Question regarding keyword checkboxes in database design

Hello,

Apologies in advance, because this post might be long, but I'm not sure how
to explain what I need to for this question to make sense otherwise.

I'm a total PostgreSQL beginner, working in a contract job that initially
involved developing a database in FileMaker Pro and then evolved into
porting it to the web using PostgreSQL because FMP web hosting was too
expensive. So now I'm working on all kinds of thorny conversion issues. I've
more or less given up on getting the two to interact the way I'd initially
hoped, using a third-party SQL plug-in for FMP, because there are too many
differences in the way they store data. So it's probably going to end up
being only in Pg, and with people who update it after my contract ends using
a web form to do so. But in the meantime, I need to get the existing FMP
database totally converted over to Pg.

So today's conversion question, relates to the several lists of checkboxes
in the current FMP database, for keywords under which the images, artists
and exhibitions (it's for an art gallery) are categorized. In FMP, these are
handled by using one field per *set* of checkboxes, with a value list
associated with it that provides the different checkboxes or radio buttons
in the layouts, but stores the data as one long string delimited by some
weird character that doesn't display properly when you export the content as
text.

This works fine in FMP, but my impression from the book I'm currently
reading ("Beginning Databases with PostgreSQL" by Richard Stones and Neil
Matthew) is that in Pg only one type of information should be stored in each
column, so each keyword checkbox should probably be one column. So keeping
the current structure where the keywords in any given set (i.e. subject,
medium, etc.) are all lumped together into one long string for each record
would be considered bad database design and probably make scripting
trickier. But if I make each keyword into a boolean field, I'm not sure how
to display them. From what I've read thus far, the select statements that
you use to display data in Pg usually return the data in the columns, not
the column names. When people ultimately view the database records on the
web, I want them to be able to see something like:

Medium: black and white photograph
Subject: landscape, nature
Processes: hand-tinting, photocollage

Or something to that effect, but NOT:

black and white photograph: yes
landscape: yes
nature: yes
hand-tinting: yes
photocollage: yes

So I'm thinking that probably each set of keywords (medium, subject, etc.)
probably needs to be a table and each keyword a boolean column within it,
but I'm not sure if there's a way to modify a select statement so that it
outputs the names of all columns with a yes/true/1 in them, rather than
outputting the values themselves.

Or even, for that matter, if this really is the best way of doing it or not.
All three of the main data files - artists, exhibitions and images - need to
reference these keywords, so it wouldn't really make sense to include them
within each of those tables (despite the fact that that's currently the way
it's set up in FMP). It seems more logical to make each set a table and then
use a combination of the id number from the artist/image/etc. record plus a
code like "a" for artist, "i" for image and "e" for exhibition as a primary
key to relate each record in the keyword tables back to record the keywords
are describing. Does that make sense? Or is there another way that would be
better?

Sorry for the length of this, but like I said, I'm new to Pg and I wasn't
sure how else to explain it. BTW, I'll be using PHP to create the front end
of this for the web site, if that makes a difference.

Thanks,

Lynna Landstreet
--
Resource Centre Database Coordinator
Gallery 44
www.gallery44.org