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https://issues.apache.org/jira/browse/DERBY-532?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13834914#comment-13834914
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Dag H. Wanvik edited comment on DERBY-532 at 11/28/13 3:18 PM:
---------------------------------------------------------------
Here is one fallout of running the regressions with default constraint mode
deferrable.
Uploading a patch ("derby-532-fix-metadata-1") that fixes broken database
metadata for deferred constraint indexes: the metadata query used the method
IndexDescriptor#isUnique to determine logical uniqueness, but it really
represents physical uniqueness now. For deferred unique constraints, the method
that should be used is "isUniqueDeferrable". Added a test, and also added
client/server run of the regression test for deferred constraints.
Before the fix, the added test fixture "testDatabaseMetaData" failed in that
the index in question was identified as non unique, but it is logically unique.
When changing the code for the database metadata query, I discovered DERBY-6423.
was (Author: dagw):
Here is one fallout of running the regressions with default constraint mode
deferrable.
Uploading a patch that fixes broken database metadata for deferred constraint
indexes: the metadata query used the method IndexDescriptor#isUnique to
determine logical uniqueness, but it really represents physical uniqueness now.
For deferred unique constraints, the method that should be used is
"isUniqueDeferrable". Added a test, and also added client/server run of the
regression test for deferred constraints.
Before the fix, the added test fixture "testDatabaseMetaData" failed in that
the index in question was identified as non unique, but it is logically unique.
> 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-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-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-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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