Question

I have a table rating with these fields rate_id, game_id, rating, ip. Let suppose that these fields has the following values 1,130,5,155.77.66.55

When a user try to vote for a game, I want with mysql to check if he has already vote for this game so mysql will check if ip and game_id already exists, if they exists then mysql will update the value of rating otherwise will create a new entry.

What is a efficient way to do this?

Answer 1

Create unique index that covers ip + game_id. After that you can use INSERT … ON DUPLICATE KEY UPDATE statement.

So the total query will be something like

INSERT INTO rating (rate_id, game_id, rating, ip) VALUES (1,130,5,'155.77.66.55')
ON DUPLICATE KEY UPDATE rating = 5