db-derby-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Mike Matrigali (JIRA)" <j...@apache.org>
Subject [jira] [Comment Edited] (DERBY-532) Support deferrable constraints
Date Thu, 14 Nov 2013 00:51:26 GMT

    [ https://issues.apache.org/jira/browse/DERBY-532?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13822037#comment-13822037
] 

Mike Matrigali edited comment on DERBY-532 at 11/14/13 12:50 AM:
-----------------------------------------------------------------

it would be good either as part of this project or a follow on to enhance the consistency
checker to make sure keys in these indexes that support deferable constraints are all unique
within whatever the appropriate guidelines 
(ie. allow duplicate nulls or not).  If a table level lock is held then it should be true
that there are no duplicates, even though the underlying implementation btree is a duplicate
allowing index.

being able to run this after some set of stressing the deferable constraint code in tests
might make it easier to test.


was (Author: mikem):
it would be good either as part of this project or a follow on to enhance the consistency
checker to make sure keys in these indexes that support deferable constraints are all unique
within whatever the appropriate guidelines 
(ie. allow duplicate nulls or not).  If a table level lock is held then it should be true
that there are no duplicates, even though the underlying implementation btree is a duplicate
allowing index.

> 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, deferredConstraints.html,
deferredConstraints.html, 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-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-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.



--
This message was sent by Atlassian JIRA
(v6.1#6144)

Mime
View raw message