[5.4] Use parent connection if related model doesn't specify one

[themsaid]

In reference to this #9355 (comment)

Currently there's no way to query posts on the parent connection "non_default_connection":

User::on('non_default_connection')->first()->posts;

This PR will use the parent model connection if the related model doesn't have a connection specified.

[davisonja]

Is this going to be pushed back into 5.1 LTS as well?
If it resolves #9355 that would be great.

[themsaid]

@davisonja not sure, 5.1 is technically closed for adding features, only bug fixes :)

[taylorotwell]

Just for a reminder, what is the current behavior? It just uses the default connection null I'm guessing? Would there really be any way to fallback to this behavior if you wanted to in 5.4?

[themsaid]

Yes it uses the default connection if not Model $connection was set.

With this PR there's no way to fallback to default no, unless you set the Model $connection to use the default connection. Not null, the default one.

[themsaid]

The reason behind this change is multi-tenancy, to be able to do:

Song::on('band-123')->with('artist')->get();

This will bring the artists of tenant band-123 instead of the ones in the default connection.

[davisonja]

@themsaid True, I still feel it's a bug, though I concede that's primarily as I can't think of a use case for wanting

Song::on('band-123')->with('artist')->get();

to (always) return artists from the default connection; and I am currently using it in a situation where we need the artists to come from 'band-123'.

[BartHuis]

@reno1979

[reno1979]

@themsaid @taylorotwell I would really appreciate this fix.

We 'clone' parts of our database models into multiple connections, and because they are the same we can use our Eloquent Models on each connection.

When working with an eloquent model instance on a specific connection, I did not expect that the related models of that instance would be using the applications default connection. Causing corrupted data in the database or errors.

We 'solved' it for now using a queue on a new thread, that changes the default database connection before the process starts. This is not a real solution and feels like a hack.

We would like to be able to retrieve :

$dataFromConnection1     = $DummyModel::on('connection1')->first();
$relatedDataConnection1  = $RelatedModel::on('connection1')->firstOrCreate(['description'=>'I exist in connection 1']);

$dataFromConnection2     = $DummyModel::on('connection2')->first();
$relatedDataConnection2  = $RelatedModel::on('connection2')->firstOrCreate(['description'=>'I exist in connection 2']);

$dataFromConnection3     = $DummyModel::on('connection3')->first();
$relatedDataConnection3  = $RelatedModel::on('connection3')->firstOrCreate(['description'=>'I exist in connection 3']);

// Attach related data
$dataFromConnection1->relatedData()->attach($relatedDataConnection1);
$dataFromConnection2->relatedData()->attach($relatedDataConnection2);
$dataFromConnection3->relatedData()->attach($relatedDataConnection3);

echo $dataFromConnection1->relatedData()->description;
/* I exist in connection 1 */
echo $dataFromConnection2->relatedData()->description;
/* I exist in connection 2 */
echo $dataFromConnection3->relatedData()->description;
/* I exist in connection 3 */

One note:
The on() method returns a Eloquent Builder instance, thus you should convert it back to the Model instance using getModel(). Is this correct?

It would also fix this issue on the translate extension:

dimsav/laravel-translatable#283

[BartHuis]

@themsaid @taylorotwell what's the status on this one?

[BartHuis]

why only 5.4 and not the current improvements on 5.3? when will 5.4 come out?

[BartHuis]

here: https://laravel-news.com/2016/01/laravel-release-process/ i see it'll be december?

[GrahamCampbell]

Might not be then. Probably more like January, though it's not been decided.

[BartHuis]

@GrahamCampbell why not in the sub updates in 5.3?

[GrahamCampbell]

This is a breaking change so can't go to 5.3.

[BartHuis]

@GrahamCampbell aah, when changing composer to 5.4 we can allready use the development version of 5.4 right? because this is an important one to us...

[reno1979]

We inserted the code from the patch (Eloquent/Model.php) , but can't seem to get it working.

$featureModel = new \App\FeatureGroup;

$featureModel->setConnection('otherConnection');

$featureModel->get();  // Ok we are receiving data from 'otherConnection'


$featureModel->create(['en'=>['name'=>"general"],'nl'=>['name'=>"algemeen"]]); 

// The created row is not in the 'otherConnection', but is placed in the default database.... 

• Note: we are using https://github.com/dimsav/laravel-translatable but when disabled it still inserts to the default db

[themsaid]

@reno1979 but the example you shared doesn't involve related models, which is the purpose of this PR.

Can you please open a new issue with an example on how to generate the issue? But without using a package, just a fresh laravel app cause packages may have changed the default behaviour.

[reno1979]

@themsaid

Thank you for the quick reply.

We are not using any packages at the moment, but the create method keeps using the default db.
Our goal is to fill a related table (translations).

We are using artisan tinker, and tried the following:

\App\FeatureGroup::on('otherConnection')->getModel()->create(['name'=>'test']);
// a new row is inserted in the default db, but should be in the otherConnection db


/* OUR WORKAROUND */

$featureGroupModel = new \App\FeatureGroup;
$featureGroupModel->setConnection('otherConnection');
$featureGroupModel->save();

$featureGroupModel->id; // the given id is from the new table row in otherConnection db :)

[wells]

Here's a helpful hint to setup a base model with this change now in place for 5.4.

If some of your models use an alternate connection, then you can override the default connection while still keeping it for all other models by having them all inherit from this class.

<?php

namespace App;

use Illuminate\Database\Eloquent\Model as BaseModel;

class Model extends BaseModel 
{
    /**
     * Get the current connection name for the model.
     *
     * @return string
     */
    public function getConnectionName()
    {
        return config('database.default');
    }
}