title: Laravel only delete a model if no related model exist
body: <p>Lets say i have a model called 'manufacturer' and this model has one to many relation with another model 'vehicle'. Now i dont want to let users delete a manufacturer if there are any vehicles associated with this model.</p>
  
  <pre><code>//In Manufacturer model
  
  public function vehicles()
  {
      return $this-&gt;hasMany('Vehicle');
  }
  </code></pre>
  
  <p>And in the repository/controller i have another method to check for it.</p>
  
  <pre><code>public function checkAssociatedVehicles($id)
  {
      return Manufacturer::with('vehicles')-&gt;find($id)-&gt;toJson();
  }
  </code></pre>
  
  <p><strong>This does outputs the manufacturer data with all the associated vehicles. but this is not efficient, so i just want to check that if there is even one vehicle then dont delete the manufacturer.</strong></p>