title: Insert parentId automatically to child table in MySQL
body: <p>I have 2 tables, one is parent and another one is child. Parent table has a field called "parent_id" (primary key) and child table has a field called "parent_id"(foreign key) so there are link together. 
  If I insert a row into the parent table and at same time I also want to insert a row into child table with the same parent id in the parent_id field. How to do this?</p>