Question

I have 2 tables: release_servers and release_components
I have a link table release_server_to_components

I right now have it so that each server can have multiple components and that each component can be on multiple servers.

The following are the create statements:

CREATE TABLE `release_components` (
  `id` int(11) NOT NULL auto_increment,
  `buildID` varchar(45) default NULL,
  `svnNumber` varchar(45) NOT NULL,
  `componentType` varchar(45) NOT NULL,
  `release_id` varchar(45) NOT NULL,
  PRIMARY KEY  (`id`)
) ENGINE=MyISAM 

CREATE TABLE `release_servers` (
  `id` int(11) NOT NULL auto_increment,
  `server_name` varchar(45) NOT NULL,
  `server_environment` varchar(45) NOT NULL,
  PRIMARY KEY  (`id`)
) ENGINE=MyISAM

Link table:

CREATE TABLE `release_server_to_components` (
  `id` int(11) NOT NULL auto_increment,
  `release_component_id` int(11) NOT NULL,
  `release_server_id` int(11) NOT NULL,
  PRIMARY KEY  (`id`)
) ENGINE=MyISAM 

What I want to add is the ability to have a system ID — this system ID would be per component on a server (not per server and not per component, but per the component on each server). I want to be able to easily add the system ID per component and insert it into the database.

I can provide code for models and controllers if needed.

Answer 1

You want to “fake” Ruby’s through association with CakePHP.

Why do this over HABTM?

Because you want to save data about the association. With Cake’s HABTM saving data about the association is difficult, because the only thing you really have is a JOIN table. You need something more powerful than this.

First, get rid of the $hasAndBelongsToMany property in your model. Next we’ll be refitting your release_server_to_components table as your “through” table.

So, in ReleaseComponent and ReleaseServer model you would have an association like this:

$hasMany = array('ReleaseServerToComponent');

Now, in your new ReleaseServerToComponent model you would have an association like this:

$belongsTo = array('ReleaseComponent', 'ReleaseServer');

Now, you can access this table just like a normal Cake model, ie $this->ReleaseServer->ReleaseServerToComponent->find(). You can add additional fields to the through table, like server_component_name. You already have a unique identifier for specific, server components with the primary key of the release_server_to_components table.

You could save this data using Cake’s saveAll() method. Alternatively you could generate your own data to save, simply plugging in the server ID and component ID from form fields. At the top of that link is the format saved data should be in when you pass it to the model’s save method.