Best Practices: Populating Objects from Database

[mrborisguy]

I've been thinking about this for a little bit. My current context is in web programming, but I think this could be applied to a wider variety of programs.

What, in your opinions, is the best way to populate a list of objects from a database?

In the past, I've done things without classes at all, looking something like this:

while( @info = $sth->fetchrow_array ) {
    $f_name = $info[0];
    $l_name = $info[1];
        ...

    # do what is necessary with these variables.

}

But it seems like there should be a separation of getting all of the information about what could be an object, and what to do with that information. One thought would be something like:

my @objects;
while ( @info = $sth->fetchrow_array ) {
    my $object = Object->new();
    $object->set_fname( $info[0] );
    $object->set_lname( $info[1] );
       ...

    # or

    my $object = Object->new( @info );

    # or

    my $object = Object->new(
        fname => $info[0],
        lname => $info[1], ... );


    push @objects, $object
}

for ( @objects ) {
    # do something with the object
}

Another thought would be to create a sub to populate the objects for me. When I think about this, though, I think about two things, really...

1. Somehow pass an SQL string to the method, but that causes a few problems: the SQL logic would have to return exactly the right fields, but the function wouldn't be able to enforce it; and it doesn't look like you can use placeholders.

   @objects = Object::populate( "SELECT fname, lname, ... FROM object WHE
   +RE title='programmer'" )
   

2. Add some abstraction, so in the options of the subroutine there is a way to specify what objects we want to get (assuming we don't want them all). But that would undoubtedly be less flexible than using SQL.

   @objects = Object::populate( title => "programmer" );
   

Maybe this is a bit of a meditation, but I'm definitely looking for some monks experienced in doing things like this to slap me with some wisdom, so let me know what you've done, and what you think is practically the best solution to populating a list of objects from a database. I'm sure there are some good ways to do this. I hope my question is clear. Thanks!

    -Bryan

[sauoq]

You might want to have a look at Tangram.

[lachoy]

For a good overview of a number of projects that may help you out, check out the Perl Object-Oriented Persistence guide.

[shiza]

Class::DBI or Alzabo may be what you're looking for.

[phaylon]

I'd like to add DBIx-Class to the list.

[pajout]

I think that it very depends on the answer of two questions: Why to store object instances in db and what kind of objects should be stored.
For instance, if you require persistency only, you can do something as my $instance = bless($info[0],$info[1]) or eval() some pieces of this command...