How to set auto increment into non primary key?

问题

How would I set a database auto increment field that is not a primary key on the creation method?

The only way is using a raw query?

DB::statement('ALTER TABLE table CHANGE field field INT(10)AUTO_INCREMENT');

回答1:

It is not implemented to do so. However, I found this over at the Laravel Forums:

Schema::table('table', function(Blueprint $t) {
    // Add the Auto-Increment column
    $t->increments("some_column");

    // Remove the primary key
    $t->dropPrimary("table_some_column_primary");

    // Set the actual primary key
    $t->primary(array("id"));
});

This is not tested but should work. I am not sure about how Laravel calls their primary keys, maybe you have to check that first and adapt the dropPrimary() line in order to make it work.

回答2:

I do not feel safe doing some workaround at migrations, so I did this inside model file:

/**
 *  Setup model event hooks
 */
public static function boot()
{
    parent::boot();
    self::creating(function ($model) {
        $model->field_here = $model->count() + 1;
    });
}

If you want disable autoincrementing add this at the beginning of the model file:

public $incrementing = FALSE;

回答3:

The current answer does not work, auto-incrementing columns must be primary keys. I recommend using firstOrCreate when inserting to get the same level of uniqueness (provided you still want an auto-incrementing key available).

来源：https://stackoverflow.com/questions/42929776/how-to-set-auto-increment-into-non-primary-key

标签

laravel

laravel-migrations

laravel-schema-builder