Return RevisionEntity with maximal number which satisfied the following conditions:
RevisionEntity.resourceType=revisionEntity.resourceType. RevisionEntity.userId=revisionEntity.userId.
* Return RevisionEntity which satisfied the following conditions:
RevisionEntity.resourceId=revisionEntity.resourceId;
RevisionEntity.resourceType=revisionEntity.resourceType.
RevisionEntity.userId=revisionEntity.userId.
Represent root revision entity.
Retrieving Root revision is one of the most often operation, so it make sense to use table per subclass mapping
strategy for speed up performance.