I have 2 tables: users and items. Each item has a user#. So, if I want to find only items associated with a particular user I can: 

> 
> SELECT \* FROM items WHERE user\_id = "$user\_id";
> 
> 
> 

But if there are thousands of items, searching through the table will take forever, right?

Is there a better way to go about doing this? Maybe a way to store all item numbers associated with a user into a field in the users table?

Thanks,
Jason