Friday, December 2, 2016

What is MappedSuperClass in hibernate ?

MapperSuperClass


·        A mapped superclass has no separate table defined for it.
·        Designates a class whose mapping information is applied to the entities that inherit from it. 
·        A class designated with the MappedSuperclass annotation can be mapped in the same way as an entity except that the mappings will apply only to its subclasses since no table exists for the mapped superclass itself. 
·        When applied to the subclasses the inherited mappings will apply in the context of the subclass tables. 
·        Mapping information may be overridden in such subclasses by using the AttributeOverride and AssociationOverride annotations or corresponding XML elements.
·        It avoids the code repetition like adding an id, version or timestamp fields in every Hibernate entity.

Example:

AbstractEntity.java class having MappedSuperClass but no Entity annotation.





User Class extends AbstractEntity class and will persisting user object, it will also persist Id and other details of mapped Class.



You can download the whole source code for Github.

After running the query, Attributes of AbstractEntity class will get created under 'USER' table.


Happy Coding...!!!