Question

Here is my situation:

Situation:

I have users, and I have multiple values in multiple categories for each user.

The way I see it I have two options:

I. Make a new table ‘values’:

 user_ID   category   value 

  ...        ...       ...
   5          1        aaa
   5          1        bbb
   5          2        ccc
   5          2        ddd
   5          2        eee
   6          1        xxx
   6          2        yyy
   6          1        zzz

II. In my actual table with the users – ‘users’:

user_ID (unique)         values  
        5             aaa,bbb$$ccc,ddd,eee
        6             xxx,zzz$$yyy

…where I save the values as text and parse it with ‘,’ dividing values and ‘$$’ dividing categories.

So far I have been doing some little things the second way, but now I expect a lot of values and categories for this database and I am wondering which will give me less server load — having a very huge mySQL database table and go through it on every page to see which values belong to the current user ; or getting all and only his values from a relatively small table but parse the string every time with PHP to make it usable?

Answer 1

The first method – that is what a relational database is built for. You also have the added benefit of indexes, which will keep it speedy up even with a fairly large dataset.

Also, it allows the data to be queried from the other direction – fetch me all users with category 2 equal to ‘eee’