A way to check if foreign key exists in SQL 2005

Question

Is there an easy way to check if a foreign key exists for a column in a table? I am writing a script which will add the foreign key only if it does not exist.

Answer 1

Woo-hoo! I just spent the past two days doing this.

IF NOT EXISTS ( SELECT  name
                FROM    sys.foreign_keys
                WHERE   name = 'FK_Name' ) 
    ALTER TABLE table_name ADD CONSTRAINT FK_Name FOREIGN KEY (idcol) 
                           REFERENCES OtherTable(idcol)