Laravel set incremental id value when seeding table

Question

I'm trying to seed a MySql table using Laravel seeder class. The problem is that it is not assigning the id field (which is an incremental) value as I set. In the seeder class I got:

public function run()
{

    Patropi\Entidade::create([
        'id' => '0',
        'nome' => 'entidade 0',
        'cpfcnpj' => '12345678901'
    ]);

    Patropi\Fornecedor::create([
        'id' => '0',
        'prioridade' => '0'
    ]);
}

On the database, the Fornecedor table id is a foreign key which references the Entidade id, that's why I want to have the same Id on both. The problem is, when it inserts on Entidade it doesn't put it as id = 0 but instead it gives the value of the last incremental + 1. How to force laravel to insert 0 there instead? Thanks in advance.

Answer 1

The reason why it happens is Guarding Attributes. The attributes listed in $guarded array are protected from changes, what means Laravel will ignore all your attempts to modify them. Sometimes this approach is also known as Mass Assignment Protection.

By defualt, Laravel protects "id", so you can't and don't need to set them manually, however there's a way how to stop this default behavior with an unguard() method.

Here's how you can fix your code:

public function run()
{
    Patropi\Entidade::unguard();

    Patropi\Entidade::create([
        'id' => '0',
        'nome' => 'entidade 0',
        'cpfcnpj' => '12345678901'
    ]);

    Patropi\Fornecedor::create([
        'id' => '0',
        'prioridade' => '0'
    ]);
}

Answer 2

Storing NULL or 0 in the auto-incrementing field is one of the triggers to assign the next incremental value.

From the MySQL docs:

You can also explicitly assign 0 to the column to generate sequence numbers.

If you want to disable this functionality, you can turn on the NO_AUTO_VALUE_ON_ZERO sql mode. This will change MySQL so that only assigning NULL will assign the next incremental value, and will allow you to store 0 in the field. From the docs:

NO_AUTO_VALUE_ON_ZERO affects handling of AUTO_INCREMENT columns. Normally, you generate the next sequence number for the column by inserting either NULL or 0 into it. NO_AUTO_VALUE_ON_ZERO suppresses this behavior for 0 so that only NULL generates the next sequence number.

This mode can be useful if 0 has been stored in a table's AUTO_INCREMENT column. (Storing 0 is not a recommended practice, by the way.)

If you don't explicitly need the id to be 0, then I would not try to assign 0. If the id doesn't matter, then you can do this:

public function run()
{
    $entidade = Patropi\Entidade::create([
        'nome' => 'entidade 0',
        'cpfcnpj' => '12345678901'
    ]);

    Patropi\Fornecedor::create([
        'id' => $entidade->id,
        'prioridade' => '0'
    ]);
}

Or, if you have the Eloquent relationships setup:

public function run()
{
    $entidade = Patropi\Entidade::create([
        'nome' => 'entidade 0',
        'cpfcnpj' => '12345678901'
    ]);

    // assumes fornecedor() defines a hasone/hasmany relationship.
    $entidade->fornecedor()->create([
        'prioridade' => '0'
    ]);
}