David Blomstrom wrote:
<>I'm trying to make my first content management system
and am wrestling with a problem that seems to be about
equal parts PHP, Apache mod_rewrite and MySQL. I
wondered if anyone on this list can suggest a MySQL
solution - or partial solution.
I'm dealing with a single database table named
gzanimals that lists animal taxons (orders, families,
species, etc.) in a child-parent relationship (with
fields named "Name" and "Parent". For example:
NAME | PARENT
Animalia | (NULL)
Mammalia | Animalia
Carnivora | Mammalia
Felidae | Carnivora
Panthera | Felidae
leo | Panthera
The code above illustrates the taxonomic hierarchy
linking the lion (Panthera leo) to the animal kingdom
(Animalia). With Apache mod_rewrite, my URL's look
like this:
www.geozoo.org/stacks/Animalia
www.geozoo.org/stacks/Mammalia
www.geozoo.org/stacks/Carnivora
www.geozoo.org/stacks/Felidae
www.geozoo.org/stacks/Panthera
www.geozoo.org/stacks/leo
There are two problems with this strategy:
1. Some species names are shared by more than one
mammal. For example, there's a marsupial named
Antechinus leo.
2. Species are more properly cited with the name of
their parent (genus), so I eventually want my species
URL's to look like this:
www.geozoo.org/stacks/Panthera_leo
* * * * *
I can manipulate my PHP script and mod_rewrite to draw
from two fields and display Panthera_leo instead of
leo.
The problem is that I more or less lose contact with
my database; it recognizes leo as a row identifier,
while Panthera_leo is an unknown.
* * * * *
You can see a good example of what I'm trying to do at
http://www.geozoo.org/stacks/Carnivora Two separate
scripts drive the bread crumbs-style links at the top
of the page and the list of "children" (carnivore
families, in this case) in the column on the right.
If you click Felidae, the children change to a list of
genera that belong to the family Felidae. Click
Panthera - http://www.geozoo.org/stacks/Panthera - and
the children change to species that belong to the
genus Panthera.
As you can see, I've modified these so they display
the genus (parent) + species (child) name, both
physically and in the link. However, they are
nonfunctioning, as I haven't yet figured out how to to
deal with the space between the two values.
* * * * *
At this point, I'm thoroughly confused, especially
since fixes often require tweakingn two or more things
simultaneously - PHP, mod_rewrite and MySQL. But one
thing I haven't experimented with yet is combined
fields.
I created a key on two fields - Name and Parent - and
it NameDual. Is there a way to connect with NameDual
in a PHP script, or is it something that only exists
in my database?
For example, I thought I might change...
$taxon = mysql_query ("SELECT Name, NameCommon, Parent
FROM gzanimals AS GZA
WHERE Parent = '$_GET[taxon]'");
to...
$taxon = mysql_query ("SELECT NameDual, Name,
NameCommon, Parent FROM gzanimals AS GZA
WHERE Parent = '$_GET[taxon]'");
this is dangerous on a real website. see mysql_real_escape_string()
The key just helps you search for the 2 fields at the same time
quicker. It doesn't create a new field. But it's good that you added
that key though since you are looking up both at the same time..
Two fields are always going to be two fields. Perhaps you may be
confusing the role of PHP with that of MySql... Can you just concatenate
the two strings together after you get them from the database? e.g.
$parent.$name? And, just split() or explode() the string when you get
it from the URL?
Can there be spaces in these names? If so, maybe use a dash for space,
that way, there's no chance of ambiguity. Get very familiar with the
PHP string functions too.
-d
--
http://www.douglassdavis.com
