[jira] [Comment Edited] (DERBY-532) Support deferrable constraints

["Dag H. Wanvik (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/DERBY-532?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13983798#comment-13983798 ] 

Dag H. Wanvik edited comment on DERBY-532 at 5/9/14 8:15 PM:
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With the latest commit, deferrable constraints ought to (prove me wrong!) work for

- unique/primary key constraints
- referential constraints (aka foreign key constraints)
- check constraints

I do not intend to add support for column NOT NULL constraints. Also, there is no support yet for changing constraints to "not enforced", otherwise the standard semantics of SQL 2011 should apply. 

I intend to add a few more tests for foreign key constraints. [Update: Cf DERBY-6559].



was (Author: dagw):
With the latest commit, deferrable constraints ought to (prove me wrong!) work for

- unique/primary key constraints
- referential constraints (aka foreign key constraints)
- check constraints

I do not intend to add support for column NOT NULL constraints. Also, there is no support yet for changing constraints to "not enforced", otherwise the standard semantics of SQL 2011 should apply. 

I intend to add a few more tests for foreign key constraints.


> 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
>             Fix For: 10.11.0.0
>
>         Attachments: IndexDescriptor.html, IndexDescriptorImpl.html, IndexRowGenerator.html, SortObserver.html, deferredConstraints.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-check-constraints-1.diff, derby-532-check-constraints-1.stat, derby-532-check-constraints-2.diff, derby-532-check-constraints-2.stat, 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-fk-1.diff, derby-532-fk-3.diff, derby-532-fk-3.stat, derby-532-fk-4.diff, derby-532-fk-5.diff, derby-532-fk-5.stat, derby-532-fk-6.diff, derby-532-fk-6.stat, derby-532-fk-7.diff, derby-532-fk-7.stat, derby-532-fk-baseline-2.diff, derby-532-fk-baseline.diff, 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-metadata-queries.diff, derby-532-metadata-queries.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-upgrade-1.diff, derby-532-upgrade-1.status, derby-532-upgrade-1b.diff, 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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