Hibernate and Inheritance Mapping

May 27, 2008 by Michael

Hibernate supports multiple types of inheritance mapping, some of them (Table per class, Table per subclass) using a discriminator column to decide the class.

The type of the discriminator can be one of

string, character, integer, byte, short, boolean, yes_no, true_false

In case you need to use any other than string or character, i.e. integer, you have to give the base class a default discriminator-value like 0 or -1 or whatever fits, otherwise you’ll end up with a an exception like:

org.hibernate.MappingException: Could not format discriminator value to SQL string

as Hibernate uses the class name of the base class to derive a default value.

No comments yet

Post a Comment

Your email is never published nor shared. Required fields are marked *