Your last statement indicates that you are getting the right idea.

Typically, this third table is used to crate many-to-many relationships, and you usually want to add more "relationship" data into this table, such as the date when the relationship was established, and perhaps WHO did it.

In your case, it seems like a particular car can have only ONE size (one-to-one from the car's perspective) , so it makes sense to add the sizeid into the cars table (as a foreign key).

Now, if you introduce a MANUFACTURERS table with "Toyota", "Honda", "Ford" etc, you will need to add a manuf-id into the cars table (another one-to-one from the cars point of view). Now you can do a somewhat more complex query, to determine what sizes a particular manufacturer makes.

Have fun !

        "I can cast out either one of your demons, but not both of them." -- the XORcist

In reply to Re^3: inserting a column into mySQL DB with perl by NetWallah
in thread inserting a column into mySQL DB with perl by diyaz

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