[Eloquent] Relations doesn't use connection of parent model.

[deftomat]

I try to get models with their relation from connection, which is chosen dynamically:

User::on('another-db')->with('article')->get();

Unfortunately, instance of related model, which is created in the Model::hasMany() function does not contain this connection.

Solution is to modify function as follows:

public function hasMany($related, $foreignKey = null, $localKey = null)
{
    $foreignKey = $foreignKey ?: $this->getForeignKey();

    $instance = new $related;

    // FIX
    if ($instance->getConnection() == null)  {
        $instance->setConnection($this->connection);
    }

    $localKey = $localKey ?: $this->getKeyName();

    return new HasMany($instance->newQuery(), $this, $instance->getTable().'.'.$foreignKey, $localKey);
 }

This solution may be used also in belongsTo(), belongsToMany(), etc.

I can create the pull request, but I think this solution may be undesirable if the user wants to define the relation between the parent model from another-db connection and the related model from default connection. This solution override a default connection in related model.

However, I believe that relations between models from the same database are more likely than relations between models from different databases.

[GrahamCampbell]

What laravel version?

[deftomat]

I try it with 5.1.2 and also with 4.1.*

[WazzaJB]

I am also experiencing this issue, I know this is not intended behaviour as Eloquent/Model.php Line 614 states:

// First we will just create a fresh instance of this model, and then we can
// set the connection on the model so that it is be used for the queries
// we execute, as well as being set on each relationship we retrieve.

I am experiencing this on version 4.2.

At the advise of Joachim Martinsen on Slack, I also tried eager loading the relationships to alleviate this with no success.

[jorgercosta]

Also looking for fix for this

[GrahamCampbell]

Also just ran into this. 4.1

4.1 is not supported.

[GrahamCampbell]

@deftomat That fix you provide looks wrong to me.

[GrahamCampbell]

I am also experiencing this issue, I know this is not intended behaviour as Eloquent/Model.php Line 614 states:

That is for the on method, not for relations.

[GrahamCampbell]

Each model defines it's own connection, and does not try to use that of another model. If you want this behaviour, you need to roll your own relation functions.

[WazzaJB]

Although probably not the best solution to this issue, I did manage to come up with a workaround.

Store the current database, then set the current database to be the database of the relation.

$default = Config::get('database.default');
Config::set('database.default', 'mysql_master');

After you've done your query, reset the current database in current config.

Config::set('database.default', $default);

Hope this helps anyone with a similar issue.

[frdani]

For those who still has this problem:

function relation(){
   $foreignKey = 'fKey';
   $localKey  = 'lKey';

   $instance = new Model();
   $instance->setConnection($this->getConnectionName());

  return new HasOne($instance->newQuery(), $this, $instance->getTable().'.'.$foreignKey, $localKey);
}

I hope it helps!

[frdani]

Of course you will have to adapt that to suit your type of relation....
This should work with eager loading too....
but I still think it would be great to have a documented final solution to this.

[ctrlaltdylan]

Would be great if:

$modelInstance->setConnection('different-database')->relation()->first();

was possible.

[davisonja]

I've just run into this with 5.1 also.

Instead of duplicating the wheel by rolling-your-own relation functions I suggest a method of specifying that related models should inherit (or the parent should propogate, given it seems the appropriate place for the change is in Model.php) the parent's connection. The likes of a 'propogateConnection' flag which is used in belongsTo (etc):

$instance = new $related;
if ($this->propogateConnection) {
    $instance->setConnection($this->getConnectionName());
}

[Frondor]

Why is it closed without a solution? Model relationships aren't inheriting parent's connections, we aren't able to set a connection for them neither

[tannermccoleman]

If model relationships with pivot tables don't inherit a connection shared by both related models, there should at least be a way to set the pivot table or connection dynamically.

[manu144x]

I did a completely unorthodox way, I needed an extremely urgent fix, and since this hasn't been updated for 2 years I just added this line in the Model.php on all the relationship functions:

$instance = new $related;
$instance->setConnection($this->getConnectionName());

And it just works as expected absolutely everywhere, if there is no connection overload, it just uses the default one and that's it.

I think it should be the official fix, but until then I had to commit the Laravel framework folder to my repository, and lock the version in composer.

I hope an official fix will soon arise so I don't have to do these kinds of blasphemy.

[ctrlaltdylan]

@manu144x sometimes the unorthodox solutions are the best solutions!

[reno1979]

I also encountered this issue in 5.3.19 :(

I hope there will be a real fix for this

[reno1979]

@GrahamCampbell @taylorotwell @themsaid @BartHuis

Could this issue please be reopend?
I've encounter multiple issues this week, all caused by this underlying mecanism/issue.

I 'solved' it with changing the default database connection and restoring it, but this is going to introduce unwanted effects eventually.

Adding this 'fix' to relations in a own made model should work:

$instance = new $related;
$instance->setConnection($this->getConnectionName());

When a Laravel extension (which creates relations in your Models etc) is used, this extension should also apply this 'fix'. :(

But a real solution would be much nicer. I saw a proposal for a propegateConnection by @davisonja
Something like that could work. Or similar:

App\myModel::on('mysql2', true); /* True for propegate connection */

[themsaid]

@reno1979 it's not a bug, it's by design.

[BartHuis]

@themsaid and how do you have to work around in our case?

[BartHuis]

@themsaid becouse when you set the connection, and the script fails, your connection stays on the wrong one.

[themsaid]

Currently every model sets its own connection and there's no way to force the parent connection, I'm checking with Taylor if adding such functionality would be a good idea.

[BartHuis]

would be nice, would be a solution for this one also then: dimsav/laravel-translatable#283

[avasa]

I had the same issue when my belongsToMany relationship wasn't working off the parent connection.

My solution was to override the belongsToMany method on the model trying to establish .

See answer below.

http://stackoverflow.com/a/42497184/932696

[BartHuis]

@avasa I didn't read everything yet, but do you use the most recent laravel version? Much things are already fixed...

[Frondor]

This is already implemented on L5.4, although I think it should be optional by setting something like protected $inheritConnection = true; because its annoying to handle some times.

Or better yet, I like reno1979's idea of App\myModel::on('mysql2', true); /* True for propegate connection */

[avasa]

@BartHuis @Frondor I am currently using version 5.2. I will try and update my package. Appriciated the feedback guys.

[fredec]

I could solve with the 1st answer in here: https://laracasts.com/discuss/channels/general-discussion/join-query-with-another-database-connection-model

[JRogaishio]

Sorry to revive a crazy old issue but this still happens in laravel 5.8-7.x.

I've found a possible solution which involves overwriting Illuminate/Database/Eloquent/Concerns/HasRelationships.php newRelatedInstance() method. This can be done in your base model and seems fairly easy.
laravel/ideas#2326