Unit Objectives After completing this unit, you should be able to:

Transcription

1 DB2 Concepts

2 Unit Objectives After completing this unit, you should be able to: Identify DB2 family products Explain DB2 workstation component functions Identify DB2 objects Discuss the concepts of relational tables and DB2's implementation of referential integrity Define a unit of recovery and detail the basic locking strategies used by DB2 Identify the key differences between static SQL and other application alternatives for accessing DB2 data Describe the concept of a universal client Identify DB2's role in X/OPEN

3 DB2 Family UNIX Systems Intel Systems DB2 DB2 S/390, S/370 DB2 for OS/390 DB2 for VSE and VM DB2 for OS/400 AS/400

4 DB2 UDB - The Scalable DB Massively Parallel Processor (MPP) DB2 UDB Cluster Enterprise-Extended Edition Enterprise Edition Workgroup Edition Personal Edition Satellite Edition

5 DB2 Product Components DRDA Application Requester Administration Client Run-Time Client Application Development Client Communication Support DB2 DB2 Connect DB2 Relational Connect (EE or EEE) DRDA Application Server Oracle Database

6 Connecting to DB2 UDB Database Servers DB2 Personal Developer's Edition (PDE) includes: DB2 Personal Edition Run-Time Client includes: Workgroup Edition DB2 Connect Personal Edition Application Development Client ODBC support Command Line Processor (CLP) Enterprise Edition Administration Client JDBC support Enterprise- Extended Edition Extenders Netscape Communicator DB2 Product Information

7 Accessing DB2 Command Line Processor Commands Interactive SQL Administration Tools Control Center Command Center Alert Center Script Center Event Analyzer Journal Tools Settings Applications APIs Embedded SQL Call Level Interface JAVA SQL/API Database Engine

8 End-User Access Application Analyst END USER Application Programmer (I/C Consultant) Query Tool DBA Systems Programmer DATA BASE

9 Physical Environment DB2 Product INSTANCE_1 INSTANCE_2 CATALOG LOG DB_1 DB CONFIG FILE_1 &$7$/2* /2* DB_3 DB CONFIG FILE_3 JOIN CATALOG LOG DB_2 DB CONFIG FILE_2 &$7$/2* /2* DB_4 DB CONFIG FILE_4 DBM CONFIG FILE_1 DBM CONFIG FILE_2

10 Connect to Database Application Requestor Application Server CONNECT TO dbname USER userid USING password database

11 DB2 Object Hierarchy Instance 1 dbm configuration file Catalog Catalog Database 1 Log Database 2 DB configuration file Log DB config. file Table1 Table2 Table3 Table2 Index1 View1 View1 Index1 BLOBs View2 Index2 View3

12 View BASE TABLE AS IT EXISTS ON STORAGE VIEW AS THE PROGRAM's LOGIC SEES IT A B C D B C

13 Application Alternatives Static SQL Dynamic SQL REXX Call Level Interface ODBC OLE DB Java Development JDBC and SQLJ Stored Procedures User-Defined Functions Application Programming Interfaces (APIs) Distributed Transaction Processing

14 Static Embedded SQL Source code with SQL Table/Column Descriptions PREPARE Authorizations Statistics Package Package: Contains SQL statements optimized according to database statistics

15 Static SQL Vacation Travel Booking Vacation Code: Origination: Travel Date: Name: Charge Card: Telephone: Exp. Date: SQL statements prepared during application development

16 Dynamic SQL Vacation Travel Unlimited Type: Destination: Country: Language: Activities: Cooking, Laundry, Household: Number Traveling: Mode of Transportation: Cost: State: Date: SQL statements prepared during application execution

17 REXX Applications REXX is an interpreted language; no precompiler is used All SQL is processed dynamically DB2 APIs are used to create DB2 applications SQLEXEC - supports the SQL language SQLDBS - supports command-like versions of DB2 APIs SQLDB2 - supports a REXX-specific interface to the command line processor

18 Call Level Interface CLI versus Dynamic SQLPrepare(...); SQLExecute(...); SQLFetch(...); SQL statements prepared during application execution EXEC SQL PREPARE... EXEC SQL EXECUTE... EXEC SQL FETCH..... Prepare Prepare Execute DB2 or Other RDBMS DB2 Execute

19 ODBC (Open Database Connectivity) X/OPEN SAG CLI ODBC Microsoft

20 Heterogeneous Data Access - OLE DB OLE DB Consumer Support (Windows Only) Ability to use any OLE DB data source as a Read Only DB2 table OLE DB sources include MS Access, MS SQL Server, and so forth Ability to move data from OLE table into DB2 table Join OLE tables with DB2 tables Ability to retrieve and manipulate data using SQL language DB2 client DB2 client DB2 OLE DB consumer parameters OLEDB OLE DB provider Source Data Virtual Table

21 Java Applications SQLJ Application SQLJ Run-Time Classes Remote Database Java Application JDBC DB2 Client

22 DB2 Java Applets Web Browser Web Server Host SQLJ Applet SQLJ Run-Time Classes HTTP JDBC Server CLI HTTPd Local DB2 Database Java/ JDBC Applet JDBC Client TCP/IP Socket Remote DB2 Database

23 JDBC Support DB2 provides support for: Java applications Which requires DB2 Run-time Client Java applets No DB2 component code on the client Java servlets UDF's and stored procedures Using Java Development Kit (JDK) Version 1.1 or higher Includes Java Database Connectivity (JDBC) API from SUN Microsystems

24 SQLJ Support SQLJ application, servlet, and applet support for JAVA running on Windows and UNIX Static SQL INSERT, UPDATE, DELETE, CREATE, GRANT and so forth Singleton and cursor-based SELECT Calls to stored procedures (including result sets) COMMIT, ROLLBACK Methods for CONNECT and DISCONNECT Static SQL can be faster JDBC must be used for dynamic SQL

25 Comparing JDBC and SQLJ SQLJ: Extends Java to support static SQL constructs Complements JDBC dynamic SQL API model Similar considerations and trade-offs as in other languages: Static versus dynamic Dynamic is flexible at run time Building SQL on the fly requires dynamic access Pre-compilation of SQLJ-based code Type-checking performed against the database during development Simplifies task for programmer: Less source code Translator handles most of the work for the programmer Simplified rules for calling Stored Procedures and functions

26 Stored Procedures Client Application Run-Time Client DB2 Server DB2 Database Network Client Application Run-Time Client Stored Procedure DB2 Server DB2 Database

27 Stored Procedure Builder Development of DB2 stored procedures made simple Supports development and debugging of Java stored procedures on all DB2 UDB Server platforms Supports static (SQLJ), dynamic (JDBC) SQL and SQL Procedure Language GUI development environment Users can focus on the logic of their SPs Wizards simplify many tasks Tool automates build process Integrated with MS Visual Studio Benefits: Ease of development Portability across DB2 family

28 Stored Procedure Builder Example Follow steps in Stored Procedure Wizard to construct a new Java SP

29 User-Defined Functions SELECT EURO(SALARY) FROM EMP DB2 Server EURO Conversion Function DB2 Database Functions EURO Convert! EURO

30 Database Manager APIs API - Start Database Manager Create Database Backup Database Bind... SQL - Select Insert Update...

31 X/Open XA Support for Distributed Transaction Processing Application Program (AP) (1) (2) Resource Managers (RMs) (3) Transaction Manager (TM)

32 Referential Integrity (1 of 3) Some Basic Terms PRIMARY KEY Parent Table DEPT DEPTNAME C01 INFORMATION CENTER... E11 OPERATIONS PARENT DEPARTMENT table KEY PRIMARY KEY FOREIGN KEY UNIQUE CONSTRAINT Dependent Table EMP FIRSTNM LASTNM... DEPT... TAX_ID SALLY KWAN... C EILEEN HENDERSON... E DOLORES QUINTANA... C JOHN PARKER... E PHILIP SMITH... E EMPLOYEE table

33 Referential Integrity (2 of 3) By definition, a FOREIGN KEY in one table matches a PARENT KEY A PARENT KEY value must be UNIQUE, and cannot be NULL A FOREIGN KEY value must match a PARENT KEY or be NULL DB2 enforcement of referential constraints: INSERT/UPDATE/LOAD of FOREIGN KEY Must match PARENT KEY or be NULL UPDATE of PARENT KEY Not allowed if any FOREIGN KEYS match original value

34 Referential Integrity (3 of 3) DELETEing a row When DELETEing a parent key, what should be done to matching foreign keys? DELETE rows with matching values (CASCADE) Change matching values to null (SET NULL) Disallow the DELETE if matching values exist (RESTRICT / ACTION)

35 Referential Structure TABLES LINKED BY REFERENTIAL CONSTRAINTS RESTAURANTS.NAME C N R RATINGS PALS DISCOUNT_ TICKETS.PLACE.FAVOR.NAME

36 DELETE Rules Exercise ROWS 1 THROUGH 15 CONTAIN THE FOLLOWING RESTAURANT NAMES: RESTAURANTS.NAME RATINGS.PLACE PALS.FAVOR DISCOUNT_TICKETS.NAME ALDO V&T HORN 4SEAS ALDO V&T ALDO 4SEAS V&T V&T V&T ALDO 4SEAS 15 ALDO PARENT C N R WHAT IS THE EFFECT OF THE REQUEST TO DELETE: RESTAURANTS RATINGS PALS DISCOUNT TICKETS ROW ROW ROW ROW

37 SQL DDL DATA DEFINITION LANGUAGE CREATE ALTER DROP COL1 COL2 COL3 NEW

38 SQL DML DATA MANIPULATION LANGUAGE EMP SALARY NAME SELECT UPDATE INSERT ANDREW SMITH JONE CARTER FREED ANGELO DELETE

39 SQL DCL DATA CONTROL LANGUAGE REVOKE GRANT CONNECT COMMIT ROLLBACK

40 Locking Strategies Table Table OR Row(s) Table Space DB2 employs either strict Table Locking or Table Locking in conjunction with Row Locking for typical Application Processing

41 Table Lock Modes IS Intent Share IX Intent exclusive SIX Share with Intent exclusive S Share U Update Row Locking also used (See next page) IN Intent None X exclusive Z superexclusive Strict Table Locking

42 Row Lock Modes Row Lock S Share IS U Update IX X exclusive IX W Weak exclusive IX NS Next key Share IS NX Next key exclusive IX NW Next key Weak exclusive IX An application does not acquire Row locks If it is using Table Locks of S, U, X, or Z Minimum* Supporting Table Lock

43 SELECT UPDATE Table Lock versus Row Locking Lock Table Update WAIT

44 Lock Mode Compatibility U NS W MODE OF LOCK B MODE OF LOCK A IN IS S IX SIX U X Z Table Locks MODE OF LOCK B LOCK A MODE S U X W NS NX NW Row Locks IS S IX IN NX X S NW SIX U X Z

45 Some Scenarios GARAGE BR BATH B'FAST FAMILY MASTER BR KITCHEN BATH DINING LIVING CLOSET BATH BR STOPLETT CONSTRUCTION

46 Unit of Recovery SAVINGS CHECKING POINT OF CONSISTENCY BANK TRANSFER NEW POINT OF CONSISTENCY OLD DATA DATA UPDATES UNIT OF RECOVERY COMMIT UPDATED DATA OLD DATA POINT OF CONSISTENCY DATA UPDATES TERMINATION BACK OUT UPDATES NEW POINT OF CONSISTENCY OLD DATA ABORT END ABORT RECOVERY IS TO LAST POINT OF CONSISTENCY

47 Commit and Rollback Operates on a "Unit of Recovery" COMMIT Changes will be made Row Locks released Certain Table Locks released ROLLBACK Changes backed out All Locks released

48 Commit versus Rollback COMMIT ROLLBACK UNIX or OS/2 Windows CICS Normal prog. term. EXEC SQL COMMIT EXEC SQL COMMIT Normal trans. term. SYNC POINT cmd. Prog. abend EXEC SQL ROLLBACK Program termination (normal or abend) EXEC SQL ROLLBACK Trans. abend SYNCPOINT ROLLBACK cmd ABEND cmd

49 Data Recovery (1 of 2) Backup Database Updated Database (failure) "COMMIT" "UPDATE" "UPDATE" LOG

50 Data Recovery (2 of 2) Backup UTILITY Restore Recovered Database "UPDATE" LOG

51 CLP Syntax db2 option-flag db2-command sql-statement? phrase message sql-state class-code

52 Starting a CLP Session non-interactive mode db2 connect to eddb db2 "select * from syscat.tables" more (double quotes may be required) interactive mode db2 db2=> connect to eddb db2=> select * from syscat.tables

53 Command Center

54 QUIT versus TERMINATE versus CONNECT RESET CLP COMMAND Terminate CLP Back-end Process Disconnect database Connection quit No No terminate Yes Yes connect reset No Yes if CONNECT=1 (RUOW)

55 Unit Summary Since completing this unit, you should be able to: Identify DB2 family products Explain DB2 workstation component functions Identify DB2 objects Discuss the concepts of relational tables and DB2's implementation of referential integrity Define a unit of recovery and detail the basic locking strategies used by DB2 Identify the key differences between static SQL and other application alternatives for accessing DB2 data Describe the concept of a universal client Identify DB2's role in X/OPEN