Question

Because I have so many categories, I created a single “categories” database table :

"id_category , parent_id , category_name , category_tag"

example :

  ----------------------------------------------------------
  | id_category | parent_id | category_name | category_tag |
  ----------------------------------------------------------
  | 1           | 0         | Cars          | cars         |
  | 2           | 1         | Parts         | parts        |
  | 3           | 2         | Accesories    | accesories   |
  ----------------------------------------------------------

the tree :

  Cars
     |_Parts
           |_Accesories

My problem occurs when I want to delete all records in the tree.
How do I delete all records in the tree branch from above example.

Is that possible in mySQL with PHP?

Answer 1

http://dev.mysql.com/doc/refman/5.5/en/innodb-foreign-key-constraints.html

What you’re looking for is a foreign key on parent_id that references id_category with constraint ON DELETE CASCADE. Then you can just delete the root element (category_id 0) and you should end up with an empty table.