[jira] [Commented] (DERBY-532) Support deferrable constraints

["ASF subversion and git services (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/DERBY-532?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13861164#comment-13861164 ] 

ASF subversion and git services commented on DERBY-532:
-------------------------------------------------------

Commit 1555006 from [~dagw] in branch 'code/trunk'
[ https://svn.apache.org/r1555006 ]

DERBY-532 Support deferrable constraints

Patch derby-532-allow-pk-unique-1, which opens up for using deferrable
constraints for primary key and unique constraints, i.e. it is no
longer required that the special property "derby.constraintsTesting"
be used for those constraints, since the implementation is complete
modulo bugs. Upgrade tests still remain to be built, though.

For foreign key and check constraints as well as for "not enforced",
the property will still required till the implementation for those is
completed.

> Support deferrable constraints
> ------------------------------
>
>                 Key: DERBY-532
>                 URL: https://issues.apache.org/jira/browse/DERBY-532
>             Project: Derby
>          Issue Type: Improvement
>          Components: SQL
>            Reporter: Jörg von Frantzius
>            Assignee: Dag H. Wanvik
>              Labels: derby_triage10_11
>         Attachments: IndexDescriptor.html, IndexDescriptorImpl.html, IndexRowGenerator.html, SortObserver.html, deferredConstraints.html, deferredConstraints.html, deferredConstraints.html, deferredConstraints.html, deferredConstraints.html, derby-532-allow-pk-unique-1.diff, derby-532-allow-pk-unique-1.status, derby-532-fix-drop-not-nullable.diff, derby-532-fix-drop-not-nullable.status, derby-532-fix-metadata-1.diff, derby-532-fix-metadata-1.status, derby-532-import-1.diff, derby-532-import-1.status, derby-532-import-2.diff, derby-532-import-3.diff, derby-532-import-3.status, derby-532-more-tests-1.diff, derby-532-more-tests-1.stat, derby-532-nullableUniqueFix.diff, derby-532-nullableUniqueFix.status, derby-532-post-scan-1.diff, derby-532-post-scan-1.stat, derby-532-post-scan-2.diff, derby-532-post-scan-2.stat, derby-532-post-scan-3.diff, derby-532-post-scan-3.stat, derby-532-post-scan-4.diff, derby-532-post-scan-4.stat, derby-532-serializable-scan-1.diff, derby-532-serializable-scan-2.diff, derby-532-serializable-scan-2.stat, derby-532-syntax-binding-dict-1.diff, derby-532-syntax-binding-dict-1.status, derby-532-syntax-binding-dict-2.diff, derby-532-syntax-binding-dict-2.status, derby-532-syntax-binding-dict-all-1.diff, derby-532-test-speedup.diff, derby-532-test-speedup.status, derby-532-test-with-default-deferrable-all-over.diff, derby-532-testAlterConstraintInvalidation.diff, derby-532-testAlterConstraintInvalidation.status, derby-532-unique-pk-1.diff, derby-532-unique-pk-1.status, derby-532-unique-pk-2.diff, derby-532-unique-pk-3.diff, derby-532-unique-pk-3.status, derby-532-xa-1.diff, derby-532-xa-2.diff, derby-532-xa-3.diff, derby-532-xa-3.status
>
>
> In many situations it is desirable to have constraints checking taking place only at transaction commit time, and not before. If e.g. there is a chain of foreign key constraints between tables, insert statements have to be ordered to avoid constraint violations. If foreign key references are circular, the DML has to be split into insert statements and subsequent update statements by the user.
> In other words, with deferred constraints checking, life is much easier for the user. Also it can create problems with softwares such as object-relational mapping tools that are not prepared for statement ordering and thus depend on deferred constraints checking.



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