how to optimize query

Is there any single query to delete the child tables if the parent table will be deleted?

tables:

t1

t1_id 1

t2

t2_id t1_id 1 1 2 1

t3

t3_id t2_id 1 1 2 1 3 1

t4

t4_id t3_id 1 开发者_StackOverflow社区 1 2 1

So if I will delete t1_id =1 , all children rows must also be deleted to avoid orphan data... In this case all data in these 4 tables should be deleted.. Is there any single line of query how to this?

Thank you so much.

You should have a look at using

FOREIGN KEY Constraints

with ON DELETE CASCADE

CASCADE: Delete or update the row from the parent table and automatically delete or update the matching rows in the child table.

Your best bet is to define foreign keys and declare the tables to cascade on delete. Have a look to the SQL syntax.