so im having problems with adding another primary key to my table. i have 3 columns: 1. Account ID (Identity) 2. EmailID 3. Data field

when i made the table i had this to make the Account ID and the Email ID unique

PRIMARY KEY (AccountID, EmailID)

i thought that would make my emailid unique, but then after i tried inserting another row with the same emailid it went through. so i thought i missed something out.

now for my question:

1. IF, i had to use alter, How do i alter the table/PK Constraint to modify the EmailID field and make it Unique
2. IF i decided to drop the table and made a new one, how do i make those two primary keys uniqe?

Thanks a bunch!!