How can I detect redundant rows in the table?

Question

I\'m following solution #1 of this answer. After a while, there will be some redundant rows in the table. Suppose this table:

+------+------         


        

Answer 1

Create code that checks for the user already existing in the cookie table.

If the user id exists in the user column - just update it with the new cookie information. If the user id doesn't exist, create a new record.

Or you can check for existing records, delete them, and then insert the new one.