Hibernate Cascade Options – Cascade Attribute In Hibernate

Cascade Attribute In Hibernate

Main concept of hibernate relations is to getting the relation between parent and child class objects

Cascade attribute is mandatory, when ever we apply relationship between objects, cascade attribute transfers operations done on one object onto its related child objects

If we write cascade = “all” then changes at parent class object will be effected to child class object too,  if we write cascade = “all” then all operations like insert, delete, update at parent object will be effected to child object also

Example: if we apply insert(or update or delete) operation on parent class object, then child class objects will also be stored into the database.

default value of cascade =”none” means no operations will be transfers to the child class

Example: if we apply insert(or update or delete) operation on parent class object, then child class objects will not be effected, if cascade = “none”

Cascade having the values…….

• none (default)
• save
• update
• save-update
• delete
• all
• all-delete-orphan

In hibernate relations, if we load one parent object from the database then child objects related to that parent object will be loaded into one collection right (see one-to-many insert example).

Now if we delete one child object from that collection, then the relationship between the parent object and that child object will be removed, but the record (object) in the database will remains at it is, so if we load the same parent object again then this deleted child will not be loaded [ but it will be available on the database ]

so finally what am saying is all-delete-orphan means, breaking relation between objects not deleting the objects from the database, hope you got what am saying ?

Note:
what is orphan record ..?
an orphan record means it is a record in child table but it doesn’t have association with its parent in the application.

[ And ]

In an application, if a child record is removed from the collection and if we want to remove that child record immediately from the database, then we need to set the cascade =”all-delete-orphan”

And that’s it about this cascade attribute in hibernate, hope i explained all the values..!!