

COMMIT or ROLLBACK in PL/SQL Cursor Loops Closes OpenCursors

Any COMMIT or ROLLBACK issued in a PL/SQL cursor loop closes all open cursors, whichcan result in the following error:


2-13

ORA-1002: fetch out of sequence

To prevent this error, move the COMMIT or ROLLBACK statement outside the cursor loop.

Stored ProceduresThe Oracle transaction manager or Oracle COMMIT or ROLLBACK commands cannotcontril changes issued through stored procedures that embed commits or rollbacks

When accessing stored procedures with result sets through the Oracle DatabaseGateway for SQL Server, you must work in the sequential mode of HeterogeneousServices.

When accessing stored procedures with multiple result sets through the OracleDatabase Gateway for SQL Server, you must read all the result sets before continuing.

Output parameters of stored procedures must be initialized to an empty string.

Pass-Through FeatureIf the SQL statements being passed through the gateway result in an implicit commit atthe SQL Server database, the Oracle transaction manager is unaware of the commitand an Oracle ROLLBACK command cannot be used to roll back the transaction.

DDL StatementsSQL Server requires some DDL statements to be executed in their own transaction,and only one DDL statement can be executed in a given transaction.

If you use these DDL statements in a SQL Server stored procedure and you executethe stored procedure through the gateway using the procedural feature, or, if youexecute the DDL statements through the gateway using the pass-through feature, anerror condition might result. This is because the procedural feature and the pass-through feature of the gateway cannot guarantee that the DDL statements areexecuted in their own separate transaction.

The following SQL Server DDL statements can cause an error condition if you attemptto pass them with the gateway pass-through feature, or if you execute a SQL Serverstored procedure that contains them:

• ALTER DATABASE

• CREATE DATABASE

• CREATE INDEX

• CREATE PROCEDURE

• CREATE TABLE

• CREATE VIEW

• DISK INIT

• DROP <object>

• DUMP TRANSACTION

• GRANT


2-14

• LOAD DATABASE

• LOAD TRANSACTION

• RECONFIGURE

• REVOKE

• SELECT INTO

• TRUNCATE TABLE

• UPDATE STATISTICS

See Also:

SQL Server documentation for more information about DDL statements.

SQL SyntaxThis section lists restrictions on the following SQL syntax:

• WHERE CURRENT OF Clause

• CONNECT BY Clause

• Functions in Subqueries

• Parameters in Subqueries

• Data Dictionary Table and Views in UPDATE Statement

• ROWID

• TO_DATE

• EXPLAIN PLAN Statement

See Also:

Supported SQL Syntax and Functions for more information about restrictionson SQL syntax.

WHERE CURRENT OF ClauseUPDATE and DELETE statements with the WHERE CURRENT OF clause are not supportedby the gateway because they rely on the Oracle ROWID implementation. To update ordelete a specific row through the gateway, a condition style WHERE clause must beused.

CONNECT BY ClauseThe gateway does not support the CONNECT BY clause in a SELECT statement.


2-15

Functions in SubqueriesBind variables and expressions are not supported as operands in string functions ormathematical functions, when part of subquery in an INSERT, UPDATE, or DELETE SQLstatement.

Parameters in SubqueriesDue to a limitation in SQL Server, you cannot use parameters in subqueries.

Data Dictionary Table and Views in UPDATE StatementData dictionary tables and views in the SET clause of an UPDATE statement are notsupported.

ROWIDThe Oracle ROWID implementation is not supported.

TO_DATETO_DATE is a reserved word and cannot be used as a database identifier name.

EXPLAIN PLAN StatementThe EXPLAIN PLAN statement is not supported.

FunctionsThe following restrictions apply to using functions:

• Unsupported functions cannot be used in statements that refer to LONG columns.

• When negative numbers are used as the second parameter in a SUBSTR function,incorrect results are returned. This is due to incompatibility between the OracleSUBSTR function and the equivalent in SQL Server.

SQL*Plus COPY Command with Lowercase Table NamesYou need to wrap lower case table names in double quotes.

For example:

copy from tkhouser/tkhouser@inst1 insert loc_tkhodept using select * from "tkhodept"@holink2;

Database LinksThe gateway is not multithreaded and cannot support shared database links. Eachgateway session spawns a separate gateway process and connections cannot beshared.


2-16

Known ProblemsThis section describes known problems and includes suggestions for correcting themwhen possible. If you have any questions or concerns about the problems, contactOracle Support Services. A current list of problems is available online. Contact yourlocal Oracle office for information about accessing the list.

The following known problems are described in this section:

• Encrypted Format Login

• Date Arithmetic

• SQL Server IMAGE_ TEXT and NTEXT Data Types

• String Functions

• Schema Names and PL/SQL

• Data Dictionary Views and PL/SQL

• Stored Procedures

Encrypted Format LoginThe Oracle9i database (Release 9.2 and earlier) supported an Oracle initializationparameter, DBLINK_ENCRYPT_LOGIN. When this parameter is set to TRUE, the passwordfor the login user ID is not sent over the network.

If this parameter is set to TRUE in the initialization parameter file used by the Oracle9idatabase, you must change the setting to FALSE, the default setting, to allow Oracle9ito communicate with the gateway.

In the current release, the DBLINK_ENCRYPT_LOGIN initialization parameter is obsolete,so you do not need to check it.

Date ArithmeticThe following SQL expressions do not function correctly with the gateway:

date + numbernumber + datedate - numberdate1 - date2

Statements with the preceding expressions are sent to the SQL Server databasewithout any translation. Since SQL Server does not support these date arithmeticfunctions, the statements return an error.

SQL Server IMAGE, TEXT and NTEXT Data TypesThe following restrictions apply when using IMAGE, TEXT, and NTEXT data types:

• An unsupported SQL function cannot be used in a SQL statement that accesses acolumn defined as SQL Server data type IMAGE, TEXT, or NTEXT.

• You cannot use SQL*Plus to select data from a column defined as SQL Serverdata type IMAGE, TEXT, or NTEXT when the data is greater than 80 characters in

Chapter 2Known Problems

2-17

length. Oracle recommends using Pro*C or Oracle Call Interface to access suchdata in a SQL Server database.

• IMAGE, TEXT, and NTEXT data cannot be read through pass-through queries.

• If a SQL statement is accessing a table including an IMAGE, TEXT, or NTEXT column,the statement will be sent to SQL Server as two separate statements. Onestatement to access the IMAGE, TEXT or NTEXT column, and a second statement forthe other columns in the original statement.

The gateway does not support the PL/SQL function COLUMN_VALUE_LONG of theDBMS_SQL package.

See Also:

Supported SQL Syntax and Functions for more information about restrictionson SQL syntax.

String FunctionsIf you concatenate numeric literals using the "||" or CONCAT operator when using thegateway to query a SQL Server database, the result is an arithmetic addition. Forexample, the result of the following statement is 18:

SQL> SELECT 9 || 9 FROM DUAL@MSQL;

The result is 99 when using Oracle to query an Oracle database.

Schema Names and PL/SQLIf you do not prefix a SQL Server database object with its schema name in a SQLstatement within a PL/SQL block, the following error message occurs:

ORA-6550 PLS-201 Identifier table_name must be declared.

Change the SQL statement to include the schema name of the object.

Data Dictionary Views and PL/SQLYou cannot refer to data dictionary views in SQL statements that are inside a PL/SQLblock.

Stored ProceduresReturn values of stored procedures that return result sets are incorrect.

Chapter 2Known Problems

2-18

3Case Studies

The following case studies for SQL Server demonstrate some of the features of theOracle Database Gateway. You can verify that the gateway is installed and operatingcorrectly by using the demonstration files included in the distribution media.

The demonstration files are automatically copied to disk when the gateway is installed.

Topics:

• Case Descriptions

• Installation Media Contents

• Demonstration Files

• Demonstration Requirements

• Creating Demonstration Tables

• Case 1: Simple Queries

• Case 2: A More Complex Query

• Case 3: Joining SQL Server Tables

• Case 4: Write Capabilities

• Case 5: Data Dictionary Query

• Case 6: The Pass-Through Feature

• Case 7: Executing Stored Procedures

Case DescriptionsThe cases illustrate:

• A simple query (Case 1)

• A more complex query (Case 2)

• Joining SQL Server tables (Case 3)

• Write capabilities (Case 4)

• A data dictionary query (Case 5)

• The pass-through feature (Case 6)

• Executing stored procedures (Case 7)

Installation Media ContentsThe installation media contains the following:

• Demonstration files

3-1

• One SQL script file that creates the demonstration tables and stored procedures inthe SQL Server database

• One SQL script file that drops the demonstration tables and stored proceduresfrom the SQL Server database

Demonstration FilesAfter a successful gateway installation, use the demonstration files stored in thedirectory ORACLE_HOME\dg4msql\demo where ORACLE_HOME is the directory under whichthe gateway is installed. The directory contains the following demonstration files:

• bldmsql.sql

• case1.sql

• case2.sql

• case3.sql

• case4a.sql

• case4b.sql

• case4c.sql

• case5.sql

• case6a.sql

• case6b.sql

• case7.sql

• dropmsql.sql

Demonstration RequirementsThe case studies assume these requirements have been met:

• The gateway demonstration tables and stored procedures are installed in the SQLServer database

• The Oracle database has an account named SCOTT with a password of TIGER

• The Oracle database has a database link called GTWLINK (set up as public orprivate to the user SCOTT) which connects the gateway to a SQL Server databaseas SCOTT with password TIGER2

For example, you can create the database link as follows:

SQL> CREATE DATABASE LINK GTWLINK CONNECT TO SCOTT 2 IDENTIFIED BY TIGER2 USING 'GTWSID';

• Oracle Net Services is configured correctly and running

Creating Demonstration TablesThe case studies are based on the GTW_EMP, GTW_DEPT, and GTW_SALGRADE tables andthe stored procedures InsertDept and GetDept. If the demonstration tables and storedprocedures have not been created in the SQL Server database, use the bldmsql.sqlscript to create them. Enter the following:

Chapter 3Demonstration Files

3-2

> isql -USCOTT -PTIGER2 -ibldmsql.sql

The script creates the demonstration tables and stored procedures in the SQL Serverdatabase accordingly:

CREATE TABLE GTW_EMP (EMPNO SMALLINT NOT NULL ENAME VARCHAR(10),JOB VARCHAR(9),MGR SMALLINT,HIREDATE DATETIME,SAL NUMERIC(7,2),COMM NUMERIC(7,2),DEPTNO SMALLINT)go

CREATE TABLE GTW_DEPT (DEPTNO SMALLINT NOT NULL,DNAME VARCHAR(14),LOC VARCHAR(13)) go

CREATE TABLE GTW_SALGRADE (GRADE MONEY,LOSAL NUMERIC(9,4),HISAL NUMERIC(9,4))go

DROP PROCEDURE InsertDeptgo

CREATE PROCEDURE InsertDept (@dno INTEGER, @dname VARCHAR(14), @loc VARCHAR(13))AS INSERT INTO GTW_DEPT VALUES (@dno, @dname, @loc)go

DROP PROCEDURE GetDeptgo

CREATE PROCEDURE GetDept (@dno INTEGER, @dname VARCHAR(14) OUTPUT)AS SELECT @dname=DNAME FROM GTW_DEPT WHERE DEPTNO=@dnogo

Demonstration Table DefinitionsThe following table definitions use information retrieved by the SQL*PLUS DESCRIBEcommand:

GTW_EMP

Name Null? Type------------------------------- -------- ----EMPNO NOT NULL NUMBER(5)ENAME VARCHAR2(10)JOB VARCHAR2(9)MGR NUMBER(5)HIREDATE DATESAL NUMBER(7,2)COMM NUMBER(7,2)DEPTNO NUMBER(5)

Chapter 3Creating Demonstration Tables

3-3

GTW_DEPT

Name Null? Type------------------------------- -------- ----DEPTNO NOT NULL NUMBER(5)DNAME VARCHAR2(14)LOC VARCHAR2(13)

GTW_SALGRADE

Name Null? Type------------------------------- -------- ----GRADE NUMBER(19,4)LOSAL NUMBER(9,4)HISAL NUMBER(9,4)

Demonstration Table ContentsThe contents of the SQL Server tables are:

GTW_EMP

EMPNO ENAME JOB MGR HIREDATE SAL COMM DEPTNO----- ----- --- --- -------- --- ---- ------7369 SMITH CLERK 7902 17-DEC-80 800 207499 ALLEN SALESMAN 7698 20-FEB-81 1600 300 307521 WARD SALESMAN 7698 22-FEB-81 1250 500 307566 JONES MANAGER 7839 02-APR-81 2975 207654 MARTIN SALESMAN 7698 28-SEP-81 1250 1400 307698 BLAKE MANAGER 7839 01-MAY-81 2850 307782 CLARK MANAGER 7839 09-JUN-81 2450 107788 SCOTT ANALYST 7566 09-DEC-82 3000 207839 KING PRESIDENT 17-NOV-81 5000 107844 TURNER SALESMAN 7698 08-SEP-81 1500 0 307876 ADAMS CLERK 7788 12-JAN-83 1100 207900 JAMES CLERK 7698 03-DEC-81 950 307902 FORD ANALYST 7566 03-DEC-81 3000 207934 MILLER CLERK 7782 23-JAN-82 1300 10

GTW_DEPT

DEPTNO DNAME LOC ----- -------------- -------- 10 ACCOUNTING NEW YORK 20 RESEARCH DALLAS 30 SALES CHICAGO 40 OPERATIONS BOSTON

GTW_SALGRADE

GRADE LOSAL HISAL------ ------ ----- 1 700 1200 2 1201 1400 3 1401 2000 4 2001 3000 5 3001 9999

Chapter 3Creating Demonstration Tables

3-4

Case 1: Simple QueriesCase 1 demonstrates the following:

• A simple query

• A simple query retrieving full date information

The first query retrieves all the data from GTW_DEPT and confirms that the gateway isworking correctly. The second query retrieves all the data from GTW_EMP including thetime portion of the hire date because the default date format was set to DD-MON-YYHH24:MM:SS for the session by an ALTER SESSION command.

Case 2: A More Complex QueryCase 2 demonstrates the following:

• The functions SUM(expression) and NVL(expr1, expr2) in the SELECT list

• The GROUP BY and HAVING clauses

This query retrieves the departments from GTW_EMP whose total monthly expenses arehigher than $10,000.

Case 3: Joining SQL Server TablesCase 3 demonstrates the following:

• Joins between SQL Server tables

• Subselects

The query retrieves information from three SQL Server tables and relates theemployees to their department name and salary grade, but only for those employeesearning more than the average salary.

Case 4: Write CapabilitiesCase 4 is split into three cases and demonstrates the following:

• DELETE Statement

• UPDATE Statement

• INSERT Statement

DELETE StatementCase 4a demonstrates bind values and subselect. All employees in department 20 andone employee, WARD, in department 30 are deleted.

UPDATE StatementCase 4b provides an example of a simple UPDATE statement. In this example,employees are given a $100 a month salary increase.

Chapter 3Case 1: Simple Queries

3-5

INSERT StatementCase 4c is an example of a simple insert statement that does not provide informationfor all columns.

Case 5: Data Dictionary QueryCase 5 demonstrates data dictionary mapping. It retrieves all the tables and views thatexist in the SQL Server database that begin with GTW.

Case 6: The Pass-Through FeatureCase 6 demonstrates the gateway pass-through feature which allows an application tosend commands or statements to SQL Server.

This case demonstrates:

• A pass-through UPDATE statement using bind variables

• A pass-through SELECT statement

UPDATE StatementCase 6a provides an example of a pass-through UPDATE statement with bind variables.In this example, the salary for EMPNO 7934 is set to 4000.

SELECT StatementCase 6b provides an example of a pass-through SELECT statement. The data that isreturned from the SELECT statement is inserted into a local table at the Oracledatabase.

Case 7: Executing Stored ProceduresCase 7 demonstrates the gateway executing a stored procedure in the SQL Serverdatabase.

Chapter 3Case 5: Data Dictionary Query

3-6

AData Type Conversion

The gateway converts SQL Server data types to Oracle data types as follows:

Table A-1 Data Type Mapping and Restrictions

SQL Server Oracle Comment If Oracle uses large varchar(32k)

BIGINT NUMBER(20)

BIGINT IDENTITY NUMBER(20)

BINARY RAW -

BIT NUMBER(3) -

CHAR CHAR -

DATETIME DATE Fractional parts of a second aretruncated

DECIMAL NUMBER(p[,s]) -

DECIMAL IDENTITY NUMBER(p[,s])

FLOAT FLOAT(53) -

IMAGE LONG RAW -

INT NUMBER(10)

INT IDENTITY NUMBER(10)

MONEY NUMBER(19,4) -

NCHAR NCHAR if the size is 1000 or less. If thesize is more than 1000, then it willbe mapped to LONG OracleDatabase Character Set =Unicode, otherwise, it is notsupported.

NTEXT LONG if Oracle DB Character Set =Unicode. Otherwise, it is notsupported

NVARCHAR NVARCHAR -

NVARCHAR(MAX) LONG 4000 < N

if Oracle DB Character Set =Unicode. Otherwise, it is notsupported.

32767 < N

NUMERIC NUMBER(p[,s]) -

NUMERIC IDENTITY NUMBER(p[,s])

REAL FLOAT(24) -

SMALLDATETIME DATE -

A-1

Table A-1 (Cont.) Data Type Mapping and Restrictions

SQL Server Oracle Comment If Oracle uses large varchar(32k)

SMALLMONEY NUMBER(10,4) -

SMALLINT NUMBER(5) -

SMALLINT IDENTITY NUMBER(5)

SYSNAME NVARCHAR -

TEXT LONG

TIMESTAMP RAW -

TINYINT NUMBER(3) -

TINYINT IDENTITY NUMBER(3)

VARBINARY RAW 1 N 2000 1 <= N <= 32767

VARBINARY(MAX) LONG RAW 2000 < N N < 32767

VARCHAR VARCHAR2 N 4000 N <= 32767

VARCHAR(MAX) LONG 4000 < N 32767 < N

XML LONG if Oracle Database Character Set= Unicode. Otherwise, it is notsupported.

Appendix A

A-2

BSupported SQL Syntax and Functions

The following topics describe supported SQL Syntax and Functions:

• Supported SQL Statements

• Oracle Functions

Supported SQL StatementsWith a few exceptions, the gateway provides full support for Oracle DELETE, INSERT,SELECT, and UPDATE statements.

The gateway does not support Oracle data definition language (DDL) statements. Noform of the Oracle ALTER, CREATE, DROP, GRANT, or TRUNCATE statements can be used.Instead, use the pass-through feature of the gateway if you need to use DDLstatements against the SQL Server database.

Note:

TRUNCATE cannot be used in a pass-through statement.

See Also:

Oracle Database Reference for detailed descriptions of keywords,parameters, and options.

DELETEThe DELETE statement is fully supported. However, only Oracle functions supported bySQL Server can be used.

See Also:

"Functions Supported by SQL Server" for a list of supported functions.

INSERTThe INSERT statement is fully supported. However, only Oracle functions supported bySQL Server can be used.

B-1

See Also:


SELECTThe SELECT statement is fully supported, with these exceptions:

• CONNECT BY condition

• NOWAIT

• START WITH condition

• WHERE CURRENT OF

UPDATEThe UPDATE statement is fully supported. However, only Oracle functions supported bySQL Server can be used.

See Also:


Oracle FunctionsAll functions are evaluated by the SQL Server database after the gateway hasconverted them to SQL Server SQL equivalents. The exception is the TO_DATEfunction, which is evaluated by the gateway.

Functions Not Supported by SQL ServerOracle SQL functions with no equivalent function in SQL Server are not supported in DELETE, INSERT, or UPDATE statements, but are evaluated by the Oracle database if thestatement is a SELECT statement. That is, the Oracle database performs post-processing of SELECT statements sent to the gateway.

If an unsupported function is used in a DELETE, INSERT, or UPDATE, statement, thefollowing Oracle error occurs:

ORA-02070: database db_link_name does not support function in this context

Functions Supported by SQL ServerThe gateway translates the following Oracle database functions in SQL statements totheir equivalent SQL Server functions:

• Arithmetic Operators

Appendix BOracle Functions

B-2

• Comparison Operators

• Pattern Matching

• Group Functions

• String Functions

• Other Functions

Arithmetic Operators

Oracle SQL Server

+ +

- -

* *

/ /

Comparison Operators

Oracle SQL Server

= =

> >

< <

>= >=

<= <=

<>, !=, ^= <>

IS NOT NULL IS NOT NULL

IS NULL IS NULL

Pattern Matching

Oracle SQL Server

LIKE LIKE

NOT LIKE NOT LIKE

Group Functions

Oracle SQL Server

AVG AVG

COUNT COUNT

MAX MAX

MIN MIN


B-3

Oracle SQL Server

SUM SUM

String Functions

Oracle SQL Server

||, CONCAT + (expression1 + expression2)

ASCII ASCII

CHR CHAR

INSTR (with two arguments) CHARINDEX

LENGTH () LEN ()

LENGTHB () DATALENGTH ()

LENGTHC () LEN ()

LOWER LOWER

LTRIM LTRIM

RTRIM RTRIM

SUBSTR (second argument cannot be anegative number)

SUBSTRING

UPPER UPPER

Other Functions

Oracle SQL Server

ABS ABS

CEIL CEILING

COS COS

EXP EXP

FLOOR FLOOR

LN LOG

LOG LOG10

MOD %

NOT NVL IS NOT NULL

NVL IS NULL

POWER POWER

ROUND ROUND

SIN SIN

SQRT SQRT

TAN TAN


B-4

Functions Supported by the GatewayIf an Oracle function has no equivalent function in SQL Server, the Oracle function isnot translated into the SQL statement and must be post-processed if the SQLstatement is a SELECT.

The gateway, however, does support the TO_DATE function equivalent in SQL Server,as follows:

TO_DATE(date_string | date_column)

where:

• date_string is converted to a string with the following format:

yyyy-mm-dd hh:mi:ss.fff

Note:

Supply the date string with the same format as the result (that is, yyyyy-mm-dd hh:mi:ss.fff).

• date_column is a column with a date data type. It is converted to a parameter witha timestamp data type.


B-5

CData Dictionary

The Oracle Database Gateway for SQL Server translates a query that refers to anOracle database data dictionary table into a query that retrieves the data from SQLServer system tables. You perform queries on data dictionary tables over the databaselink in the same way you query data dictionary tables in the Oracle database. Thegateway data dictionary is similar to the Oracle database data dictionary inappearance and use.

Topics:

• Data Dictionary Support

• Data Dictionary Mapping

• Gateway Data Dictionary Descriptions

Data Dictionary SupportThe following paragraphs describe the Oracle Database Gateway for SQL Server datadictionary support.

SQL Server System TablesSQL Server data dictionary information is stored in the SQL Server database as SQLServer system tables. All SQL Server system tables have names prefixed with "sys".The SQL Server system tables define the structure of a database. When you changedata definitions, SQL Server reads and modifies the SQL Server system tables to addinformation about the user tables.

Accessing the Gateway Data DictionaryAccessing a gateway data dictionary table or view is identical to accessing a datadictionary in an Oracle database. You issue a SQL SELECT statement specifying adatabase link. The Oracle database data dictionary view and column names are usedto access the gateway data dictionary in an Oracle database. Synonyms of supportedviews are also acceptable. For example, the following statement queries the datadictionary table ALL_CATALOG to retrieve all table names in the SQL Server database:

SQL> SELECT * FROM "ALL_CATALOG"@MSQL;

When a data dictionary access query is issued, the gateway:

1. Maps the requested table, view, or synonym to one or more SQL Server systemtable names. The gateway translates all data dictionary column names to theircorresponding SQL Server column names within the query. If the mappinginvolves one SQL Server system table, the gateway translates the requested tablename to its corresponding SQL Server system table name within the query. If themapping involves multiple SQL Server system tables, the gateway constructs ajoin in the query using the translated SQL Server system table names.

C-1

2. Sends the translated query to SQL Server.

3. Might convert the retrieved SQL Server data to give it the appearance of theOracle database data dictionary table.

4. Passes the data dictionary information from the translated SQL Server systemtable to the Oracle database.

Note:

The values returned when querying the gateway data dictionary mightnot be the same as the ones returned by the Oracle SQL*Plus DESCRIBEcommand.

Direct Queries to SQL Server TablesQueries issued directly to individual SQL Server system tables are allowed but theyreturn different results because the SQL Server system table column names differfrom those of the data dictionary view. Also, certain columns in an SQL Server systemtable cannot be used in data dictionary processing.

Supported Views and TablesThe gateway supports the following views and tables:

ALL_CATALOG ALL_COL_COMMENTS

ALL_CONS_COLUMNS ALL_CONSTRAINTS

ALL_IND_COLUMNS ALL_INDEXES

ALL_OBJECTS ALL_TAB_COLUMNS

ALL_TAB_COMMENTS ALL_TABLES

ALL_USERS ALL_VIEWS

DBA_CATALOG DBA_COL_COMMENTS

DBA_OBJECTS DBA_TAB_COLUMNS

DBA_TAB_COMMENTS DBA_TABLES

DICT_COLUMNS DICTIONARY

DUAL TABLE_PRIVILEGES

Appendix CData Dictionary Support

C-2

USER_CATALOG USER_COL_COMMENTS

USER_CONS_COLUMNS USER_CONSTRAINTS

USER_IND_COLUMNS USER_INDEXES

USER_OBJECTS USER_TAB_COLUMNS

USER_TAB_COMMENTS USER_TABLES

USER_USERS USER_VIEWS

No other Oracle database data dictionary tables or views are supported. If you use aview not on the list, you will receive the Oracle database error code for no more rowsavailable.

Queries through the gateway of any data dictionary table or view beginning with ALL_can return rows from the SQL Server database even when access privileges for thoseSQL Server objects have not been granted. When querying an Oracle database withthe Oracle data dictionary, rows are returned only for those objects you are permittedto access.

Data Dictionary MappingThe tables in this section list Oracle data dictionary view names and the equivalentSQL Server system tables used. A plus sign (+) indicates that a join operation isinvolved.

Table C-1 Oracle Data Dictionary View Names and SQL Server Equivalents

View Name SQL Server System Table Name

ALL_CATALOG sysusers + sysobjects

ALL_COL_COMMENTS sysusers + sysobjects + syscolumns

ALL_CONS_COLUMNS sp_pkeys + sp_fkeys

ALL_CONSTRAINTS sysusers + sysobjects + sysindexes +sysconstraints + sysreferences

ALL_IND_COLUMNS sysusers + sysindexes + syscolumns

ALL_INDEXES sysusers + sysindexes + sysobjects

ALL_OBJECTS sysusers + sysobjects + sysindexes

ALL_TAB_COLUMNS sysusers + sysobjects + syscolumns

ALL_TAB_COMMENTS sysusers + sysobjects

ALL_TABLES sysusers + sysobjects

ALL_USERS sysusers

ALL_VIEWS sysusers + sysobjects + syscomments

DBA_CATALOG sysusers + sysobjects

Appendix CData Dictionary Mapping

C-3

Table C-1 (Cont.) Oracle Data Dictionary View Names and SQL ServerEquivalents

View Name SQL Server System Table Name

DBA_COL_COMMENTS sysusers + sysobjects + syscolumns

DBA_OBJECTS sysusers + sysobjects + sysindexes

DBA_TABLES sysusers + sysobjects

DBA_TAB_COLUMNS sysusers + sysobjects + syscolumns

DBA_TAB_COMMENTS sysusers + sysobjects

DICT_COLUMNS sysobjects + syscolumns

DICTIONARY sysobjects

DUAL sysusers

TABLE_PRIVILEGES sysprotects + sysusers + sysobjects

USER_CATALOG sysusers + sysobjects

USER_COL_COMMENTS sysusers + sysobjects + syscolumns

USER_CONS_COLUMNS sp_pkeys + sp_fkeys

USER_CONSTRAINTS sysusers + sysobjects + sysindexes +sysconstraints + sysreferences

USER_IND_COLUMNS sysusers + sysindexes + syscolumns

USER_INDEXES sysusers + sysindexes + sysobjects

USER_OBJECTS sysusers + sysobjects + sysindexes

USER_TAB_COLUMNS sysusers + sysobjects + syscolumns

USER_TAB_COMMENTS sysusers + sysobjects

USER_TABLES sysusers + sysobjects

USER_USERS sysusers

USER_VIEWS sysusers + sysobjects + syscomments

Default Column ValuesThere is a minor difference between the gateway data dictionary and a typical Oracledatabase data dictionary. The Oracle database columns that are missing in an SQLServer system table are filled with zeros, spaces, null values, not-applicable values(N.A.), or default values, depending on the column type.

Gateway Data Dictionary DescriptionsThe gateway data dictionary tables and views provide the following information:

• Name, data type, and width of each column

• The contents of columns with fixed values

They are described here with information retrieved by an Oracle SQL*Plus DESCRIBEcommand. The values in the Null? column might differ from the Oracle database data

Appendix CGateway Data Dictionary Descriptions

C-4

dictionary tables and views. Any default value is shown to the right of an item, but thisis not information returned by DESCRIBE.

Note:

The column width of some columns in the translated data dictionary tableswould be different when the gateway connects to a SQL Server Version 7.0database.

ALL_CATALOGTable C-2 ALL_CATALOG

Name Type Value

OWNER VARCHAR2(256) -

TABLE_NAME VARCHAR2(256) -

TABLE_TYPE VARCHAR2(5) "TABLE" or "VIEW"

ALL_COL_COMMENTSTable C-3 ALL_COL_COMMENTS

Name Type Value



COLUMN_NAME VARCHAR2(256) -

COMMENTS VARCHAR2(1) -

ALL_CONS_COLUMNSTable C-4 ALL_CONS_COLUMNS

Name Type Value


CONSTRAINT_NAME VARCHAR2(256) -



POSITION NUMBER(5) -

Appendix CALL_CATALOG

C-5

ALL_CONSTRAINTSTable C-5 ALL_CONSTRAINTS

Name Type Value



CONSTRAINT_TYPE VARCHAR2(1) "C" or "P" or "R" or"U"


SEARCH_CONDITION VARCHAR2(1) NULL

R_OWNER VARCHAR2(256) -

R_CONSTRAINT_NAME VARCHAR2(256) -

DELETE_RULE VARCHAR2(1) NULL

STATUS VARCHAR2(1) NULL

DEFERRABLE VARCHAR2(1) NULL

DEFERRED VARCHAR2(1) NULL

VALIDATED VARCHAR2(1) NULL

GENERATED VARCHAR2(1) NULL

BAD VARCHAR2(1) NULL

RELY VARCHAR2(1) NULL

LAST_CHANGE DATE -

ALL_IND_COLUMNSTable C-6 ALL_IND_COLUMNS

Name Type Value

INDEX_OWNER VARCHAR2(256) -

INDEX_NAME VARCHAR2(256) -

TABLE_OWNER VARCHAR2(256) -



COLUMN_POSITION NUMBER(3) -

COLUMN_LENGTH NUMBER -

Char_LENGTH NUMBER -

DESCEND VARCHAR2(4) -

Appendix CALL_CONSTRAINTS

C-6

ALL_INDEXESTable C-7 ALL_INDEXES

Name Type Value



INDEX_TYPE VARCHAR2(1) NULL



TABLE_TYPE VARCHAR(7) "TABLE" or"CLUSTER"

UNIQUENESS VARCHAR2(1) NULL

COMPRESSION VARCHAR2(1) NULL

PREFIX_LENGTH NUMBER 0

TABLESPACE_NAME VARCHAR2(1) NULL

INI_TRANS NUMBER 0

MAX_TRANS NUMBER 0

INITIAL_EXTENT NUMBER 0

NEXT_EXTENT NUMBER 0

MIN_EXTENTS NUMBER 0

MAX_EXTENTS NUMBER 0

PCT_INCREASE NUMBER 0

PCT_THRESHOLD NUMBER 0

INCLUDE_COLUMN NUMBER 0

FREELISTS NUMBER 0

FREELIST_GROUPS NUMBER 0

PCT_FREE NUMBER 0

LOGGING VARCHAR2(1) NULL

BLEVEL NUMBER 0

LEAF_BLOCKS NUMBER 0

DISTINCT_KEYS NUMBER 0

AVG_LEAF_BLOCKS_PER_KEY NUMBER 0

AVG_DATA_BLOCKS_PER_KEY NUMBER 0

CLUSTERING_FACTOR NUMBER 0


NUM_ROWS NUMBER 0

SAMPLE_SIZE NUMBER 0

Appendix CALL_INDEXES

C-7

Table C-7 (Cont.) ALL_INDEXES

Name Type Value

LAST_ANALYZED DATE NULL

DEGREE VARCHAR2(1) NULL

INSTANCES VARCHAR2(1) NULL

PARTITIONED VARCHAR2(1) NULL

TEMPORARY VARCHAR2(1) NULL


SECONDARY VARCHAR2(1) NULL

BUFFER_POOL VARCHAR2(1) NULL

USER_STATS VARCHAR2(1) NULL

DURATION VARCHAR2(1) NULL

PCT_DIRECT_ACCESS NUMBER 0

ITYP_OWNER VARCHAR2(1) NULL

ITYP_NAME VARCHAR2(1) NULL

PARAMETERS VARCHAR2(1) NULL

GLOBAL_STATS VARCHAR2(1) NULL

DOMIDX_STATUS VARCHAR2(1) NULL

DOMIDX_OPSTATUS VARCHAR2(1) NULL

FUNCIDX_STATUS VARCHAR2(1) NULL

ALL_OBJECTSTable C-8 ALL_OBJECTS

Name Type Value


OBJECT_NAME VARCHAR2(256) -

SUBOBJECT_NAME VARCHAR2(1) NULL

OBJECT_ID NUMBER -

DATA_OBJECT_ID NUMBER 0

OBJECT_TYPE VARCHAR2(9) "TABLE" or "VIEW" or"INDEX" or"PROCEDURE"

CREATED DATE -

LAST_DDL_TIME DATE -

TIMESTAMP VARCHAR2(1) NULL

STATUS VARCHAR2(5) "VALID"

Appendix CALL_OBJECTS

C-8

Table C-8 (Cont.) ALL_OBJECTS

Name Type Value




ALL_TAB_COLUMNSTable C-9 ALL_TAB_COLUMNS

Name Type Value




DATA_TYPE VARCHAR2(9) -

DATA_TYPE_MOD VARCHAR2(1) NULL

DATA_TYPE_OWNER VARCHAR2(1) NULL

DATA_LENGTH NUMBER -

DATA_PRECISION NUMBER -

DATA_SCALE NUMBER -

NULLABLE VARCHAR2(1) "Y" or "N"

COLUMN_ID NUMBER(5) -

DEFAULT_LENGTH NUMBER 0

DATA_DEFAULT VARCHAR2(1) NULL

NUM_DISTINCT NUMBER 0

LOW_VALUE NUMBER 0

HIGH_VALUE NUMBER 0

DENSITY NUMBER 0

NUM_NULLS NUMBER 0

NUM_BUCKETS NUMBER 0



CHARACTER_SET_NAME VARCHAR2(1) NULL

CHAR_COL_DEC_LENGTH NUMBER 0



AVG_COL_LEN NUMBER 0

Appendix CALL_TAB_COLUMNS

C-9

Table C-9 (Cont.) ALL_TAB_COLUMNS

Name Type Value

CHAR_LENGTH NUMBER

CHAR_USED VARCHAR2(1)

V80_FMT_IMAGE VARCHAR2(1)

DATA_UPGRADED VARCHAR2(1)

HISTOGRAM VARCHAR2(1)

ALL_TAB_COMMENTSTable C-10 ALL_TAB_COMMENTS

Name Type Value




COMMENTS VARCHAR2(1) NULL

ALL_TABLESTable C-11 ALL_TABLES

Name Type Value




CLUSTER_NAME VARCHAR2(1) NULL

IOT_NAME VARCHAR2(1) NULL

PCT_FREE NUMBER 0

PCT_USED NUMBER 0

INI_TRANS NUMBER 0

MAX_TRANS NUMBER 0






FREELISTS NUMBER 0

Appendix CALL_TAB_COMMENTS

C-10

Table C-11 (Cont.) ALL_TABLES

Name Type Value



BACKED_UP VARCHAR2(1) NULL

NUM_ROWS NUMBER 0

BLOCKS NUMBER 0

EMPTY_BLOCKS NUMBER 0

AVG_SPACE NUMBER 0

CHAIN_CNT NUMBER 0

AVG_ROW_LEN NUMBER 0

AVG_SPACE_FREELIST_BLOCKS NUMBER 0

NUM_FREELIST_BLOCKS NUMBER 0



CACHE VARCHAR2(1) NULL

TABLE_LOCK VARCHAR2(1) NULL




IOT_TYPE VARCHAR2(1) NULL

TEMPORARY VARHCAR2(1) NULL


NESTED VARCHAR2(1) NULL


ROW_MOVEMENT VARCHAR2(1) NULL



DURATION VARHCAR2(1) NULL

SKIP_CORRUPT VARCHAR2(1) NULL

MONITORING VARCHAR2(1) NULL

Appendix CALL_TABLES

C-11

ALL_USERSTable C-12 ALL_USERS

Name Type Value

USERNAME VARCHAR2(256) -

USER_ID NUMBER(10) -

CREATED DATE -

ALL_VIEWSTable C-13 ALL_VIEWS

Name Type Value


VIEW_NAME VARCHAR2(256) -

TEXT_LENGTH NUMBER 0

TEXT VARCHAR2(1) -

TYPE_TEXT_LENGTH NUMBER 0

TYPE_TEXT VARCHAR2(1) -

OID_TEXT_LENGTH NUMBER 0

OID_TEXT VARCHAR2(1) -

VIEW_TYPE_OWNER VARCHAR2(1) -

VIEW_TYPE VARCHAR2(1) -

DBA_CATALOGTable C-14 DBA_CATALOG

Name Type Value




Appendix CALL_USERS

C-12

DBA_COL_COMMENTSTable C-15 DBA_COL_COMMENTS

Name Type Value





DBA_OBJECTSTable C-16 DBA_OBJECTS

Name Type Value




OBJECT_ID NUMBER -


OBJECT_TYPE VARCHAR2(9) "TABLE" or "VIEW"or "INDEX" or"PROCEDURE"

CREATED DATE -







DBA_TAB_COLUMNSTable C-17 DBA_TAB_COLUMNS

Name Type Value




Appendix CDBA_COL_COMMENTS

C-13

Table C-17 (Cont.) DBA_TAB_COLUMNS

Name Type Value






DATA_SCALE NUMBER -






LOW_VALUE NUMBER 0

HIGH_VALUE NUMBER 0

DENSITY NUMBER 0

NUM_NULLS NUMBER 0





CHAR_COL_DEC_LENGTH NUMBER 0




DBA_TAB_COMMENTSTable C-18 DBA_TAB_COMMENTS

Name Type Value





Appendix CDBA_TAB_COMMENTS

C-14

DBA_TABLESTable C-19 DBA_TABLES

Name Type Value






PCT_FREE NUMBER 0

PCT_USED NUMBER 0

INI_TRANS NUMBER 0

MAX_TRANS NUMBER 0






FREELISTS NUMBER 0




NUM_ROWS NUMBER 0

BLOCKS NUMBER 0


AVG_SPACE NUMBER 0

CHAIN_CNT NUMBER 0











Appendix CDBA_TABLES

C-15

Table C-19 (Cont.) DBA_TABLES

Name Type Value












DICT_COLUMNSTable C-20 DICT_COLUMNS

Name Type Value




DICTIONARYTable C-21 DICTIONARY

Name Type Value


COMMENTS VARCHAR2(1) -

DUALTable C-22 DUAL

Name Type Value

DUMMY VARCHAR2(1) "X"

Appendix CDICT_COLUMNS

C-16

TABLE_PRIVILEGESTable C-23 TABLE_PRIVILEGES

Name Type Value

GRANTEE VARCHAR2(256) -



GRANTOR VARCHAR2(256) -

SELECT_PRIV VARCHAR2(1) "Y"

INSERT_PRIV VARCHAR2(1) "A"

DELETE_PRIV VARCHAR2(1) "Y"

UPDATE_PRIV VARCHAR2(1) "A"

REFERENCES_PRIV VARCHAR2(1) "A"

ALTER_PRIV VARCHAR2(1) "Y"

INDEX_PRIV VARCHAR2(1) "Y"

CREATED DATE -

USER_CATALOGTable C-24 USER_CATALOG

Name Type Value



USER_COL_COMMENTSTable C-25 USER_COL_COMMENTS

Name Type Value




Appendix CTABLE_PRIVILEGES

C-17

USER_CONS_COLUMNSTable C-26 USER_CONS_COLUMNS

Name Type Value





POSITION NUMBER(5) -

USER_CONSTRAINTSTable C-27 USER_CONSTRAINTS

Name Type Value



CONSTRAINT_TYPE VARCHAR2(1) "R" or "P" or "U" or"C"


SEARCH_CONDITION VARCHAR2(1) NULL

R_OWNER VARCHAR2(256) -

R_CONSTRAINT_NAME VARCHAR2(256) -

DELETE_RULE VARCHAR2(1) NULL


DEFERRABLE VARCHAR2(1) NULL

DEFERRED VARCHAR2(1) NULL

VALIDATED VARCHAR2(1) NULL


BAD VARCHAR2(1) NULL

RELY VARCHAR2(1) NULL

LAST_CHANGE DATE -

Appendix CUSER_CONS_COLUMNS

C-18

USER_IND_COLUMNSTable C-28 USER_IND_COLUMNS

Name Type Value




COLUMN_POSITION NUMBER(3) -

COLUMN_LENGTH NUMBER -

CHAR_LENGTH NUMBER -

DESCEND VARCHAR2(4) -

USER_INDEXESTable C-29 USER_INDEXES

Name Type Value


INDEX_TYPE VARCHAR2(1) NULL



TABLE_TYPE VARCHAR2(7) "TABLE" or"CLUSTER"

UNIQUENESS VARCHAR2(1) NULL

COMPRESSION VARCHAR2(1) NULL

PREFIX_LENGTH NUMBER 0


INI_TRANS NUMBER 0

MAX_TRANS NUMBER 0






PCT_THRESHOLD NUMBER 0

INCLUDE_COLUMN NUMBER 0

FREELISTS NUMBER 0

Appendix CUSER_IND_COLUMNS

C-19

Table C-29 (Cont.) USER_INDEXES

Name Type Value


PCT_FREE NUMBER 0


BLEVEL NUMBER 0

LEAF_BLOCKS NUMBER 0

DISTINCT_KEYS NUMBER 0

AVG_LEAF_BLOCKS_PER_KEY NUMBER 0

AVG_DATA_BLOCKS_PER_KEY NUMBER 0

CLUSTERING_FACTOR NUMBER 0


NUM_ROWS NUMBER 0












PCT_DIRECT_ACCESS NUMBER 0

ITYP_OWNER VARCHAR2(1) NULL

ITYP_NAME VARCHAR2(1) NULL

PARAMETERS VARCHAR2(1) NULL


DOMIDX_STATUS VARCHAR2(1) NULL

DOMIDX_OPSTATUS VARCHAR2(1) NULL

FUNCIDX_STATUS VARCHAR2(1) NULL

Appendix CUSER_INDEXES

C-20

USER_OBJECTSTable C-30 USER_OBJECTS

Name Type Value



OBJECT_ID NUMBER -


OBJECT_TYPE VARCHAR2(9) "TABLE" or "VIEW"or "INDEX" or"PROCEDURE"

CREATED DATE -



STATUS VARCHAR2(5) "VALID"




USER_TAB_COLUMNSTable C-31 USER_TAB_COLUMNS

Name Type Value








DATA_SCALE NUMBER -






LOW_VALUE NUMBER 0

Appendix CUSER_OBJECTS

C-21

Table C-31 (Cont.) USER_TAB_COLUMNS

Name Type Value

HIGH_VALUE NUMBER 0

DENSITY NUMBER 0

NUM_NULLS NUMBER 0





CHAR_COL_DECL_LENGTH NUMBER 0




CHAR_LENGTH NUMBER 0

CHAR_USED VARCHAR2(1)

V80_FMT_IMAGE VARCHAR2(1)

DATA_UPGRADED VARCHAR2(1)

HISTOGRAM VARCHAR2(1)

USER_TAB_COMMENTSTable C-32 USER_TAB_COMMENTS

Name Type Value




USER_TABLESTable C-33 USER_TABLES

Name Type Value





PCT_FREE NUMBER 0

Appendix CUSER_TAB_COMMENTS

C-22

Table C-33 (Cont.) USER_TABLES

Name Type Value

PCT_USED NUMBER 0

INI_TRANS NUMBER 0

MAX_TRANS NUMBER 0






FREELISTS NUMBER 0




NUM_ROWS NUMBER 0

BLOCKS NUMBER 0


AVG_SPACE NUMBER 0

CHAIN_CNT NUMBER 0



















Appendix CUSER_TABLES

C-23

Table C-33 (Cont.) USER_TABLES

Name Type Value

DURATION VARCHAR2(1) NULL



USER_USERSTable C-34 USER_USERS

Name Type Value

USERNAME VARCHAR2(256) -

USER_ID NUMBER(5) -

ACCOUNT_STATUS VARCHAR2(4) "OPEN"

LOCK_DATE DATE NULL

EXPIRY_DATE DATE NULL

DEFAULT_TABLESPACE VARCHAR2(1) NULL

TEMPORARY_TABLESPACE VARCHAR2(1) NULL

CREATED DATE -

INITIAL_RSRC_CONSUMER_GROUP VARCHAR2(1) NULL

EXTERNAL_NAME VARCHAR2(1) NULL

USER_VIEWSTable C-35 USER_VIEWS

Name Type Value

VIEW_NAME VARCHAR2(256) -

TEXT_LENGTH NUMBER 0

TEXT VARCHAR2(1) -

TYPE_TEXT_LENGTH NUMBER 0

TYPE_TEXT VARCHAR2(1) NULL

OID_TEXT_LENGTH NUMBER 0

OID_TEXT VARCHAR2(1) NULL

VIEW_TYPE_OWNER VARCHAR2(1) NULL

VIEW_TYPE VARCHAR2(1) NULL

Appendix CUSER_USERS

C-24

DInitialization Parameters

The Oracle database initialization parameters in the init.ora file are distinct fromgateway initialization parameters. Set the gateway parameters in the initializationparameter file using an agent-specific mechanism, or set them in the Oracle datadictionary using the DBMS_HS package. The gateway initialization parameter file mustbe available when the gateway is started.

The following topics contain a list of the gateway initialization parameters that can beset for each gateway and their description. The topics also describe the initializationparameter file syntax.

• Initialization Parameter File Syntax

• Oracle Database Gateway for SQL Server Initialization Parameters

Initialization Parameter File SyntaxThe syntax for the initialization parameter file is as follows:

• The file is a sequence of commands.

• Each command should start on a separate line.

• End of line is considered a command terminator (unless escaped with abackslash).

• If there is a syntax error in an initialization parameter file, none of the settings takeeffect.

• Set the parameter values as follows:

[SET][PRIVATE] parameter=value

where:

parameter is an initialization parameter name. It is a string of characters startingwith a letter and consisting of letters, digits and underscores. Initializationparameter names are case sensitive.

value is the initialization parameter value. It is case sensitive. An initializationparameter value is either:

– A string of characters that does not contain any backslashes, white space ordouble quotation marks (")

– A quoted string beginning with a double quotation mark and ending with adouble quotation mark. The following can be used inside a quoted string:

* backslash (\) is the escape character

* \n inserts a new line

* \t inserts a tab

* \" inserts a double quotation mark

D-1

* \\ inserts a backslash

A backslash at the end of the line continues the string on the next line. If abackslash precedes any other character then the backslash is ignored.

For example, to enable tracing for an agent, set the HS_FDS_TRACE_LEVELinitialization parameter as follows:

HS_FDS_TRACE_LEVEL=ON

SET and PRIVATE are optional keywords. You cannot use either as an initializationparameter name. Most parameters are needed only as initialization parameters, soyou usually do not need to use the SET or PRIVATE keywords. If you do not specifyeither SET or PRIVATE, the parameter is used only as an initialization parameter forthe agent.

SET specifies that, in addition to being used as an initialization parameter, theparameter value is set as an environment variable for the agent process. Use SETfor parameter values that the drivers or non-Oracle system need as environmentvariables.

PRIVATE specifies that the initialization parameter should be private to the agentand should not be uploaded to the Oracle database. Most initialization parametersshould not be private. If, however, you are storing sensitive information like apassword in the initialization parameter file, then you may not want it uploaded tothe server because the initialization parameters and values are not encryptedwhen uploaded. Making the initialization parameters private prevents the uploadfrom happening and they do not appear in dynamic performance views. UsePRIVATE for the initialization parameters only if the parameter value includessensitive information such as a user name or password.

SET PRIVATE specifies that the parameter value is set as an environment variablefor the agent process and is also private (not transferred to the Oracle database,not appearing in dynamic performance views or graphical user interfaces).

Oracle Database Gateway for SQL Server InitializationParameters

The initialization file parameters that can be set for the Oracle Database Gateway forSQL Server are as follows:

• HS_CALL_NAME

• HS_DB_DOMAIN

• HS_DB_INTERNAL_NAME

• HS_DB_NAME

• HS_DESCRIBE_CACHE_HWM

• HS_LANGUAGE

• HS_LONG_PIECE_TRANSFER_SIZE

• HS_OPEN_CURSORS

• HS_RPC_FETCH_REBLOCKING

• HS_RPC_FETCH_SIZE

Appendix DOracle Database Gateway for SQL Server Initialization Parameters

D-2

• HS_TIME_ZONE

• HS_FDS_TRANSACTION_ISOLATION

• HS_FDS_ENCRYPT_SESSION

• HS_FDS_VALIDATE_SERVER_CERT

• HS_FDS_TRUSTSTORE_FILE

• HS_FDS_TRUSTSTORE_PASSWORD

• HS_TRANSACTION_MODEL

• IFILE

• HS_FDS_TIMESTAMP_MAPPING

• HS_FDS_DATE_MAPPING

• HS_FDS_CONNECT_INFO

• HS_FDS_PROC_IS_FUNC

• HS_FDS_RECOVERY_ACCOUNT

• HS_FDS_RECOVERY_PWD

• HS_FDS_REPORT_REAL_AS_DOUBLE

• HS_FDS_RESULTSET_SUPPORT

• HS_FDS_TRACE_LEVEL

• HS_FDS_TRANSACTION_LOG

• HS_FDS_FETCH_ROWS

• HS_IDLE_TIMEOUT

• HS_NLS_LENGTH_SEMANTICS

• HS_KEEP_REMOTE_COLUMN_SIZE

• HS_FDS_REMOTE_DB_CHARSET

• HS_FDS_SUPPORT_STATISTICS

• HS_FDS_RSET_RETURN_ROWCOUNT

• HS_FDS_SQLLEN_INTERPRETATION

• HS_FDS_ARRAY_EXEC

HS_CALL_NAME

Property Description

Default value None

Range of values Not applicable

Specifies the remote functions that can be referenced in SQL statements. The value isa list of remote functions and their owners, separated by semicolons, in the followingformat:

owner_name.function_name

Appendix DHS_CALL_NAME

D-3

For example:

owner1.A1;owner2.A2;owner3.A3

If an owner name is not specified for a remote function, the default owner namebecomes the user name used to connect to the remote database (specified when theHeterogeneous Services database link is created or taken from user session if notspecified in the DB link).

The entries for the owner names and the function names are case sensitive.

HS_DB_DOMAIN


Default value WORLD

Range of values 1 to 199 characters

Specifies a unique network sub-address for a non-Oracle system. The HS_DB_DOMAINinitialization parameter is similar to the DB_DOMAIN initialization parameter, described inthe Oracle Database Reference. The HS_DB_DOMAIN initialization parameter is requiredif you use the Oracle Names server. The HS_DB_NAME and HS_DB_DOMAIN initializationparameters define the global name of the non-Oracle system.

Note:

The HS_DB_NAME and HS_DB_DOMAIN initialization parameters must combine toform a unique address in a cooperative server environment.

HS_DB_INTERNAL_NAME


Default value 01010101

Range of values 1 to 16 hexadecimal characters

Specifies a unique hexadecimal number identifying the instance to which theHeterogeneous Services agent is connected. This parameter's value is used as part ofa transaction ID when global name services are activated. Specifying a nonuniquenumber can cause problems when two-phase commit recovery actions are necessaryfor a transaction.

HS_DB_NAME


Default value HO

Range of values 1 to 8 characters

Appendix DHS_DB_DOMAIN

D-4

Specifies a unique alphanumeric name for the data store given to the non-Oraclesystem. This name identifies the non-Oracle system within the cooperative serverenvironment. The HS_DB_NAME and HS_DB_DOMAIN initialization parameters define theglobal name of the non-Oracle system.

HS_DESCRIBE_CACHE_HWM


Default value 100

Range of values 1 to 4000

Specifies the maximum number of entries in the describe cache used byHeterogeneous Services. This limit is known as the describe cache high water mark.The cache contains descriptions of the mapped tables that Heterogeneous Servicesreuses so that it does not have to re-access the non-Oracle data store.

If you are accessing many mapped tables, increase the high water mark to improveperformance. Increasing the high water mark improves performance at the cost ofmemory usage.

HS_LANGUAGE


Default value System-specific

Range of values Any valid language name (up to 255 characters)

Provides Heterogeneous Services with character set, language, and territoryinformation of the non-Oracle data source. The value must use the following format:

language[_territory.character_set]

Note:

The globalization support initialization parameters affect error messages, thedata for the SQL Service, and parameters in distributed external procedures.

Character SetsIdeally, the character sets of the Oracle database and the non-Oracle data source arethe same. In almost all cases, HS_LANGUAGE should be set exactly the same as Oracledatabase character set for optimal character set mapping and performance. If they arenot the same, Heterogeneous Services attempts to translate the character set of thenon-Oracle data source to the Oracle database character set, and back again. Thetranslation can degrade performance. In some cases, Heterogeneous Services cannottranslate a character from one character set to another.

Appendix DHS_DESCRIBE_CACHE_HWM

D-5

Note:

The specified character set must be a superset of the operating systemcharacter set on the platform where the agent is installed.

As more Oracle databases and non-Oracle databases use Unicode as databasecharacter sets, it is preferable to also run the gateway in Unicode character set. To doso, you must set HS_LANGUAGE=AL32UTF8. However, when the gateway runs onWindows, the Microsoft ODBC Driver Manager interface can exchange data only in thedouble-byte character set, UCS2. This results in extra ratio expansion of describedbuffer and column sizes. Refer to HS_FDS_REMOTE_DB_CHARSET for instructionon how to adjust to correct sizes.

LanguageThe language component of the HS_LANGUAGE initialization parameter determines:

• Day and month names of dates

• AD, BC, PM, and AM symbols for date and time

• Default sorting mechanism

Note that Oracle does not determine the language for error messages for the genericHeterogeneous Services messages (ORA-25000 through ORA-28000). These arecontrolled by the session settings in the Oracle database.

TerritoryThe territory clause specifies the conventions for day and week numbering, defaultdate format, decimal character and group separator, and ISO and local currencysymbols. Note that the level of globalization support between the Oracle database andthe non-Oracle data source depends on how the gateway is implemented.

HS_LONG_PIECE_TRANSFER_SIZE


Default value 64 KB

Range of values Any value up to 2 GB

Sets the size of the piece of LONG data being transferred. A smaller piece size meansless memory requirement, but more round-trips to fetch all the data. A larger piece sizemeans fewer round-trips, but more of a memory requirement to store the intermediatepieces internally. Thus, the initialization parameter can be used to tune a system forthe best performance, with the best trade-off between round-trips and memoryrequirements, and network latency or response time.

Appendix DHS_LONG_PIECE_TRANSFER_SIZE

D-6

HS_OPEN_CURSORS


Default value 50

Range of values 1 to the value of Oracle's OPEN_CURSORS initialization parameter

Defines the maximum number of cursors that can be open on one connection to anon-Oracle system instance.

The value never exceeds the number of open cursors in the Oracle database.Therefore, setting the same value as the OPEN_CURSORS initialization parameter in theOracle database is recommended.

HS_RPC_FETCH_REBLOCKING


Default value ON

Range of values OFF or ON

Controls whether Heterogeneous Services attempts to optimize performance of datatransfer between the Oracle database and the Heterogeneous Services agentconnected to the non-Oracle data store.

The following values are possible:

• OFF disables reblocking of fetched data so that data is immediately sent from agentto server.

• ON enables reblocking, which means that data fetched from the non-Oracle systemis buffered in the agent and is not sent to the Oracle database until the amount offetched data is equal to or higher than the value of HS_RPC_FETCH_SIZEinitialization parameter. However, any buffered data is returned immediately whena fetch indicates that no more data exists or when the non-Oracle system reportsan error.

HS_RPC_FETCH_SIZE


Default value 50000

Range of values 1 to 10000000

Tunes internal data buffering to optimize the data transfer rate between the server andthe agent process.

Increasing the value can reduce the number of network round-trips needed to transfera given amount of data, but also tends to increase data bandwidth and to reducelatency as measured between issuing a query and completion of all fetches for thequery. Nevertheless, increasing the fetch size can increase latency for the initial fetch

Appendix DHS_OPEN_CURSORS

D-7

results of a query, because the first fetch results are not transmitted until additionaldata is available.

HS_TIME_ZONE


Default value for'[+|-]hh:mm'

Derived from the NLS_TERRITORY initialization parameter

Range of values for'[+|-]hh:mm'

Any valid datetime format mask

Specifies the default local time zone displacement for the current SQL session. Theformat mask, [+|-]hh:mm, is specified to indicate the hours and minutes before or afterUTC (Coordinated Universal Time—formerly Greenwich Mean Time). For example:

HS_TIME_ZONE = [+ | -] hh:mm

HS_FDS_ENCRYPT_SESSION


Default Value NONE

Range of values {NONE|SSL|NOTRUST_SSL}

Syntax HS_FDS_ENCRYPT_SESSION = {NONE|SSL|NOTRUST_SSL}

Specifies the way the session to SQL Server is encrypted. Valid values are:

• NONE : data transmitted between the gateway and SQL Server is not encrypted.(default).

• SSL : data transmitted between the gateway and SQL Server is encrypted usingSSL.

• NOTRUST_SSL: This option is equivalent to the SSL setting, with initializationparameter HS_FDS_VALIDATE_SERVER_CERT = DISABLED

HS_FDS_TRANSACTION_ISOLATION


Default Value READ_COMMITTED

Range of Values {READ_UNCOMMITTED|READ_COMMITTED|REPEATABLE_READ|SERIALIZABLE}

Syntax HS_FDS_ISOLATION_LEVEL={{READ_UNCOMMITTED|READ_COMMITTED|REPEATABLE_READ|SERIALIZABLE}

HS_FDS_TRANSACTION_ISOLATION specifies the isolation level that is used for thetransaction that the gateway opens on the non-Oracle database.

Appendix DHS_TIME_ZONE

D-8

The isolation levels of READ_UNCOMMITTED, READ_COMMITTED, REPEATABLE_READ, andSERIALIZABLE are the four isolation levels defined in the SQL standard and adopted byboth ANSI and ISO/IEC. For additional information regarding them, see OracleDatabase Concepts.

Use caution when specifying an isolation level lower than the Oracle transactionisolation level being used, as the gateway transaction will have different PreventableRead Phenomena from what will occur in the Oracle database transaction.

HS_FDS_TRUSTSTORE_FILE


Default Value none

Range of values path to truststore file

Syntax HS_FDS_TRUSTSTORE_FILE = path to truststore file

Specifies the path that specifies the location of the truststore file. The truststore filecontains a list of the valid Certificate Authorities (CAs) that are trusted by the clientmachine for SSL server authentication.

HS_FDS_TRUSTSTORE_PASSWORD


Default Value none

Range of values password

Syntax HS_FDS_TRUSTSTORE_PASSWORD= password

Specifies the password required to access the truststore.

HS_FDS_VALIDATE_SERVER_CERT


Default Value ENABLED

Range of values {ENABLED|DISABLED}

Syntax HS_FDS_VALIDATE_SERVER_CERT = {ENABLED|DISABLED}

Specifies whether the driver validates the certificate that is sent by the database serverwhen SSL encryption is enabled through HS_FDS_ENCRYPT_SESSION. When using SSLserver authentication, any certificate sent by the server must be issued by a trustedCertificate Authority. Valid values are:

• ENABLED : the gateway validates the certificate that is sent by the database server.Any certificate from the server must be issued by a trusted Certificate Authority inthe truststore file. The truststore information is specified using theHS_FDS_TRUSTSTORE_FILE and HS_FDS_TRUSTSTORE_PASSWORD initializationparameters.

Appendix DHS_FDS_TRUSTSTORE_FILE

D-9

• DISABLED : the gateway does not validate the certificate that is sent by thedatabase server.

HS_TRANSACTION_MODEL


Default Value COMMIT_CONFIRM

Range of Values COMMIT_CONFIRM, READ_ONLY, SINGLE_SITE,READ_ONLY_AUTOCOMMIT, SINGLE_SITE_AUTOCOMMIT

Specifies the type of transaction model that is used when the non-Oracle database isupdated by a transaction.

The following values are possible:

• COMMIT_CONFIRM provides read and write access to the non-Oracle database andallows the gateway to be part of a distributed update. To use the commit-confirmmodel, the following items must be created in the non-Oracle database:

– Transaction log table. The default table name is HS_TRANSACTION_LOG. Adifferent name can be set using the HS_FDS_TRANSACTION_LOG parameter. Thetransaction log table must be granted SELECT, DELETE, and INSERT privilegesset to public.

– Recovery account. The account name is assigned with theHS_FDS_RECOVERY_ACCOUNT parameter.

– Recovery account password. The password is assigned with theHS_FDS_RECOVERY_PWD parameter.

• READ_ONLY provides read access to the non-Oracle database.

• SINGLE_SITE provides read and write access to the non-Oracle database.However, the gateway cannot participate in distributed updates.

• READ_ONLY_AUTOCOMMIT provides read only access to the non-Oracle database thatdoes not use logging.

• SINGLE_SITE_AUTOCOMMIT provides read and write access to the non-Oracledatabase without logging. The gateway cannot participate in distributed updates.Moreover, any update to the non-Oracle database is committed immediately.

IFILE


Default value None

Range of values Valid parameter file names

Use the IFILE initialization parameter to embed another initialization file within thecurrent initialization file. The value should be an absolute path and should not containenvironment variables. The three levels of nesting limit do not apply.

Appendix DHS_TRANSACTION_MODEL

D-10

See Also:

Oracle Database Reference

HS_FDS_TIMESTAMP_MAPPING


Default Value DATE

Range of Values CHAR|DATE|TIMESTAMP

Syntax HS_FDS_TIMESTAMP_MAPPING={CHAR|DATE|TIMESTAMP}

If set to CHAR , then non-Oracle target timestamp would be mapped to CHAR(26). If setto DATE (default), then non-Oracle target timestamp would be mapped to Oracle DATE.If set to TIMESTAMP, then non-Oracle target timestamp would be mapped to OracleTIMESTAMP.

HS_FDS_DATE_MAPPING


Default Value DATE

Range of Values DATE|CHAR

Syntax HS_FDS_DATE_MAPPING={DATE|CHAR}

If set to CHAR, then non-oracle target date would be mapped to CHAR(10). If set to DATE,then non-Oracle target date would be mapped to Oracle date.

HS_FDS_CONNECT_INFO


Default Value None

Range of Values Not applicable

HS_FDS_CONNECT_INFO that describes the connection to the non-Oracle system.

The default initialization parameter file already has an entry for this parameter. Thesyntax for HS_FDS_CONNECT_INFO for the gateway is as follows:

For UNIX:

HS_FDS_CONNECT_INFO=host_name[[:port_number]|/[instance_name]][/database_name]

where, host_name is the host name or IP address of the machine hosting the SQLServer database, port_number is the port number of the SQL Server, instance_name

Appendix DHS_FDS_TIMESTAMP_MAPPING

D-11

is the instance of SQL Server running on the machine, and database_name is the SQLServer database name.

Either of the variables port_number or instance_name can be used, but not bothtogether. Optionally, they both can be omitted. The variable database_name is alwaysoptional. The slash (/) is required when a particular value is omitted. For example, allof the following entries are valid:

HS_FDS_CONNECT_INFO=host_name/instance_name/database_nameHS_FDS_CONNECT_INFO=host_name//database_nameHS_FDS_CONNECT_INFO=host_name:port_name//database_nameHS_FDS_CONNECT_INFO=host_name/instance_nameHS_FDS_CONNECT_INFO=host_name

For Windows:

HS_FDS_CONNECT_INFO= host_name/[instance_name][/database_name]

where, host_name is the host name or IP address of the machine hosting the SQLServer database, instance_name is the instance of SQL Server running on themachine, and database_name is the SQL Server database name.

Both instance_name and database_name are optional. If instance_name is omitted anddatabase_name is provided, the slash (/) is required. This can be shown as follows:

HS_FDS_CONNECT_INFO= host_name//database_name

This release supports IPv6 format, so you can enter IPv6 format in place of hostname,but you need to wrap square brackets around the IPv6 specification.

For example:

HS_FDS_CONNECT_INFO=[2001:0db8:20c:f1ff:fec6:38af]:port_number/…

HS_FDS_PROC_IS_FUNC


Default Value FALSE

Range of Values TRUE, FALSE

Enables return values from functions. By default, all stored procedures and functionsdo not return a return value to the user.

Note:

If you set this initialization parameter, you must change the syntax of theprocedure execute statement for all existing stored procedures to handlereturn values.

Appendix DHS_FDS_PROC_IS_FUNC

D-12

HS_FDS_RECOVERY_ACCOUNT


Default Value RECOVER

Range of values Any valid user ID

Specifies the name of the recovery account used for the commit-confirm transactionmodel. An account with user name and password must be set up at the non-Oraclesystem. For more information about the commit-confirm model, see theHS_TRANSACTION_MODEL parameter.

The name of the recovery account is case sensitive.

HS_FDS_RECOVERY_PWD


Default Value RECOVER

Range of values Any valid password

Specifies the password of the recovery account used for the commit-confirmtransaction model set up at the non-Oracle system. For more information about thecommit-confirm model, see the HS_TRANSACTION_MODEL parameter.

The name of the password of the recovery account is case sensitive.

HS_FDS_REPORT_REAL_AS_DOUBLE


Default Value FALSE


Enables Oracle Database Gateway for SQL Server to treat SINGLE FLOAT PRECISIONfields as DOUBLE FLOAT PPRECISION fields.

HS_FDS_RESULTSET_SUPPORT


Default Value FALSE


Enables result sets to be returned from stored procedures. By default, all storedprocedures do not return a result set to the user.

Appendix DHS_FDS_RECOVERY_ACCOUNT

D-13

Note:

If you set this initialization parameter, you must do the following:

• Change the syntax of the procedure execute statement for all existingstored procedures, to handle result sets

• Work in the sequential mode of Heterogeneous Services

HS_FDS_TRACE_LEVEL


Default Value OFF

Range of values OFF, ON, DEBUG

Specifies whether error tracing is turned on or off for gateway connectivity.

The following values are valid:

• OFF disables the tracing of error messages.

• ON enables the tracing of error messages that occur when you encounterproblems. The results are written by default to a gateway log file in LOG directorywhere the gateway is installed.

• DEBUG enables the tracing of detailed error messages that can be used fordebugging.

HS_FDS_TRANSACTION_LOG


Default Value HS_TRANSACTION_LOG

Range of Values Any valid table name

Specifies the name of the table created in the non-Oracle system for loggingtransactions. For more information about the transaction model, see theHS_TRANSACTION_MODEL parameter.

HS_FDS_FETCH_ROWS


Default Value 100

Range of Values Any integer between 1 and 1000

Syntax HS_FDS_FETCH_ROWS=num

HS_FDS_FETCH_ROWS specifies the fetch array size. This is the number of rows to befetched from the non-Oracle database and to return to Oracle database at one time.

Appendix DHS_FDS_TRACE_LEVEL

D-14

This parameter will be affected by the HS_RPC_FETCH_SIZE andHS_RPC_FETCH_REBLOCKING parameters.

HS_IDLE_TIMEOUT


Default Value 0 (no timeout)

Range of Values 0-9999 (minutes)

Syntax HS_IDLE_TIMEOUT=num

This feature is only available for Oracle Net TCP protocol. When there is no activity fora connected gateway session for this specified time period, the gateway session wouldbe terminated automatically with pending update (if any) rolled back.

HS_NLS_LENGTH_SEMANTICS


Default Value BYTE

Range of Values BYTE | CHAR

Syntax HS_NLS_LENGTH_SEMANTICS = { BYTE | CHAR }

This release of gateway has Character Semantics functionality equivalent to theOracle Database Character Semantics, that is, NLS_LENGTH_SEMANTICS. WhenHS_NLS_LENGTH_SEMANTICS is set to CHAR, the (VAR)CHAR columns of SQL Serverdatabase are to be interpreted as having CHAR semantics. The only situation thegateway does not honor the HS_NLS_LENGTH_SEMANTICS=CHAR setting is when bothOracle database and the gateway are on the same multi-byte character set

HS_KEEP_REMOTE_COLUMN_SIZE


Default Value OFF

Range of Values OFF | LOCAL | REMOTE | ALL

Syntax HS_KEEP_REMOTE_COLUMN_SIZE = OFF | LOCAL |REMOTE | ALL

Parameter type String

HS_KEEP_REMOTE_COLUMN_SIZE specifies whether to suppress ratio expansion whencomputing the length of (VAR)CHAR datatypes during data conversion from the non-Oracle database to the gateway, and then to the Oracle database. When it is set toREMOTE, the expansion is suppressed between the non-Oracle database and thegateway. When it is set to LOCAL, the expansion is suppressed between the gatewayand the Oracle database. When it is set to ALL, the expansion is suppressed from thenon-Oracle database to the Oracle database.

Appendix DHS_IDLE_TIMEOUT

D-15

When the parameter is set, the expansion is suppressed when reporting the remotecolumn size, calculating the implicit resulting buffer size, and instantiating in the localOracle database. This has effect only for remote column size from non-Oracledatabase to Oracle database. If the gateway runs on Windows andHS_LANGUAGE=AL32UTF8, then you must not specify this parameter, as it wouldinfluence other ratio related parameter operation. It has no effect for calculating ratiofor data moving from Oracle database to non-Oracle database through gateway duringINSERT, UPDATE, or DELETE.

HS_FDS_REMOTE_DB_CHARSET


Default Value None

Range of values Not applicable

Syntax HS_FDS_REMOTE_DB_CHARSET

This parameter is valid only when HS_LANGUAGE is set to AL32UTF8 and the gatewayruns on Windows. As more Oracle databases and non-Oracle databases use Unicodeas database character sets, it is preferable to also run the gateway in Unicodecharacter set. To do so, you must set HS_LANGUAGE=AL32UTF8. However, when thegateway runs on Windows, the Microsoft ODBC Driver Manager interface canexchange data only in the double-byte character set, UCS2. This results in extra ratioexpansion of described buffer and column sizes. To compensate, the gateway can re-adjust the column size if HS_FDS_REMOTE_DB_CHARSET is set to the corresponding non-Oracle database character set. For example,HS_FDS_REMOTE_DB_CHARSET=KO16KSC5601.

HS_FDS_SUPPORT_STATISTICS


Default Value TRUE

Range of values {TRUE|FALSE}

Syntax HS_FDS_SUPPORT_STATISTICS= {TRUE|FALSE}

We gather statistics from the non-Oracle database by default. You can choose todisable the gathering of remote database statistics by setting theHS_FDS_SUPPORT_STATISTICS parameter to FALSE.

HS_FDS_RSET_RETURN_ROWCOUNT


Default Value FALSE


Syntax HS_FDS_RSET_RETURN_ROWCOUNT= {TRUE|FALSE}

Appendix DHS_FDS_REMOTE_DB_CHARSET

D-16

When set to TRUE, the gateway returns the row counts of DML statements that areexecuted inside a stored procedure. The row count is returned as a single row, singlecolumn result set of type signed integer.

When set to FALSE, the gateway skips the row counts of DML statements that areexecuted inside a stored procedure. This is the default behavior, and it is the behaviorof 11.1 and older gateways.

HS_FDS_SQLLEN_INTERPRETATION


Default Value 64

Range of values {64|32}

Syntax HS_FDS_SQLLEN_INTERPRETATION= {64|32}

This parameter is only valid for 64 bit platforms. ODBC standard specifies SQLLEN (ofinternal ODBC construct) being 64 bit on 64 bit platforms, but some ODBC drivermanagers and drivers violate this convention, and implement it as 32 bit. In order forthe gateway to compensate their behavior, you need to specifyHS_FDS_SQLLEN_INTERPRETATION=32 if you use these types of driver managers anddriver.

HS_FDS_ARRAY_EXEC


Default Value TRUE


Syntax HS_FDS_ARRAY_EXEC= {TRUE|FALSE}

If set to TRUE, the gateway will use array operations for insert, update, deletestatements containing binds against the remote data source. The array size isdetermined by the value of the HS_FDS_FETCH_ROWS init parameter.

If set to FALSE, the gateway will not use array operations for insert, update, and deletestatements. Instead, a single statement will be issued for every value.

Appendix DHS_FDS_SQLLEN_INTERPRETATION

D-17

Index

AALTER statement, B-1Arithmetic operators, B-3

BBIGINT data type, A-1BINARY data type, A-1BIT data type, A-1

CCase rules, 2-9Case studies, 3-1Chained mode, 2-9CHAR data type, A-1character sets

Heterogeneous Services, D-5COMMIT

restrictions, 2-13Comparison operators, B-3CONCAT operator, 2-18CONNECT BY clause, 2-15COPY command, 2-16CREATE statement, B-1Cursor loops

restrictions, 2-13

DData definition language, B-1Data dictionary

views, C-2Data type

BIGINT, A-1BINARY, A-1BIT, A-1CHAR, A-1conversion, 2-11DATE, A-1DATETIME, A-1DECIMAL, A-1FLOAT, A-1

Data type (continued)IMAGE, A-1LONG RAW, A-1MONEY, A-1NCHAR, A-1NUMBER, A-1NUMERIC, A-1NVARCHAR, A-1RAW, A-1REAL, A-1SMALL DATETIME, A-1SMALL MONEY, A-2SMALLINT, A-2TIMESTAMP, A-2TINYINT, A-2VARBINARY, 2-17, A-2VARCHAR, A-2

DATE data type, A-1DATETIME data type, A-1DECIMAL data type, A-1DELETE statement, 3-5, B-1, B-2demonstration build SQL script, 3-2Demonstration files, 3-2Demonstration tables, 3-2Demonstration tables build SQL script, 3-2describe cache high water mark

definition, D-5DROP statement, B-1

EEncrypted format login, 2-17Error messages

error tracing, D-14Errors

ORA-02070, 2-13Executing Stored Procedures, 3-6

Ffetch array size, with HS_FDS_FETCH_ROWS,

D-14FLOAT data type, A-1Functions in SQL, 2-3

Index-1

GGateway

case studies, 3-1data dictionary tables, C-1pass-through feature, 2-2, 2-14supported functions, B-1supported SQL syntax, B-1

globalization supportHeterogeneous Services, D-5

GRANT statement, B-1Group functions, B-3

HHeterogeneous Services

defining maximum number of open cursors,D-7

optimizing data transfer, D-7setting global name, D-5specifying cache high water mark, D-5tuning internal data buffering, D-7tuning LONG data transfer, D-6

Hexadecimal notation, 2-10HS_CALL_NAME initialization parameter, D-3HS_DB_NAME initialization parameter, D-5HS_DESCRIBE_CACHE_HWM initialization

parameter, D-5HS_FDS_CONNECT_INFO, D-11HS_FDS_FETCH_ROWS parameter, D-14HS_FDS_PROC_IS_FUNC initialization

parameter, D-12HS_FDS_RECOVERY_PWD initialization

parameter, D-13HS_FDS_RESULTSET_SUPPORT initialization

parameter, D-13HS_FDS_TRACE_LEVEL initialization

parameter, D-14enabling agent tracing, D-2

HS_FDS_TRANSACTION_ISOLATIONparameter, D-8

HS_FDS_TRANSACTION_LOG initializationparameter, D-14

HS_IDLE_TIMEOUT initialization parameter,D-15

HS_KEEP_REMOTE_COLUMN_SIZEinitialization parameter, D-15

HS_LANGUAGE initialization parameter, D-5HS_LONG_PIECE_TRANSFER_SIZE

initialization parameter, D-6HS_NLS_LENGTH_SEMANTICS initialization

parameter, D-15HS_OPEN_CURSORS initialization parameter,

D-7

HS_RPC_FETCH_REBLOCKING initializationparameter, D-7

HS_RPC_FETCH_SIZE initialization parameter,D-7

HS_TIME_ZONE initialization parameter, D-8

IIFILE initialization parameter, D-10IMAGE data type, A-1Initialization parameter file

customizing, D-1INSERT statement, 3-6, B-1, B-2isolation level,

HS_FDS_TRANSACTION_ISOLATION,D-8

KKnown restrictions, 2-12

LLocking, database, 2-12LONG RAW data type, A-1

MMONEY data type, A-1

NNCHAR data type, A-1NULL values, 2-9NUMBER data type, A-1NUMERIC data type, A-1NVARCHAR data type, A-1NVL function, 3-5

OObjects, naming rules, 2-9ORA-02070, 2-13

Pparameters

gateway initialization fileHS_FDS_FETCH_ROWS, D-14HS_FDS_TRANSACTION_ISOLATION,

D-8Pass-Through Feature, 3-6Passing commands to database, 2-14Pattern Matching, B-3

Index

Index-2

PL/SQL, 2-18

RRAW data type, A-1REAL data type, A-1remote

HS_FDS_TRANSACTION_ISOLATION, D-8remote functions

referenced in SQL statements, D-3ROLLBACK

restrictions, 2-13ROWID, 2-15, 2-16

Ssavepoint support, 2-13SELECT statement, 3-6, B-2, C-1SMALL DATETIME data type, A-1SMALLINT data type, A-2SQL

statements,HS_FDS_TRANSACTION_ISOLATION,D-8

Stored procedures, 2-14, 2-18running in chained mode, 2-9

Stored procedures in SQL Server, 2-3

String functions, B-4SUM function, 3-5

TTIMESTAMP data type, A-2TINYINT data type, A-2Transaction modes, 2-9transactional capability, 2-13transactional integrity, 2-13TRUNCATE statement, B-1Two-phase commit, 2-13

UUPDATE statement, 2-16, 3-5, 3-6, B-2

VVARBINARY data type, 2-17, A-2VARCHAR data type, A-2

WWHERE CURRENT OF clause, 2-15

Index

3

server oracle® database gateway for sql user's guidethis manual describes the oracle database...

Documents