Preventing Laravel adding multiple records to a pivot table

php laravel laravel-4 eloquent
Al_ picture Al_ · Jul 4, 2013 · Viewed 49.8k times · Source

I have a many to many relationship set up and working, to add an item to the cart I use:

$cart->items()->attach($item);

Which adds an item to the pivot table (as it should), but if the user clicks on the link again to add an item they have already added it creates a duplicate entry in the pivot table.

Is there a built in way to add a record to a pivot table only if one does not already exist?

If not, how can I check the pivot table to find if a matching record already exists?

Answer

Barryvdh picture Barryvdh · Apr 5, 2014

You can also use the $model->sync(array $ids, $detaching = true) method and disable detaching (the second param).

$cart->items()->sync([$item->id], false);

Update: Since Laravel 5.3 or 5.2.44, you can also call syncWithoutDetaching:

$cart->items()->syncWithoutDetaching([$item->id]);

Which does exactly the same, but more readable :)

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