Originally posted by Shobana Sukumar:
i need to work with a table which has two primary keys.
To be precise, that's impossible. A table can have only one primary key, that's the basic fundamental meaning of "primary". You can however, have a primary key composed of more than one column. A primary key is nothing more or less than a unique index with a very special (primary) relationship to the table; most databases implement it that way.
The previous response appears to be on the right track for "how do I work with a table which has a primary key with multiple columns?".