mysql - Cascade Not Working -

i have couple tables weakly connected , delete work across both of them when delete main table.

table 1:

create table car( cid integer, color varchar(10), primary key (cid) );  create table tags( tid integer, expdate varchar(10), cid integer, primary key (tid, cid), foreign key (cid) references car(cid) on delete cascade ); 

but when delete car car table, not deleted tags table. i've tried adding constraint after table creation same result.

set sql_mode="no_auto_value_on_zero"; set time_zone = "+00:00";   -- --------------------------------------------------------  -- -- table structure table `car` --  create table if not exists `car` (   `cid` int(11) not null auto_increment,   `color` varchar(10) default null,   primary key (`cid`) ) engine=innodb  default charset=latin1 auto_increment=5 ;  -- -- dumping data table `car` --  insert `car` (`cid`, `color`) values (2, 'b'), (4, 'a');  -- --------------------------------------------------------  -- -- table structure table `tags` --  create table if not exists `tags` (   `tid` int(11) not null auto_increment,   `expdate` varchar(10) default null,   `cid` int(11) not null default '0',   primary key (`tid`,`cid`),   key `cid` (`cid`) ) engine=innodb  default charset=latin1 auto_increment=7 ;  -- -- dumping data table `tags` --  insert `tags` (`tid`, `expdate`, `cid`) values (3, 'aa', 2), (4, 'bb', 2), (5, '11', 4), (6, '22', 4);  -- -- constraints dumped tables --  -- -- constraints table `tags` -- alter table `tags`   add constraint `tags_ibfk_1` foreign key (`cid`) references `car` (`cid`) on delete cascade; 

--now delete record ;

--delete car cid=4;