Kodo 4.2 - JDO - Not Handling Bi-Direcitonal Relationships Efficiently.
Last updated on MAY 24, 2017
Applies to:Oracle Kodo - Version: 4.1
Oracle Weblogic Server - Version: 10.3.2 and later ]
Information in this document applies to any platform.
- Parent object has a one-to-many relationship to Child objects.
- Child has a field that is a reference back to the Parent (so a bi-directional relationship).
- The Child mapping of the field that references back to the Parent uses the default-fetch-group attribute
When setting a fetch plan programmatically that includes retrieving fields on Parent object (including the field that contains a collection of Child objects) plus Child's field that is a reference back to Parent, it was found that the SQL generated was very inefficient. First a query looks up the fields for the Parent. Next, there is a query for each Child element to look up its parent, even though the parents were looked up in the first query.
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