Determine which posts the user has already rated

Hi,

I see that in the Manage Ratings section you have a list of all ratings for all posts and who rated each one.

I would like a way to determine if a user has rated a particular post (if so, I don’t want him or her to see the post again). Is that possible? I know the information is there, but I don’t know how I can retrieve and use it?

Many thanks!