Chapter 8 Creating J2EE Applications for BEA WebLogic

Configuring persistence properties for a Component

• Automatic Key Generation - WebLogic Server supports an automatic primary key generation feature for container-managed-persistence (CMP). By default, PowerAMC uses DBMS primary key generation when columns mapped to attributes are auto-incremented, but it lets you override this by updating the following extended attributes:
  
  
  • generator-type (Component extended attribute)
  • generator-name (Component extended attribute)
  • key-cache-size (Component extended attribute)
• For more information on WebLogic automatic key generation, see Automatic Primary Key Generation.
• Delay Database Insert Until - The delay-database-insert-until extended attribute specifies the precise time when a new bean that uses RDBMS CMP is inserted into the database.
  
  It is advisable to delay the database insert until after the ejbPostCreate method modifies the persistent fields of the bean. This can yield better performance by avoiding an unnecessary store operation.
  
  For maximum flexibility, you should avoid creating related beans in your ejbPostCreate method. This may cause the delay database insert impossible if database constraints prevent related beans from referring to a bean that has not yet been created.
  
  
  • delay-database-insert-until (Component extended attribute)
• For more information, see Delay-Database-Insert-Until.

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