Laravel - Set data to null before deleting column from other table-CodePudding

I have 2 tables. (1) being users, and (2) being foods.

In the [users] table, there is a food_id bracket that is linked as a foreign key to an item/column's id in the other table [foods].

I am able to make a reservation of a [food] column, although I want to be able to press a 'confirm' button on the item once reserved, which will delete the item's targetted column in the Database.

Although since both tables are linked with a foreign key, I know that I need to set the parent key to null in order to be able to fully delete the target column. Otherwise it throws me an error that I can't delete/update a parent item with children objects.

(my food's object primary ID being linked to the authenticated user's food_id foreign key.)

This current code I tried only throws me the following error: "Call to a member function onDelete() on null"

$foodsId = User::find(auth()->user()->foods_id);
$foodsId->onDelete('set null');
$foodsId->save();
    
$foodDel = Foods::find($id);
$foodDel->delete();

Don't exactly know what to think here.

CodePudding user response：

You could edit the foreign key constraint to do this automatically, but what you're trying to do can be done with these lines.

$food = Food::findOrFail(auth()->user()->food_id);
auth()->user()->fill(['food_id' => null])->save(); // use forceFill() if food_id is not in the User's fillable fields.
$food->delete();

To have this happen automatically, you could make a migration with the command

php artisan make:migration changeFoodIdForeignKeyConstraint --table=users

function up()
{
    Schema::table('users', function (Blueprint $table) {
        $table->dropForeign(['food_id']);

        $table->foreign('food_id')
              ->references('id')->on('foods')
              ->onUpdate('cascade')
              ->onDelete('set null');
    });
}

Another option is to use a model event on the Food model

class Food extends Model
{
    /**
     * The "booted" method of the model.
     *
     * @return void
     */
    protected static function booted()
    {
        static::deleting(function ($food) {
            User::where('food_id', $food->id)->update(['food_id' => null]);
        });
    }

CodePudding user response：

Actually have found my own solution. I went to directly target my first foreign key, to then asign a null parameter to it, THEN fetch the targetted ID of my item and delete its column.

$user = auth()->user();
        $user->food_id = null;


        $foodDel = Foods::find($id);
        $foodDel->delete();