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Module 3: Teradata Basics

After completing this module, you will be able to:

List and describe the major components of the Teradata

architecture.

Describe how the components interact to manage

incoming and outgoing data

List 5 types of Teradata database objects

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Teradata Storage Architecture

Notes:

The Parsing Engine dispatches

request to insert a row.

The Message Passing Layer

insures that a row gets to the

appropriate AMP (Access Module

Processor).

The AMP stores the row on its

associated (logical) disk.

An AMP manages a logical or

virtual disk which is mapped to

multiple physical disks in a disk

array.

Teradata

AMP 4AMP 3AMP 1 AMP 2

Parsing

Engine(s)

Message Passing Layer

18

25

4 41

129

075

80

3

26

672

5

Records From Client (in random sequence)

2 32 67 12 90 6 54 75 18 25 80 41

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Teradata Retrieval Architecture

Notes:

The Parsing Engine dispatches a

request to retrieve one or more

rows.

The Message Passing Layer

insures that the appropriate

AMP(s) are activated.

The AMP(s) locate and retrieve

desired row(s) in parallel access.

Message Passing Layerreturns to

retrieved rows to PE.

The PE returns row(s) to

requesting client application.

Teradata

AMP 4AMP 3AMP 1 AMP 2

Parsing

Engine(s)


18

25

4 41

129

075

80

3

26

672

5

Rows retrieved from table

2 32 67 12 90 6 54 75 18 25 80 41

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Multiple Tables on Multiple AMPs

EMPLOYEE Rows

DEPARTMENT RowsJOB Rows

EMPLOYEE Table DEPARTMENT Table JOB Table

Parsing Engine

AMP #1 AMP #2 AMP #3 AMP #4


Notes:

Some rows from each table may

be found on each AMP.

Each AMP may have rows from

all tables.

Ideally, each AMP will hold

roughly the same amount of

data.

EMPLOYEE Rows


EMPLOYEE Rows


EMPLOYEE Rows


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Linear Growth and Expandability

AMP

AMP

ParsingEngine

AMP

SESSIONS

PARALLEL

PROCESS

ING

DATA

Disk

Disk

Disk

Parsing

Engine

Parsing

EngineNotes:

Teradata is a linearlyexpandable RDBMS.

Components may be added asrequirements grow.

Linear scalability allows forincreased workload without

decreased throughput.

Performance impact of addingcomponents is shown below.

USERS AMPs DATA Performance

Same Same Same Same

Double Double Same Same

Same Double Double Same

Same Double Same Double

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Teradata Objects

There are eight types of objects which may be found in a Teradata database/user.

Tables rows and columns of dataViews predefined subsets of existing tables

Macros predefined, stored SQL statements

Triggers SQL statements associated with a table

Stored Procedures program stored within Teradata

Join and Hash Indexes separate index structures stored as objects within a database

Permanent Journals table used to store before and/or after images for recovery

DEFINITIONS OF

ALL DATABASE

OBJECTS

DD/D

These objects are created,

maintained and deleted using

Structured Query Language (SQL).

Object definitions are stored in theData Dictionary / Directory (DD/D).

DATABASE or USER

TABLE 2 TABLE 3TABLE 1

VIEW 2 VIEW 3VIEW 1

MACRO 2 MACRO 3MACRO 1

TRIGGER 2 TRIGGER 3TRIGGER 1

Stored Procedure 1 Stored Procedure 2 Stored Procedure 2

Join/Hash Index 1 Join/Hash Index 2 Join/Hash Index 3

Permanent Journal These aren't directly accessed by users.

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The Data Dictionary Directory (DD/D)

The DD/D ...

is an integrated set of system tables

contains definitions of and information about all objects in the system

is entirely maintained by the RDBMS

is data about the data or metadata

is distributed across all AMPs like all tables

may be queried by administrators or support staff

is accessed via Teradata supplied views

Examples of DD/D views:

DBC.Tables - information about all tables

DBC.Users - information about all users

DBC.AllRights - information about access rights

DBC.AllSpace - information about space utilization

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Structured Query Language (SQL)

SQL is a query language for Relational Database Systems.

A fourth-generation language A set-oriented language A non-procedural language

(e.g, doesnt have IF, GO TO, DO, FOR NEXT, or PERFORM statements)

SQL consists of:

Data Definition Language (DDL)

Defines database structures (tables, users, views, macros, triggers, etc.)

CREATE DROP ALTER

Data Manipulation Language (DML)

Manipulates rows and data values

SELECT INSERT UPDATE DELETE

Data Control Language (DCL)

Grants and revokes access rights

GRANT REVOKE

Teradata SQL also includes Teradata Extensions to SQLHELP SHOW EXPLAIN CREATE MACRO

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CREATE TABLE Example of DDL

CREATE TABLE Employee

,FALLBACK(employee_number INTEGER NOT NULL

,manager_emp_number INTEGER

,dept_number SMALLINT

,job_code INTEGER COMPRESS

,last_name CHAR(20) NOT NULL

,first_name VARCHAR (20)

,hire_date DATE FORMAT 'YYYY-MM-DD'

,birth_date DATE FORMAT 'YYYY-MM-DD'

,salary_amount DECIMAL (10,2)

)

UNIQUE PRIMARY INDEX (employee_number)

,INDEX (dept_number);

Other DDL Examples

CREATE INDEX (job_code) ON Employee ;

DROP INDEX (job_code) ON Employee ;

DROP TABLE Employee ;

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Views

Views are pre-defined subsets of existing tables consisting of specified

columns and/or rows from the table(s).

A single table view:

is a window into an underlying table

allows users to read and update a subset of the underlying table

has no data of its own

MANAGER

EMPLOYEE EMP DEPT JOB LAST FIRST HIRE BIRTH SALARY

NUMBER NUMBER NUMBER CODE NAME NAME DATE DATE AMOUNT

1006 1019 301 312101 Stein John 861015 631015 3945000

1008 1019 301 312102 Kanieski Carol 870201 680517 3925000

1005 0801 403 431100 Ryan Loretta 861015 650910 4120000

1004 1003 401 412101 Johnson Darlene 861015 560423 46300001007 1005 403 432101 Villegas Arnando 870102 470131 5970000

1003 0801 401 411100 Trader James 860731 570619 4785000

EMPLOYEE (Table)

PK FK FK FK

EMP NO DEPT NO LAST NAME FIRST NAME HIRE DATE

1005 403 Villegas Arnando 870102

801 403 Ryan Loretta 861015

Emp_403 (View)

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Multi-Table Views

A multi-table view allows users to access data from multiple tables as if it were in a single

table. Multi-table views are also called join views. Join views are used for reading only,not updating.

EMPLOYEE (Table)

1006 1019 301 312101 Stein John 861015 631015 39450001008 1019 301 312102 Kanieski Carol 870201 680517 3925000

1005 0801 403 431100 Ryan Loretta 861015 650910 4120000

1004 1003 401 412101 Johnson Darlene 861015 560423 4630000

1007 1005 403 432101 Villegas Arnando 870102 470131 5970000

1003 0801 401 411100 Trader James 860731 570619 4785000

MANAGER



PK FK FK FK

MANAGER

DEPT DEPARTMENT BUDGET EMPNUMBER NAME AMOUNT NUMBER

501 marketing sales 80050000 1017

301 research and development 46560000 1019

302 product planning 22600000 1016

403 education 93200000 1005

402 software support 30800000 1011

401 customer support 98230000 1003

201 technical operations 29380000 1025

PK FK

DEPARTMENT (Table)

LAST DEPARTMENT

NAME NAME

Stein research & development

Kanieski research & development

Ryan education

Johnson customer support

Villegas education

Trader customer support

EmpDept (View)

"Joined Together"

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SELECT Example of DML

The SELECT statement is used to retrieve data from tables.

Who was hired on October 15, 1986?

1006 1019 301 312101 Stein John 861015 631015 3945000

1008 1019 301 312102 Kanieski Carol 870201 680517 3925000

1005 0801 403 431100 Ryan Loretta 861015 650910 4120000

1004 1003 401 412101 Johnson Darlene 861015 560423 4630000


1003 0801 401 411100 Trader James 860731 570619 4785000

EMPLOYEE (partial listing)

MANAGER



PK FK FK FK

SELECT Last_Name

,First_Name

FROM Employee

WHERE Hire_Date = '1986-10-15'

;

Result

LAST

NAME

Stein

Ryan

Johnson

FIRST

NAME

John

Loretta

Darlene

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The JOIN Operation

A join operation is used when the SQL query requires information from multiple

tables.Who works in Research and Development?

EMPLOYEE

1006 1019 301 312101 Stein John 861015 631015 39450001008 1019 301 312102 Kanieski Carol 870201 680517 3925000

1005 0801 403 431100 Ryan Loretta 861015 650910 4120000

1004 1003 401 412101 Johnson Darlene 861015 560423 4630000


1003 0801 401 411100 Trader James 860731 570619 4785000

MANAGER



PK FK FK FK

MANAGER

DEPT DEPARTMENT BUDGET EMPNUMBER NAME AMOUNT NUMBER

501 marketing sales 80050000 1017

301 research and development 46560000 1019

302 product planning 22600000 1016

403 education 93200000 1005

402 software support 30800000 1011

401 customer support 98230000 1003201 technical operations 29380000 1025

PK FK

DEPARTMENTResult

LAST

NAME

Stein

Kanieski

FIRST

NAME

John

Carol

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Macros Teradata SQL Extension

A MACRO is a predefined set of SQL statements which is logically stored in a database.

Macros may be created for frequently occurring queries of sets of operations.

Macros have many features and benefits:

Simplify end-user access

Control which operations may be performed by users

May accept user-provided parameter values

Are stored on the RDBMS, thus available to all clients

Reduces query size, thus reduces LAN/channel traffic

Are optimized at execution time

May contain multiple SQL statements

To create a macro:

CREATE MACRO Customer_List AS (SELECT customer_name FROM Customer;);

To execute a macro:

EXEC Customer_List;

To replace a macro:

REPLACE MACRO Customer_List AS(SELECT customer_name, customer_number FROM Customer;);

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HELP Commands Teradata SQL Extension

Databases and Users:

HELP DATABASE Customer_Service ;

HELP USER Dave_Jones ;

Tables, Views, and Macros:

HELP TABLE Employee ;

HELP VIEW Emp;

HELP MACRO Payroll_3;

HELP COLUMN Employee.*;

Employee.last_name;

Emp.* ;

Emp.last;

HELP INDEX Employee;

HELP STATISTICS Employee;HELP CONSTRAINT Em lo ee.over 21;

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Example of HELP DATABASE

HELP DATABASE Customer_Service;

*** Help information returned. 15 rows.

*** Total elapsed time was 1 second.

Table/View/Macro name Kind Comment

Contact T ?Customer T ?

Cust_Comp_Orders V ?

Cust_Pend_Orders V ?

Cust_Order_ix I ?

Department T ?

Employee T ?

Employee_Phone T ?Job T ?

Location T ?

Location_Employee T ?

Location_Phone T ?

Orders T ?

Set_Ansidate_on M ?Set_Integerdate_on M ?

Command:

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SHOW Command Teradata SQL Extension

SHOW commands display how an object was created.

Command Returns statement

SHOW TABLE tablename; CREATE TABLE statement

SHOW VIEW viewname; CREATE VIEW ...

SHOW MACRO macroname; CREATE MACRO ...

SHOW TRIGGER triggername; CREATE TRIGGER

SHOW PROCEDURE procedurename; CREATE PROCEDURE

SHOW TABLE Employee;

CREATE SET TABLE CUSTOMER_SERVICE.Employee, FALLBACK,

NO BEFORE JOURNAL,

NO AFTER JOURNAL,

CHECKSUM = DEFAULT

(employee_number INTEGER,

manager_employee_number INTEGER,

department_number INTEGER,

job_code INTEGER,

:

salary_amount DECIMAL(10,2) NOT NULL)UNIQUE PRIMARY INDEX ( employee_number );

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EXPLAIN Facility Teradata SQL Extension

The EXPLAIN modifier in front of any SQL statement generates an English translation of

the Parsers plan.The request is fully parsed and optimized, but not actually executed.

EXPLAIN returns:

Text showing how a statement will be processed (a plan)

An estimate of how many rows will be involved

A relative cost of the request (in units of time)This information is useful for:

predicting row counts

predicting performance

testing queries before production

analyzing various approaches to a problem EXPLAIN

EXPLAIN SELECT last_name, department_number FROM Employee ;

Explanation (partial):

3) We do an all-AMPs RETRIEVE step from CUSTOMER_SERVICE.Employee by way of an all-rows

scan with no residual conditions into Spool 1, which is built locally on the AMPs. The size ofSpool 1 is estimated to be 24 rows. The estimated time for this step is 0.15 seconds.

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Teradata Features Review

Designed for decision-support and tactical queries

Ideal for data warehouse applications

Parallelism makes possible access to very large tables

Performance increase is linear as components are added

Uses standard SQL

Runs as a database server to client applications Runs on multiple hardware platforms

Open architecture uses industry standard components

Win XPWin 2000

UNIX

Client

Mainframe

Client

Teradata

DATABASE

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Review Questions

1. What language is used to access a Teradata table?

2. What are five Teradata database objects?

3. What are four major components of the Teradata architecture?

4. What are views?

5. What are macros?

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Module 3: Review Question Answers

1. What language is used to access a Teradata table?

2. What are five Teradata database objects?

3. What are four major components of the Teradata architecture?

4. What are views?

5. What are macros?

SQL

Tables, views, macros, triggers, and stored procedures

PE, AMPs, Vdisks, and Message Passing Layer

- Subset of rows and columns or one or more tables

- Virtual tables

- Window into one or more tables

Predefined stored set of SQL statements

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