delete a data from 3 tables

hi all
*
I created 3 tables namely*authen_tbl,profile_tbl,astro_tbl,in which column name*mail *as primary key in authen_tbl table*,
query:
*pid int primary key auto_increment,
*foreign key (mail) references authen_tbl(mail)
given in astro_tbl table
and
query
foreign key(pid) references profile_tbl(pid)
given in astro_tbl.
*
My problem is how to delete a data at a strech from 3 tables.
*
Thanks
chandra