Application Programming and SQL Guide - Kmlinux

|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
#
Defining a parent key and a unique index . . . . . . . . . . . . . 254
Defining a foreign key . . . . . . . . . . . . . . . . . . . . . 256
Referential constraints on tables with multilevel security with row-level
granularity . . . . . . . . . . . . . . . . . . . . . . . . 258
Using informational referential constraints . . . . . . . . . . . . . . 259
Chapter 11. Using DB2-generated values as keys . . . . . . . . . . 261
Using ROWID columns as keys . . . . . . . . . . . . . . . . . . 261
Defining a ROWID column . . . . . . . . . . . . . . . . . . . 261
Direct row access . . . . . . . . . . . . . . . . . . . . . . 262
Using identity columns as keys . . . . . . . . . . . . . . . . . . 262
Defining an identity column . . . . . . . . . . . . . . . . . . . 263
Parent keys and foreign keys . . . . . . . . . . . . . . . . . . 264
Using values obtained from sequence objects as keys . . . . . . . . . . 265
Creating a sequence object . . . . . . . . . . . . . . . . . . . 265
Referencing a sequence object . . . . . . . . . . . . . . . . . 266
Keys across multiple tables . . . . . . . . . . . . . . . . . . . 266
Chapter 12. Using triggers for active data . . . . . . . . . . . . . 269
Example of creating and using a trigger . . . . . . . . . . . . . . . 269
Parts of a trigger . . . . . . . . . . . . . . . . . . . . . . . . 271
Trigger name . . . . . . . . . . . . . . . . . . . . . . . . 271
Subject table . . . . . . . . . . . . . . . . . . . . . . . . 271
Trigger activation time . . . . . . . . . . . . . . . . . . . . . 271
Triggering event . . . . . . . . . . . . . . . . . . . . . . . 271
Granularity . . . . . . . . . . . . . . . . . . . . . . . . . 272
Transition variables . . . . . . . . . . . . . . . . . . . . . . 273
Transition tables . . . . . . . . . . . . . . . . . . . . . . . 274
Triggered action . . . . . . . . . . . . . . . . . . . . . . . 275
Invoking stored procedures and user-defined functions from triggers . . . . . 277
Passing transition tables to user-defined functions and stored procedures 278
Trigger cascading . . . . . . . . . . . . . . . . . . . . . . . 278
Ordering of multiple triggers . . . . . . . . . . . . . . . . . . . . 279
Interactions between triggers and referential constraints . . . . . . . . . 280
Interactions between triggers and tables that have multilevel security with
row-level granularity . . . . . . . . . . . . . . . . . . . . . . 281
Creating triggers to obtain consistent results . . . . . . . . . . . . . 282
Part 3. Using DB2 object-relational extensions . . . . . . . . . . . . . . . . 285
Chapter 13. Introduction to DB2 object-relational extensions . . . . . . 287
Chapter 14. Programming for large objects . . . . . . . . . . . . . 289
Introduction to LOBs . . . . . . . . . . . . . . . . . . . . . . 289
Declaring LOB host variables and LOB locators . . . . . . . . . . . . 292
LOB materialization . . . . . . . . . . . . . . . . . . . . . . . 296
Using LOB locators to save storage . . . . . . . . . . . . . . . . . 297
Deferring evaluation of a LOB expression to improve performance . . . . 297
Indicator variables and LOB locators . . . . . . . . . . . . . . . 299
Valid assignments for LOB locators . . . . . . . . . . . . . . . . 300
Avoiding character conversion for LOB locators . . . . . . . . . . . 300
Chapter 15. Creating and using user-defined functions . . . . . . . . 301
Overview of user-defined function definition, implementation, and invocation 301
Example of creating and using a user-defined scalar function . . . . . . 302
User-defined function samples shipped with DB2 . . . . . . . . . . . 303
Contents vii