Check if row exists, Laravel

Question

I have the following db structure:

items:
id, name, user_id

users table:
id, name

user_favorites table:
id, user_id, item_id

On my items permalink pages, I have an 'Add to favorites' button which inserts a new row into user_favorites

I want to be able to replace it for a 'Remove from favorites' button if the user already has it in their favorites.

I can't figure out the logic behind this - do I need to check if a row exists in user_favorites that has the current user's id and the permalink item id? This did not work for me:

if (Auth::user()->id) {
    if (!is_null(DB::table('user_favorites')->where('user_id', '=', Auth::user()->id)->where('item_id', '=', $item->id)->first())) {
        // remove from favorites button will show
    }
}

Solution 1

You may want something like this:

$user_favorites = DB::table('user_favorites')
    ->where('user_id', '=', Auth::user()->id)
    ->where('item_id', '=', $item->id)
    ->first();

if (is_null($user_favorites)) {
    // It does not exist - add to favorites button will show
} else {
    // It exists - remove from favorites button will show
}

Solution 2

I advise you to use exists() or count() to check, not use first().

The fastest way:

$result = DB::table('user_favorites')
    ->where('user_id', '=', Auth::user()->id)
    ->where('item_id', '=', $item->id)
    ->exists();

Or:

$result = DB::table('user_favorites')
    ->where('user_id', '=', Auth::user()->id)
    ->where('item_id', '=', $item->id)
    ->count();

SQL:

select count(*) as aggregate from `user_favorites` where *** limit 1

The faster way: only select id

$result = DB::table('user_favorites')
    ->where('user_id', '=', Auth::user()->id)
    ->where('item_id', '=', $item->id)
    ->first(['id']);

SQL:

select id from `user_favorites` where *** limit 1

The normal way:

$result = DB::table('user_favorites')
    ->where('user_id', '=', Auth::user()->id)
    ->where('item_id', '=', $item->id)
    ->first();

SQL:

select * from `user_favorites` where *** limit 1

Solution 3

Let User_favorite be a model that accesses your user_favorites table

$result = User_favorite::where('user_id',Auth::getUser()->id)
                         ->where('item_id',$item->id)
                         ->first();

if (is_null($result)) {
// Not favorited - add new
    User_favorite::create(['user_id'=>Auth::getUser()->id,'item_id'=>$item->id]);
} else {
// Already favorited - delete the existing
    $result->delete();
}

Solution 4

The simplest way to do is to use toggle() method of many-to-many relationship.

e.g.

$user->roles()->toggle([1, 2, 3]);

The many-to-many relationship also provides a toggle method which "toggles" the attachment status of the given IDs. If the given ID is currently attached, it will be detached. Likewise, if it is currently detached, it will be attached

It also returns an array which tells you if the ID is attached or detached in DB.

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Comments

[TunaMaxx]

Shouldn't if (is_null($user)) { actually be if (is_null($user_favorites)) {

[Simone]

Yeah was a typo, fixed :)

[Tendulraj]

this one is more of eloquent approach

[Ajay Kumar Ganesh]

this is raw method. Using model is better and getting Auth::getUser()->id is faster performance wise.

[Pathros]

When you get that info $user_favorites, how do you check if a specific column is null or not? For example $user_favorites->date

[P_95]

that ->exists() didn't work for me but ->count() worked. (using mysql, L 5.2).

[Datadimension]

how to do this with multiple databases eg where I would select and use connection method how can I find if exists $results = DB::connection("siteDB")->[ exists where id = ???? ]

[DragonFire]

interestingly if you don't put the if and else then you get trying to get property of non object, instead of returning a null (i come from java)