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'Java')}. Several of the major database vendors do not support this function style in a pathetic
effort to lock users into their database. The mapping for these functions can be overridden by
adding function-mapping elements to the type-mapping element. The following is an example of
the concat function mapping for Oracle 9i.
Oracle9i
concat
(?1 || ?2)
Listing C-2, The jbosscmp-jdbc.xml Function Mapping Declaration
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Appendix
D
D. Revision History
This appendix lists changes to this document and changes to JBossCMP.
Beta 1
Chapter 2 Entities
Changed type-mapping element in entity and defaults to datasource-mapping. This change was
required to enable DTD validation.
Moved description of read-ahead to Chapter 6
Removed the debug element. Logging is now completely controlled by log4j.
Clarified interpretation of read-time-out element.
Changed select-for-update element to row-locking. Not all database vendors support the
SELECT FOR UPDATE syntax, but most support some form of row locking.
Chapter 3 CMP-Fields
Moved description and specification of eager/lazy loading to Chapter 6.
Support for not-null columns has been added.
Chapter 4 Container Managed Relationships
Completely changed the mapping of relationships in ejb-jar.xml.
Moved the ejb-relationship-role elements out of the foreign-key-mapping and
relation-table-mapping elements.
Merged foreign-key-fields and table-key-fields into a common key-fields element. Keys
are now always defined in terms of the current entity. This changes nothing for relation-
table-mapped relationships, but for foreign-key-mapped relationships, the key-field
mapping is exactly backwards.
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A P P E ND I X D : R E V I S I O N HI S T O R Y P A G E 6 8
Added support for read-only relationships with the introduction of the read-only and read-time-
out elements.
Added support for automatic foreign-key constraint generation with the addition of the
fk-constraint element to ejb-relationship-role.
Added support for all table related configuration elements to relation-table-mapping.
Chapter 6 Optimized Loading
The read-ahead code has been completely rewritten.
The specification of eager/lazy loading groups has completely changed.
Added named load groups which are referenced in the eager-load-group, lazy-load-groups,
and read-ahead elements.
The eager-load element has been replaced with the eager-load-group element, which only
contains the name of the group to eager load by default.
The lazy-load-groups element no longer contains lazy-load-group elements; rather it
contains load-group-name elements.
A row-locking-template has been added to type-mapping elements to enable vendor specific
row-locking syntax.
Beta 2
Chapter 5 Queries
Completely rewrote EJB-QL compiler using JavaCC.
Removed restriction on mySQL usage of NOT EMPTY operator by adding support for
LEFT JOIN instead of EXISTS subquery.
Fixed the mapping of MEMBER OF and NOT EMPTY clause.
Added JBoss query language (JBossQL).
Added DynamicQL, which allows runtime compilation and execution of JBossQL.
Changed DeclaredSQL to allow finder to use DISTINCT.
Added the ability to specify the alias used for the main select table.
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