Deletion on multiple tables

[Prarthana Choudhary]

Hi,
this is my first post,I am fresher in Database and development.
My problem is that....
I am having four tables related to Order placed, two more tables are there T1 and T2
So, T1 and T2 is having primary keys which are used in some of the Order related tables.Now for some records we may have more than two records with respect to one record of table T1.

This time i am using an SP ,where first of all, I drop all fk constraints from T1 and T2,then delete records and then add contarints again
but problem comes when for one record in T1 i am having more than 2 records in Order tables, as records from T1 is alredy deleted, So can't be added again.
I just want to know how to check for constarint name it is already exiting or not.

[Prarthana Choudhary]

Thanks,
i got solution