Fed up with myself ( Class::DBI hurts my brain )

silent11 on 2005-07-01T20:43:32

Napoleon: Gosh!

I can't wrap my brain around Class::DBI. I don't think I understand what exactly a has_a is or something. Or maybe it's Friday and it's been a loooooong week.

I'm writing this little code repository script ( that is quite weak) just to get some practice with cdbi.

Here is my module

package Repository::DBI;
        use base 'Class::DBI';
        Repository::DBI->set_db('Main','dbi:mysql:repository','root','mysql');

package Repository::Users;
        use base 'Repository::DBI';
        Repository::Users->table('repository_users');
        Repository::Users->columns(All => qw`users_id users_name users_email users_since users_password`);
        Repository::Users->has_many('entries', "Repository::Entry" => 'entry_user_id');

package Repository::Category;
        use base 'Repository::DBI';
        Repository::Category->table('repository_cat');
        Repository::Category->columns(All => qw`cat_id cat_name cat_description`);
        Repository::Category->has_many('entries', 'Repository::Entry' => 'entry_cat_id');


package Repository::Entry;
        use base 'Repository::DBI';
        Repository::Entry->table('repository_entry');
        Repository::Entry->columns(All => qw`entry_id entry_user_id entry_cat_id entry_code entry_description entry_mod_date entry_create_date`);
        #Repository::Entry->has_a(user => 'Repository::Users');
        #Repository::Entry->has_a(category => 'Repository::Category');

The commented lines are the ones giving me trouble.

And my database:

# category table

CREATE TABLE `repository_cat` (
  `cat_id` int(11) NOT NULL auto_increment,
  `cat_name` varchar(50) default NULL,
  `cat_description` text,
  PRIMARY KEY  (`cat_id`)
) ENGINE=MyISAM;


# entry table

CREATE TABLE `repository_entry` (
  `entry_id` int(11) NOT NULL auto_increment,
  `entry_user_id` int(11) NOT NULL default '0',
  `entry_cat_id` int(11) default NULL,
  `entry_code` longtext,
  `entry_description` text,
  `entry_mod_date` timestamp NOT NULL default CURRENT_TIMESTAMP on update CURRENT_TIMESTAMP,
  `entry_create_date` date default NULL,
  PRIMARY KEY  (`entry_id`)
) ENGINE=MyISAM;

# users table

CREATE TABLE `repository_users` (
  `users_id` int(11) NOT NULL auto_increment,
  `users_name` varchar(50) default NULL,
  `users_email` varchar(225) default NULL,
  `users_since` date default NULL,
  `users_password` varchar(25) default NULL,
  PRIMARY KEY  (`users_id`)
) ENGINE=MyISAM;

My script (below) only works with the last 2 lines in my .pm file commented out.

1 #!/usr/bin/perl
2
3 use strict;
4 use lib '/home/will/lib/';
5 use Repository::DBI;
6
7
8 my $iterator = Repository::Users->retrieve_all;
9 print join("\t",qw/id name email/) , "$/" ;
10 while (my $user = $iterator->next){
11         print join("\t",($user->users_id, $user->users_name, $user->users_email, $/));
12 }
~
~
~

---

Compilation order of CDBI classes

xanthippe on 2005-07-02T00:07:06

If you are defining all of these classes in a single file then you should make sure that you define your Repository::Entry class before defining the Repository::Users and Repository::Category classes.
The CDBI docs states "When setting up the relationship we examine the foreign class's has_a() declarations to discover which of its columns reference our class. (Note that because this happens at compile time, if the foreign class is defined in the same file, the class with the has_a() must be defined earlier than the class with the has_many()." Hope this helps.

Re:Compilation order of CDBI classes

itub on 2005-07-02T03:24:20

Yep, what I ususally do is I leave all the relationships (or at least the has_many) for the end of the file, after defining all the classes.