MySQL的：删除行，其中列= ID后删除ID

Question

I have 1 table like this

ID   parent
1    null
2    1
3    1

now when I delete ID 1 I need auto delete all rows which parent = 1 . I try trigger a/b delete but give error for recursive trigger.

thanks

Answer 1

You might want to look into FOREIGN KEY constraints and CASCADE rather than using triggers. https://dev.mysql.com/doc/refman/5.7/en/create-table-foreign-keys.html

Answer 2

Yes you cant use trigger for the same table which may result in dead lock so here you cant use trigger.
You should use foreign key. Here is an example

ALTER TABLE `employee` ADD INDEX ( `parent_id` );


ALTER TABLE `employee` ADD CONSTRAINT `employee_ibfk_1` FOREIGN KEY ( `parent_id` ) REFERENCES `test`.`employee` (
`id`
) ON DELETE CASCADE ON UPDATE CASCADE ;

Here when you delete the parent data all the child rows will be deleted.