django on-delete options

The Django framework provides several options for handling the on-delete behavior of related objects when a referenced object is deleted. These options are:

1. CASCADE: When the referenced object is deleted, all related objects are also deleted. This is the default behavior if no on-delete option is specified.

2. PROTECT: Prevents the deletion of the referenced object if any related objects exist. An exception is raised if an attempt is made to delete the referenced object.

3. SET_NULL: Sets the foreign key to NULL for all related objects when the referenced object is deleted. This requires the foreign key to allow NULL values.

4. SET_DEFAULT: Sets the foreign key to its default value for all related objects when the referenced object is deleted. This requires the foreign key to have a default value specified.

5. SET(): Sets the foreign key to the value passed as an argument for all related objects when the referenced object is deleted. This allows for customization of the behavior based on specific requirements.

6. DO_NOTHING: Leaves the foreign key unchanged for all related objects when the referenced object is deleted. This can lead to referential integrity issues if not handled properly.

These on-delete options can be specified using the on_delete parameter in Django's ForeignKey or OneToOneField definitions. Each option provides a different way to handle the deletion of related objects and allows for flexibility in managing relationships between objects in the database.