hi, good day, i have a question on primary key , currently, i have a table call "newcampaign" which already contain a primary key, named "cam_code", now let say i want to add another primary key"cam_name" to existing "newcampaign" table ,

so i using
but it give me error , say multiple primary key defined

so i need to drop all primary key before add both of primary key (cam_name,cam_code)?


another question is , if the table consist of 3 primary key, now i want to drop only one of the primary key , what should i do ? thank you very much !!

you can only have one primary key per table, as far as I'm aware. However you can create other keys which have unique values.

If you want to set another key as primary key then youwillneed todelete the old index first, and the add the new index

You may find it easier to do this through soemthing like MySQL admin, dbtools or PHPAdmin
HTH