multiple tables lookup

[Anon]

on a website i'm working on there is a database with 2 tables. One table is called mods the other mods_how_to. When a user fills out the form to submit a mod the information from the form is added to the table called mods, using auto increment for a reference number. If the field in the form for how to is filled out that information is added to another table called mods_how_to using the same reference number as the entry in the the mods table that it corresponds to.

on another page there's an html table that takes the information from the databse and displays it. What i want to know is if it is possible, (and how i would go about doing it assuming it is) to have it check if the second table to see if that mod has a how to and if so spit out a link that would take you to a page with that how to.. I hope that makes some sense..

Thanks in advance for any help

[matto]

yes, that's an easy task.

but I suggest you improve your database design. is there really max. one howto for each mod? if so, you can put it into the same table as the mod, just add a field for it.

if this is an 1:n relation, use a foreign key for pointing from the howto to the mod table. i.e., give the howtos an own primary key (auto-increment key) and add a column "id_mod" which contains the corresponding mod's id. this is called a "foreign key".

for example:

table mods:
id, text

table howtos:
id, id_mod, text

you could read some articles on database modelling in phpbuilder's articles section, too.

hth!

[sapphire]

well the thing is that not every mod includes a how to.. in fact most of them don't, and i read that in mysql databases it is not a good idea to have lots of blank fields.

I'm new to all of this so maybe what i read was incorrect.