Does Laravel Sync Delete and Re-Create? - laravel

Question

I'm looking for some more information on how Laravel Sync Actually works. I have a Relationship Table that contains the following
group_id, user_id, permission, created_at, updated_at
I'm generating an array to pass to the sync command like so.
$groups_array[$group_id] = ['permission' => 0];
When I do this and then call sync it is setting the created_at and updated_at dates on existing relationships to NULL. The desired affect would be to have it just update the permission value to 0 on the existing relationship and not set the created_at and updated_at values to NULL.
It seems as if Sync is deleting everything and just re-creating the relationships based on the array sent. Is there not a way to tell this to update existing relationships vs. deleting and re-creating them?

Answer 1

By default Many to Many relationships in Laravel does not include timestamps, you need to define it on the relationship.
public function users()
{
return $this->belongsToMany(User::class)->withTimestamps();
}

Answer 2

// Post Model
public function categories()
{
return $this->belongsToMany('App\Category')->withTimestamps();
}
public function tags()
{
return $this->belongsToMany('App\Tag')->withTimestamps();
}
// Tag Model
public function posts()
{
return $this->belongsToMany('App\Post')->withTimestamps();
}
// Category Model
public function posts()
{
return $this->belongsToMany('App\Post')->withTimestamps();
}
// Post Controller Update
public function update(Request $request, Post $post)
{
$this->validate($request,[
'title' =>'required',
'categories' => 'required',
'tags' => 'required'
]);
$post->user_id = Auth::id();
$post->title = $request->title;
$post->slug = str_slug($request->title);
$post->save();
$post->categories()->sync($request->categories);
$post->tags()->sync($request->tags);
Toastr::success('Post Successfully Updated:)','Success');
return redirect()->route('admin.post.index');
}
// Delete
public function destroy(Post $post)
{
$post->categories()->detach();
$post->tags()->detach();
$post->delete();
Toastr::success('Post Successfully Deleted :)','Success');
return redirect()->back();
}