Djelorean

I'm working on a chat program with several channels that the user can be in at once. I've gotten it to work fine with hard-coded arrays for now, but I need to be able to save what channels the user is in to the database (mySQL). Additionally, one of the channels will be flagged as the one they are actually in. In the code now, I'm just using an array of the channel numbers, with the first element as the flagged channel. This can be easily modified if there is a way that would work with the database better. What I'm stuck on is how I should go about saving this list. I've figured out ways that can work, but are inefficient (serialize, a string to explode()). Any suggestions would be appreciated.