[Hibernate-issues] [Hibernate-JIRA] Commented: (HB-478) Foreign Key constraints duplicated with SchemaUpdate

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The following comment has been added to this issue:

     Author: Gerjon de Vries
    Created: Wed, 19 Nov 2003 3:05 AM
       Body:
The problem will only reproduce with mysql-connector-java-3.0.9-stable-bin (I wrote 3.0.8 in the original message by mistake).
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View the issue:

  http://opensource.atlassian.com/projects/hibernate/secure/ViewIssue.jspa?key=HB-478


Here is an overview of the issue:
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        Key: HB-478
    Summary: Foreign Key constraints duplicated with SchemaUpdate
       Type: Bug

     Status: Unassigned
   Priority: Major

    Project: Hibernate2
   Versions:
             2.0.3

   Assignee: 
   Reporter: Gerjon de Vries

    Created: Tue, 18 Nov 2003 10:48 AM
    Updated: Tue, 18 Nov 2003 10:48 AM
Environment: MySql 4.0.16-Max, mysql-connector-java-3.0.9-stable-bin, InnoDB tables, Linux (SuSe 9.0).

Description:
When using SchemaUpdate to create/alter table definitions, each consecutive use of "SchemaUpdate(configuration).execute(true)" will regenerate all foreign key constraint commands (e.g. "ALTER TABLE X add index(fromId), add constraint FK2065BD77CB5B07 foreign key (fromId) references Y(id)"). Effectively you get duplicates for each key, which might degrade performance, and after some time cause errors, since MySql allows a limited number of FK's.

It seems to me that this is caused by a mismatch of the constraint names in net.sf.hibernate.mapping.Table and net.sf.tool.hbm2ddl.TableMetaData, but I'm not 100% sure. The "ALTER TABLE ..." is generated in Configuration.java:462.

Note that I'm using InnoDB tables (for the transaction support). Also note that the problem will only reproduce with mysql-connector-java-3.0.8-stable-bin (or newer), since older versions have a bug with requesting foreign key information on InnoDB tables.



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