Laravel Foreign Key Integrity constraint violation

Question

I have one foreign key in my database named images.

This is its Migration:

class CreateImagesTable extends Migration
{

    public function up()
    {
        Schema::create('images', function (Blueprint $table) {
            $table->increments('id');
            $table->integer('product_id')->unsigned();
            $table->integer('product_r_id')->unsigned();
            $table->string('name', 50);
            $table->text('images', 50);
            $table->foreign('product_id')->references('id')->on('products')->onDelete('cascade')->onUpdate('cascade');
            $table->timestamps();
        });

        Schema::table('images', function (Blueprint $table) {
            $table->foreign('product_r_id')->references('id')->on('products_r')->onDelete('cascade')->onUpdate('cascade');
        });
    }

    public function down()
    {
        Schema::drop('images');
    }

}

Its Model looks like this:

class Images extends Model
{
    protected $table = 'images';

    protected $fillable = ['product_id', 'product_r_id', 'name', 'images'];

    public function product()
    {
        return $this->belongsTo('App\Product', 'product_id');
    }

    public function productR()
    {
        return $this->belongsTo('App\ProductR', 'product_r_id');
    }

}

ProductR Model looks like this:

class ProductR extends Model
{
    protected $table = 'products_r';

    protected $fillable = ['email', 'title', 'filename', 'inputMpg', 'number_of_chapters'];

    public function images()
    {
        return $this->hasMany('App\Images');
    }

}

And Product Model like this:

class Product extends Model
{
    protected $table = 'products';

    protected $fillable = ['email', 'title', 'filename', 'inputMpg', 'number_of_chapters'];

    public function scenesImages()
    {
        return $this->hasMany('App\Images');
    }
}

So I basicaly try to save in two different forms different products with their image into the same table in my database (images).

Running my Program returns me this error:

QueryException in Connection.php line 655: SQLSTATE[23000]: Integrity constraint violation: 1452 Cannot add or update a child row: a foreign key constraint fails (mydb.images, CONSTRAINT images_product_id_foreign FOREIGN KEY (product_id) REFERENCES products (id) ON DELETE CASCADE ON UPDATE CASCADE) (SQL: insert into images (name, images, product_r_id, updated_at, created_at) values (ki, 0Chrysanthemum.jpg, 10, 2016-05-20 10:50:51, 2016-05-20 10:50:51))

Oliver Adria Oliver Adria · Accepted Answer · 2016-05-20T17:46:39

I think the issue arises because of these lines:

$table->integer('product_id')->unsigned();
[...]
$table->foreign('product_id')->references('id')->on('products')->onDelete('cascade')->onUpdate('cascade');

You cannot just create an image without filling out product_id which seems to be the case because the error

insert into images (name, images, product_r_id, updated_at, created_at) ...

shows that you're inserting into images without product_id which cannot be null and has a foreign key constraint.

I suppose you can do a

$table->integer('product_id')->unsigned()->nullable();

so you don't need to assign it when inserting.

Laravel Foreign Key Integrity constraint violation

1 Answers