how delete parent row with all child row from other table
<pre>parent_table
----------------------------------------------------------------------
id         name
1           a
2           b

child_table
---------------------------------------------------------------------
id        parent_table_id            name
1               1                      c
2               1                      d
3               1                      e
4               2                      f
5               2                      g
</pre>

<p>When I will delete first row from parent table then all child row of parent first row.
how is it possible??</p>