You are correct in what you say
First make a table for the catagories ie
cat_id c_name
1 firscat
2 secondcat
then add a field to your reviews database ie
id reviews cat
1 whatever 1
2 whatever2 2
and so on.
Then all you will have to do is call the quirie ie
$result = mysql_quirie("Select * from table reviews where cat ='1'");
then your while loop etc etc
