MYSQL RESTRICT CASCADE SET NULL

The main table, from the table "MYSQL"//http://my.oschina.net/cart/blog/277624 empty, RESTRICT, no action delete: From the table record does not exist, the main table can be deleted. Delete from table, Main table unchanged update: The primary table cannot be updated when the table record does not exist. Update from table, Main table unchanged//http://my.oschina.net/cart/blog/277624cascade Delete: Delete primary table automatically when deleted from table. Delete from table, Main table unchanged update: Automatically updates the table when the primary table is updated. Update from table, Main table unchanged//http://my.oschina.net/cart/blog/277624set NULL Delete: Automatically update from table value NULL when primary table is deleted. Delete from table, Main table unchanged update: Automatically update from table value to NULL when updating Main table. Update from table, Main table unchanged

　　

MYSQL RESTRICT CASCADE SET NULL