Why my Laravel on delete cascade is not working?

Might sound like a silly question, but which record are you deleting?

I am deleting Transcation.

public function destroy(Transaction $transaction) { $transaction->delete(); return redirect()->route('transactions.index'); }

Please think about it, buddy. Are you expecting the parent to be deleted when you delete the child? That wouldn't make any sense, would it? You need t delete the payment to delete its child transactions. Not the prher way around.

I expected as much. You have the wrong understanding; the idea of cascading deletes is that whenever the related record is deleted, the corresponding record(s) from this table are deleted also! Your constraint means that whenever a Payment record is deleted, all of the Transaction records that are related by payment_id will be deleted also.

Thanks for explanation. However I had tried to delete payment record in phpMyAdmin and cascading delete was not working too. But now it seems more clear to me. I have two foreign keys in transactions table and that's way it's not working when I'm trying to delete payment.

Schema::create('payments', function (Blueprint $table) {
    $table->bigIncrements('id');
    $table->bigInteger('account_id');
    $table->decimal('amount', 13, 2);
    $table->timestamps();
});

Schema::create('revenues', function (Blueprint $table) {
    $table->bigIncrements('id');
    $table->bigInteger('account_id');
    $table->decimal('amount', 13, 2);
    $table->timestamps();
});

Schema::create('transactions', function (Blueprint $table) {
    $table->bigIncrements('id');
    $table->bigInteger('user_id');
    $table->date('date');
    $table->decimal('amount', 13, 2);
    $table->unsignedBigInteger('payment_id');
    $table->unsignedBigInteger('revenue_id');
    $table->bigInteger('category_id');
    $table->bigInteger('subcategory_id');
    $table->string('remarks')->nullable();
    $table->timestamps();
    $table->foreign('payment_id')->references('id')->on('payments')->onDelete('cascade');
    $table->foreign('revenue_id')->references('id')->on('revenues')->onDelete('cascade');
});

So the better approach is to use delete method in controller and delete both records?

public function destroy(Transaction $transaction)
{
    $transaction->delete();

    $payment = Payment::find($transaction->payment_id);
    $payment->delete();

    $revenue = Revenue::find($transaction->revenue_id);
    $revenue->delete();

    return redirect()->route('transactions.index');
}

No. Deleting either of the related Payment or Revenue records should cause the Transaction to be deleted.

It's not quite sitting right with me that the relationships are this way; can either a Payment or a Revenue model belong to more than one Transaction?

No. My logic works that one payment and one revenue belongs to one transaction. It's a home budget tracker.

Then your keys are wrong. If revenue belongs to transaction then it should have a transaction_id column. Same for revenue. Not the other way around

The belonging to item always has the pointer to the other table

Really appreciate good advice :)

So, this is exactly the point I was making yesterday. The placement of the foreign keys and the Eloquent relationships are indeed backwards according what might be conventional. If it were my app, I would certainly put the FK on the Revenue and Payment models, and define the relationships on the relevant models accordingly.

And what if I have an Event and a related Photo model. In event now I have photo_id, and I want to remove the photo from the db when the event is deleted. In the Photo table I store all kind of models photos (Presenter, Issue, Event, Book, etc.). Now I store the pointers in the other side, not in the Photo. Am I able to has a pointer in the Photo table to the actual table? Is that possible?

Thanks for Your help!