getting started with java and db2 for z/os and os/390

Peggy Abelite DB2 for z/OS and OS/390 DevelopmentIBM Corporation

Getting Started with Java and DB2 for z/OS and OS/390

Web Thread

All DB2 platforms

September 3, 2002

International DB2 Users Group

Agenda

JDBCSQLJ

Java Stored ProceduresNew Java combined client


Example customer e-business solutions

Unix

Unix

Unix

AIX

OS/390DB2

DB2 Connect

DB2 Connect

DB2 Connect

DB2 Connect

zSeries 900

Hipersockets and hypervisor

Linux Linux Linux OS/390DB2

DB2 Connect

DB2 Connect

DB2 Connect

zSeries 900

CICS OS/390DB2

zSeries 900

WebSphere EE

IMS

A

B

C


JDBC driver types - defined by Java (TM)Type 1 -- implements JDBC as a layer on top of ODBC

Type 2 -- uses native method calls (JNI) to call DLLs that issue the SQL (the DLLs are specially written for JDBC)Use Type 2 for local access (and transactional remote access)

Type 3 -- network driver that is database vendor independent

Type 4 -- network driver that speaks the database's native network protocolUse Type 4 for "network" access (non-transactional)


JDBC Example -- Select

java.sql.PreparedStatement ps = con.prepareStatement( "SELECT ADDRESS FROM

EMP WHERE NAME=?");ps.setString(1, name);java.sql.ResultSet names = ps.executeQuery();names.next();addr =names.getString(1);names.close();


JDBC Examples - Call a stored procedure CallableStatement cstmt = con.prepareCall( "CALL MYRES1(?)" ); cstmt.setBigDecimal(1, startSal); boolean rsltFlag = cstmt.execute(); if ( rsltFlag ) { queryBasic = cstmt.getResultSet(); while (queryBasic.next()) { name = queryBasic.getString(1); sal = queryBasic.getBigDecimal(2,2); System.out.println( name + " " + sal ); } queryBasic.close(); }


SQLJ OverviewStatic SQL syntax for Java

easier than JDBC, better performance too!Wide DBMS vendor acceptance

IBM, Oracle, Sybase, Tandem...SQLJ has been accepted by ANSI for inclusion in the SQL-related standards

www.sqlj.org


Why use SQLJ?Static SQL performance for Java applications

significant performance advantage over JDBC

Static SQL authorization modelprovides Java with a stronger authorization model

Productivityless code written by the application programmerresulting code is easier to maintain


Static SQLINSERT, UPDATE, DELETE, CREATE, GRANT, etc.Singleton SELECT and cursor-based SELECTcalls to stored procedures (including result sets)COMMIT, ROLLBACKmethods for CONNECT, DISCONNECT

JDBC must be used for the dynamic SQLspecs for portable Java stored procedures

What does SQLJ support?


Static SQL is associated with "program"plans/packages identify "programs" to DB2program author's table privileges are usedend users are granted EXECUTE on program

Dynamic SQL is associated with "user"no notion of "program"end users must have table privileges

BIG PROBLEM FOR A LARGE ENTERPRISE!!!

Static SQL Authorization

#sql (con) { SELECT ADDRESS INTO :addr FROM EMP WHERE NAME=:name };

SQLJ:

JDBC:java.sql.PreparedStatement ps = con.prepareStatement( "SELECT ADDRESS FROM EMP WHERE NAME=?");ps.setString(1, name);java.sql.ResultSet names = ps.executeQuery();names.next();addr = names.getString(1);names.close();

-- portable across platforms and DBMSs-- compile/bind time schema checking-- static SQL performance and authorization!!!

-- concise-- strong typing

Retrieve a single row from DB2

#sql (con) {INSERT INTO T1 VALUES( :hv1, :hv2, :hv3) };SQLJ:

JDBC:CallableStatement mystmt = con.prepareCall( "INSERT INTO T1 VALUES(?,?,?)");mystmt.setString(1,hv1);mystmt.setString(2,hv2);mystmt.setInt(3,hv3);mystmt.executeUpdate();

SQLJ example: INSERT one row

What if the table has 100 cols?


SQLJ source

class ABC {

#sql SELECT ...

}

Java source

class ABC { call "stub" }

Extracted SQL

SELECT ... host var data

Generic SQLJtranslator

Javabytecodes

Extracted SQL


Javabytecodes

Extracted SQL


DBMS-specific"stub"

Optional step:

DBMS-specificbinder

Java Compiler

Compiling an SQLJ application

JDBC "stub" JDBC "stub"

JDBC default "stub"

JDBC V6 JDBC V7 SQLJ V6 SQLJ V70

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Java API Performance Comparisons

Normalized throughput for zSeries G7 with 3 engines with 100% cache hit for JDBC.SQLJ advantage increased from 20% to 35% when Java overhead was reduced.

+20%

+35%


Java Stored ProceduresSQLJ Part 1 specification

Output parameters are single-element arraysBecause Java doesn't allow modifying parms

Result sets are not in catalog definitionResult sets are in method signature as outputs

Because "with return" is not universalCan be JDBC, SQLJ, or both

Compiled Java on V5 and V6JAR files support in V7


V7: Built-in Utility Stored ProceduresAs per SQLJ specificationInvoked with CALL statement

INSTALL_JAR (file URL)Installs the Java ARchive file into the DB2 catalogJAR file contains one or more Stored Procedures

REPLACE_JARREMOVE_JAR

new JAR authorizationGRANT USAGE ON JAR


Tasks for OS/390 System ProgrammerSet up WLM environment, address space JCLInstall IBM S/390 JDK w/enhancementInstall JDBC/SQLJ driver

Run db2genJDBC to generate DBRMs and bind into DB2 package

-OR- use default .ser file with V7 driverSet up JAVAENV with "home" dirsProvide .profile for users


JAVAENV DD CARD(in WLM address space JCL)

Dataset containing RUNOPTSApplies to entire WLMENV, not individual SPs

Must set JAVA_HOMEIBM JDK 1.3.1 (persistent reusable technology)

Must set DB2_HOMEJDBC/SQLJ driver directory

Can set CLASSPATHdirectory for user classes not in JARall SP classes are shared

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Java- JDBCJava - SQLJC - static

Stored Procedure Performance by Language


What is DB2 Common Client?

Reengineering of DB2 Connect and CAEImproved DB2 Connect and CAE consistency/performance

much higher percentage of common codeDRDA Improvements

external capabilitiesinternal performance improvements

Scrollable cursors

????


Objectives for new Java ClientSingle driver for Unix, Windows, and OS/390

eliminate major cause of Java porting problems

Improved Java driver integration with DB2Simplify install/deployment of Type 2 driverImprove JDBC and SQLJ performance

SQLJ is now faster than JDBC on Unix/Windows


DB2 Java Client Architecture

Common Code for all drivers:JDBC APIsSQLJ APIs

Type 4 DriverType 2 driver

for Unix/Windows

Type 2 driver for

OS/390 or z/OS

DRDA overTCP/IP

RRS Attach

(Any DB2 server)

Local SQL API XA Support


New function in new Java Client

Type 4 driver for thin clientsProvide fully compliant JDBC 2.0 driverTrace improvements

dynamically turn trace on/offmultiple levels of trace detail

Provide 100% Java application development process for SQLJ


OS/390DB2

Java program

Configuration D

JCC: Type 4 Driver support

Network applet driverCharacter conversion is optional

performance small download footprint


DB2's type 4 JDBC driverTargeted at clients that fit this profile:

prefer to not install the JDBC driver on their machinedon't need high-end performance/scalability/availability

The type 4 driver will NOT support:JTA (2--phase commit)parallel sysplex workload balancingconnection concentrator functionalitystatic SQL profilingQuery Patrollersome of the performance optimizations in the type 2 driverfull range of code page translations

If you are trying to support EJBs or high-end application servers, you should use the type 2 JDBC driver.


New Java API Enhancements

Scrollable cursor support Improved security for DB2 authenticationJava API for Set Client Information (SQLESETI)Improved Java SQL error informationNative DB2 server SQL error messagesConnection pooling improvements


Scrollable Cursor Support

Java Application

JavaDriver

DB2 Server-- Exploits DB2 engine scrolling-- Supports update operations-- Java driver performs "local" scrolling within a block of data-- minimizes network traffic

Current row

QueryResult


Java API for Set Client InformationFor DB2 for Unix and Windows users:

provides additional monitoring informationFor DB2 for OS/390 and z/OS users:

provides additional monitoring informationall four strings are included in all IFC records

Allows you to search accounting records or other IFC records for data related to a particular Java user or application.

the last two strings can be used for WLM prioritization of the Java connections to DDF


Improved SQL Error Information

DB2Diagnosable class for reporting contents of the SQLCA and SQL error message text

getSQLCode()getSQLErrmc()getSQLErrp()getSQLErrd()getSQLState()getSQLWarn()

getSQLErrorMessage() Information is accessible for both JDBC and SQLJ whenever an SQL exception is thrown


Native DB2 Server SQL Error Messages

"Error Message" stored procedures are provided by each DB2 server (including DB2 for OS/390 V6 and V7)Allows DB2 client to return "native" error message text for the target DB2 serverNative error message is only returned when explicitly requested

getSQLErrorMessage()


SQLJ Application Development Process(BIG improvements !)

100% Java application process eliminates DBRM files and .bnd files

New SQLJ serialized profile formatfully portable to all platforms -- user can deploy on any server platform without running db2profc on the target system.contains information needed for all BIND operations, without having to recustomize on each BINDmigration path for old SQLJ serialized profiles to the new format

Simplifies deployment of applications, but does require changes in existing procedures used by SQLJ users.


Summary

JDBC Driver TypesRemember what Type 4 is designed for

SQLJ - static SQL for a dynamic worldJava stored proceduresNew combined client for all platforms

Code portability

getting started with java and db2 for z/os and os/390

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