Foreign key problem

[lateesh poluparthi]

Hi All,
I have a table "MASTER" with primary key "acno".
and another table "TendTrans" with primary key "acno,TDate".

i am writing below query as

Alter table TendTrans add constraint foreign key (acno) references master(acno) on delete cascade;


it working perfectly.

but, whenever my server is restarted this foreign key constraint is failing and not showing.
again i have to write this alter command..

can any one pls tell me the remedy.......


thanks in advance.