Hello,
How do I get Hibernate to delete a many-to-many relation automatically when I have it delete one of the related items?
For example:
I have two entities (domain objects), let's say Employee and Project. One or more employees can be involved in one or more projects.
The domain objects are mapped to the tables EMPLOYEE and PROJECT respectively. A third table, EMPLOYEE_PROJECT, functions as the coupling between the two, holding only a EMPLOYEE_ID (with a constraint to EMPLOYEE.ID) and a PROJECT_ID (with a constraint to PROJECT.ID).
Imagine I delete a Project using session.delete(myProject).
Hibernate complains it can not delete the project, because of the constraint with EMPLOYEE_PROJECT.PROJECT_ID.
I want it to delete that coupling as well, without deleting any Employees of course!
The many-to-many relationship is defined in the mapping file of Employee.
On the internet I found a suggestion to not define a many-to-many in Employee, but to have both Project and Employee refer one-to-many to the coupling table. See:
http://forum.hibernate.org/viewtopic.php?p=2319035&sid=b0f26afec36fb875f485784b8ea2c5d6 Would this really be necessary to solve the problem?
Maybe I could move the many-to-many definition to the Project mapping file instead, but then I would have the same problem when deleting an Employee.
Am I overseeing something? Help is much appreciated! Thanks!
[ August 24, 2006: Message edited by: Kjeld Sigtermans ]