[RESOLVED] Help: To see if a user voted or not

[spetstnelis]

Hi, first time poster, and I'm not entirely experienced...

Here is the situation: I am in process of creating a website where users can vote items, much like Digg. I am using MySQL and PHP. In my mysql database, I have two tables, one of them for users and the other for the items which users can vote on.

In order to vote, a user clicks on a link, with the href="voteup.php?id=3" where 3 could be any number - it's the id of the item they are voting on. This vote adds one to the row of the item.

The problem: I don't know how to keep track of what items each user voted on. And since I can't keep track, I cannot prevent them from voting infinitely on each item. Does anyone have any ideas on what I could do to keep track of what items the user votes?

I was considering adding an additional column on the table for the items, with a string of USER IDs, but I'm not entirely sure where to go with that.

Thanks in advance!

[laserlight]

So, you have a table of users and a table of items. Clearly, there is a many to many relationship between users and items: a user can vote on multiple items, and each item can be voted on by multiple users. This suggests that you should have a third table, say votes, that has at least two columns: the id of the user that voted, and the id of the item that was voted on. If you make the combination of these two columns unique (and you should) then it becomes impossible for a user to vote on the same item more than once (assuming that your database system enforces unique constraints).

[spetstnelis]

Wow, and here I spent hours thinking of a solution with only two tables. Thank you very much!