Laravel Eloquent ORM - Many to Many Delete Pivot Table Values left over

Question

Using Laravel, I have the following code

$review = Review::find(1);
$review->delete();

Review has a many to many relationsh

Answer 1

The detach method is used to release a relationship from the pivot table, whilst delete will delete the model record itself i.e. the record in the reviews table. My understanding is that delete won't trigger the detach implicitly. You can use model events to trigger a cleanup of the pivot table, though, using something like:

Review::deleting(function($review)
{
    $review->product()->detach()
}

Also, I would suggest that the relationship would be a one to many, as one product would have many reviews, but one review wouldn't belong to many products (usually).

class Review extends \Eloquent {
    public function product()
    {
        return $this->belongsTo('Product');
    }
}

class Product extends \Eloquent {
    public function reviews()
    {
        return $this->hasMany('Review');
    }
}

Of course, this would then require that you tweak your database structure. If you wanted to leave the database structure and your current relationships as they are, the other option would be to apply a foreign key constraint on the pivot table, such that when either a review or product is removed, you could cascade the delete on the pivot table.

// Part of a database migration
$table->foreign('product_id')->references('id')->on('products')->onDelete('cascade');
$table->foreign('review_id')->references('id')->on('reviews')->onDelete('cascade');

Edit: In adding the constraint, you push the cleanup work onto the database, and don't have to worry about handling it in code.