I'm wondering what is best practice in the following scenario....
I need to store 3 columns of data: a Member ID, another Member ID and a Date.
Each row of data is unique. i.e. there can only be one combination of Member ID's on a given date.
So, in a situation such as this, is it best to have an auto incremented primary key or make Member ID, the second Memner ID and the Date the primary key?
It may be worth noting that the table will be queried to return the details of each second member ID where the first member ID is equal to X.
It may also be worth nothing that multiple INSERTS for the same member combination on the same date may be attempted so the query would either have to use IGNORE or a WHERE depending upon the best way forward.