Best way to apply Eloquent's ORM with Laravel? - php

Question

I have two tables:
treatments (
id,
name
)
companies (
id,
name
)
And I need to build a relation to a "price" table. I thougth in something like follows:
prices (
treatment_id,
company_id,
price
)
But i don know how to apply the ORM to a php aplication. I'm using Laravel with Eloguent's ORM. I think that the real question would be if this is a good way to design the db. Perhaps I should make it diferent?
Any advices?
Thanks,
Ban.

Answer 1

If a Company can have multiple Treatments and a treatment can be bought from multiple companies at different prices, then you have a Many-to-many relationship, with prices being the pivot table (which if you would adhere to convention would be named company_treament, but that's not a must). So you'll need to have two models for Treatments and Companies, which would look like this:
class Company extends \Eloquent {
public function treatments()
{
return $this->belongsToMany('Treatment', 'prices')->withPivot('price');
}
and
class Treatment extends \Eloquent {
public function companies()
{
return $this->belongsToMany('Company', 'prices')->withPivot('price');
}
}
The treatments() and companies() methods from the models are responsible for fetching the related items. Usually the hasMany method only requires the related model as the first parameter, but in your case the pivot table name is non-standard and is set to prices by passing it as the second parameter. Also normally for the pivot table only the relation columns would be fetched (treatment_id and company_id) so you need to specify the the extra column using withPivot. So if you want to get the treatments for a company with the id 1 list you whould to something like this:
$treatments = Company::find(1)->treatments;
The opposite is also true:
$companies = Treatment::find(1)->companies;
If you need to access the price for any of those relations you can do it like this:
foreach ($treatments as $treatment)
{
$price = $treatment->pivot->price;
}
You can read more about how to implement relationships using Eloquent in the Laravel Docs.
EDIT
To insert a relation entry in the pivot table you can use attach and to remove one use detach (for more info read the Docs).
$treatment->companies()->attach($companyId, array('price' => $price));
$treatment->companies()->detach($companyId);
To update a pivot table entry use updateExistingPivot:
$treatment->companies()->updateExistingPivot($companyId, array('price' => $price));