Dennis Daupert <[EMAIL PROTECTED]> writes:
> I have a number of tables that contain foreign keys to other tables;
> I need to be able to do selects on multiple tables, specifying
> particular columns in particular tables.
> So far, while combing the DBIx examples, I haven't found a way to do
> something like the query below. How would I do this?
> SELECT quotes.id, quotes.quote, categories.category, users.fname, users.lname
> FROM quotes
> INNER JOIN categories
> ON quotes.category = categories.id
> INNER JOIN users
> ON quotes.author = users.id;
> I'm really trying to wrap my head around the perl data structure way of
> representing SQL statements, but the light bulb hasn't switched on yet.
> I've been looking for a guiding set of rules as to when to use a hash,
> when to use an anonymous array, etc. Is there such?
What I like about the DBIx::Class, from memory so syntax maybe
flubbed. Also did you look at DBIx::Class::Manual::Cookbook ?
$rs=$c->model('YourDB::Quotes')->search();
while($quotes=$rs->next()) {
my $id=$quotes->id;
# grab quotes.id
my $quote=$quotes->quote;
# grab quotes.quote
my $categories=$quotes->category; #
this is really cool, because $categories
# can be used to get any of the data in the table
categories.
# which is why I give it the table name, not the
column name.
my $category_id=$categories->category; # like
category.
}
I also use schema loader, I don't know how much of that accomplishes
the coolness above. I get the sense that it works best if the model
is really well thought out. For example if category is not a foreign
key reference to categories then you can't use that bit of magic
above. I don't know how it handles multi column keys, etc. I think
if you "hand build" your schema then it maybe more forgiving or
perhaps you can cheat a little more, but I have yet to experience this for
myself.
What I don't like about it is complex where clause stuff is tricky,
and not as straight forward as sql syntax, and more prone to errors.
But I'm finding that with $c->model('YourDB')->debug(1); The learning
curve is a lot less steep.
happy hunting,
mojo
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