Difference between revisions of "EclipseLink/Development/JPA/QueryDownCast"

Latest revision as of 05:56, 9 February 2010

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-= Enhancement: Query Down Cast =
+#REDIRECT [[EclipseLink/Development/2.1/AdvancedJPA_Queries/DownCast]]
-This page captures the requirements, design, and existing functionality for {{bug|?}} to enable EclipseLink JPA/ORM developers to define queries on inheritance hierarchies with down casting to specific classes.
-== Requirements ==
-== Work-Arounds ==
-Since this feature will take significant development effort the following suggest work-around options are provided to assist users who require this functionality. If having this is a show-stopper for your project please vote for and add your feedback to {{bug|?}}.
-=== Single Class Results ===
-While this may seem obvious it often important to point out all potential solutions. If the query you are executing will only be returning a single type from the inheritance hierarchy then it is important that that be the target type of the query. This will allow you to access all mapped attributes in this class and its mapped parent classes.
-=== Accessing un-mapped attributes using QueryKey for SINGLE_TABLE ===
-When your inheritance hierarchy leverages a common table for multiple mapped classes in the hierarchy it is possible to query for attributes that are not visible in the class you are querying for through the use of query keys.
-== Solution Design ==
-TBD