Integrity constraint violation in "Many to Many" create - Laravel

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Integrity constraint violation in "Many to Many" create - Laravel

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#1 by (1 votes)

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Context: By registering a company, by being "attached" several clients to it and that same customer can be "attached" in other companies.

I have the following database structure:

Model "Client":

public function enterprises()
{
    return $this->belongsToMany('App\Models\Enterprise', 'enterprise_client');
}

Model "Enterprise":

public function clients()
{
    return $this->belongsToMany('App\Models\Client', 'enterprise_client');
}

Pivot "enterprise_client":

public function up()
{
    Schema::create('enterprise_client', function (Blueprint $table) {
        $table->increments('id');
        $table->integer('enterprise_id')->unsigned();
        $table->foreign('enterprise_id')->references('id')->on('enterprises')->onDelete('restrict');
        $table->integer('client_id')->unsigned();
        $table->foreign('client_id')->references('id')->on('clients')->onDelete('restrict');
        $table->timestamps();
    });
}

To save the data:

if (isset($dataRequest['clients'])) {
            $enterprise->clients()->sync($dataRequest['clients']);
        }

"$ dataRequest ['clients']" is an array of ID's. "isset ()" is to check if you have this array in the Request, because during the registration, filling in clients is not mandatory.

However, when trying to save the data, I get the error:

local.ERROR: PDOException: SQLSTATE[23000]: Integrity constraint violation: 1452 Cannot add or update a child row: a foreign key constraint fails ('my_project'.'enterprise_client', CONSTRAINT 'enterprise_client_client_id_foreign' FOREIGN KEY ('client_id') REFERENCES 'clients' ('id')) in /home/Workspace/MyProject/vendor/doctrine/dbal/lib/Doctrine/DBAL/Driver/PDOStatement.php:142

Using attach() instead of sync() returns the same error.

What could be causing this?

php mysql laravel laravel-eloquent

asked by anonymous 12.12.2018 / 14:54

1 answer

MissingSchemaError: Schema has not been registered for model "Product" How to make a console.log on the map?

score 1 · Answer 1

From what I understand of your problem, only two models are involved (Entreprice and Client), in these cases the hasMany method is used, in the sense that a company can have multiple clients, just as one client can be in several companies. It is a direct relationship between two tables.

The belongsToMany() method is used for relationships with more tables, when you have, for example, a third Pivot table that makes the relationships between clients and companies.

Also, I find that the statements do not have the correct parameters. You should put the ids that make the bindings between the models:

public function enterprises()
{
    return $this->hasMany('App\Models\Enterprise', 'enterprise_id');
}

public function clients()
{
    return $this->hasMany('App\Models\Client', 'client_id');
}

EDIT: I did not really notice the pivot table in the comments, my fault. I simulated all the models and managed to insert the records in the pivot table without problems. I used this code to test:

$enterprise = Enterprise::first();

$dataRequest['clients'][0] = '1';
$dataRequest['clients'][1] = '2';
$dataRequest['clients'][2] = '3';

if (isset($dataRequest['clients'])) {
 $enterprise->clients()->sync($dataRequest['clients']);
}

I had the same error as you when I tried to insert the id of a client that does not exist. For example $dataRequest['clients'][2] = '10';

You can add a try / Catch to work around this problem, the ids that exist are still inserted.

 $enterprise = Enterprise::first();

  $dataRequest['clients'][0] = '1';
  $dataRequest['clients'][1] = '2';
  $dataRequest['clients'][2] = '10';

  if (isset($dataRequest['clients'])) {

        try {
          $enterprise->clients()->sync($dataRequest['clients']);
        } catch (\Exception $e) {
      }
  }