Hibernate won't remove parent but removes children (or relationship) when it fails to delete parent because of foreign key constraint

Question

I have some entities (WarehouseTransactionGroup, WarehouseTransactionAttribute, AttributeValue) with following relationship:

@Entity
public class WarehouseTransactionGroup extends MasterEntity {

   @ManyToMany(cascade = CascadeType.ALL)
   @MapKeyColumn
   private Map<WarehouseTransactionAttribute, AttributeValue> attributes;

   // Getter and setter

}

When I try to remove a object of type WarehouseTransactionGroup, it naturally fails due to foreign key constraint since the object is used in some other database record. However, Hibernate clears the data in attributes field.

I am calling remove operation, ie, session.delete() inside a transaction.

Why is this happening and how can I fix it?

Answer 1

You shouldn't use CascadeType.ALL for @ManyToMany associations.

1. You need to change the cascade to CascadeType.PERSIST, CascadeType.MERGE :

   @ManyToMany(cascade = {CascadeType.PERSIST, CascadeType.MERGE}) @MapKeyColumn private Map attributes;

2. The delete goes like this:

    WarehouseTransactionGroup wtg = ...; attributes.clear(); em.remove(wtg);