Datamapper (Overzealous Edition), Codeigniter and Has Many Clarification

Question

Firstly, I would like to just it out there that I am an ORM noob. I've never used an ORM in my life and have reached a point in my day-to-day developing that I need to do some crazy advanced relationships that I believe Datamapper Overzealous Edition can help me with as I am using Codeigniter.

In my database I have the following tables;

users
projects
clients
tasks

Here is my desired relationships between the tables;

• A user can belong to many projects.
• A project can have multiple tasks, but can only have one client.
• A client can have many users and can have many projects
• A task can only have one project

I have attempted to set-up my models in the models directory as it says in the documentation the model name without the s on the end, so for users I have a user.php model and so on.

I know the documentation is great, but I just can't seem to understand it properly even though it is obviously very easy. I know you instantiate the model by going for example $u = new User(); inside of your controller, but my question is setting up the relationships inside of the models.

How do I set out my models to have the above relationships so for example when I fetch a task I can see what project it belongs to and a whole heap of information from its associated database tables.

I noticed that in the documentation you use the following inside of the projects model which should tell it that it can have more than one task for a project; var $has_many = array('task')

Is that all there is to it? Is it as simple as defining the $has_many and $has_one variables and putting in the associated model name in the array?

Answer 1

I've never used this particular ORM but I do use Doctrine. If the one you are using works in much the same way then the simple answer to your question is - yes! With Doctrine you set up all relationships in the model classes. The ORM will then manage it all for you. So, for example, if you instantiate a new task object... $task = new Task(); Then you can access the relationship with the Project table by simply writing $task->Project;

I must stress that the above code is not written for datamapper so might not work as is, but I hope it clears things up for you. It sounds like you do understand the documentation but just don't believe it!!!!

Answer 2

That is all you have to do as long as your database structure fits the layout expected by Datamapper Overzealous.

I've been using this ORM in a project I've been building and for the most part, it's been extremely helpful and time saving.