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From "ASF subversion and git services (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (DERBY-532) Support deferrable constraints
Date Fri, 30 Aug 2013 18:24:52 GMT

    [ https://issues.apache.org/jira/browse/DERBY-532?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13754978#comment-13754978
] 

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

Commit 1519045 from [~dagw] in branch 'code/trunk'
[ https://svn.apache.org/r1519045 ]

DERBY-532: Support deferrable constraints

Patch derby-532-testAlterConstraintInvalidation.

Adds a fixture to test that prepared statement is invalidated when a
table its depends on undergoes an ALTER TABLE ALTER CONSTRAINT
statement. As it turns out, this is already handled by the common
machinery for ALTER TABLE.
                
> 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: deferredConstraints.html, deferredConstraints.html, 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-testAlterConstraintInvalidation.diff,
derby-532-testAlterConstraintInvalidation.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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