JPA: Why GenerationType.AUTO could not be used with InheritanceType.TABLE_PER_CLASS strategy

Question

Could somebody explain why InheritanceType.TABLE_PER_CLASS could not use the GenerationType.AUTO strategy for primary key value generation when mapping inheritance?

Longdistance

GenerationType.AUTO is used when the db table has its own auto generation of ids e.g. AUTO_INCREMENT . This may not work in the the TABLE_PER_CLASS scenario as you would have collisions between each of the independently generated ids and so could not guarantee a unique id for any entity instance within the hierarchy – Renita