Inheritance - rafalkieras/jpa-kss GitHub Wiki

#Inheritance

##Mapped superclass

@MappedSuperclass - designates a class whose mapping information is applied to the entities that inherit from it. A mapped superclass has no separate table defined for it.

##Single table

InheritanceType.SINGLE_TABLE - there is only one table and it contains all the fields of the all classes in the hierarchy. This is the default strategy.

This table has a discriminator column containing a value that identifies the subclass to which the instance represented by the row belongs.

##Joined

InheritanceType.JOINED - there is a table for each class, tables for subclasses contain only those fields that are specific to those classes.

##Table per class

InheritanceType.TABLE_PER_CLASS - there is a table for each concrete class (non-abstract) class and each table contains all the fields (for the superclasses as well). Support for this strategy is optional and may not be supported by all Java Persistence API providers.