Case
SQLForeignKeyAction.noAction
The
NO ACTION behavior.case noAction
Discussion
NO ACTION triggers an SQL error indicating that the operation in progress has violated a foreign key constraint. For immediate constraints (the default in most systems), the behavior is identical to SQLForeignKeyAction.restrict. If the violated constraint is deferred, the error is not raised immediately, and the remainder of the query in progress is given an opportunity to complete and potentially negate the violation.
This is the default action.