Trying to update integer in database by using increment function in laravel - php

Question

I want to add 1 to my previous karma value in my database.
Here's what I am doing in my controller:-
public function response(Request $request, $id)
{
$globalPost = PublicAnswer::find($id);
if($request->resp == "normal")
{
$answered_by = DB::table('users')
->where('id', $globalPost->answered_by)
->increment('karma', +1);
}
}
Here's my database:-
public function up()
{
Schema::create('users', function (Blueprint $table) {
$table->id();
$table->string('name');
$table->integer('karma')->nullable();
$table->string('email')->unique();
$table->timestamp('email_verified_at')->nullable();
$table->string('password');
$table->rememberToken();
$table->timestamps();
});
}
If I replace increment function with update this is the error that I am getting:-
Argument 1 passed to Illuminate\Database\Query\Builder::update() must be of the type array, string given,
I cannot see any errors and the karma attribute is null.
can anyone tell me whats wrong with my codes.

Answer 1

DB::table('users')
->where('id', $globalPost->answered_by)
returns a Illuminate\Database\Query\Builder ;
Illuminate\Database\Query\Builder has an increment function
public function increment($column, $amount = 1, array $extra = [])
and an update function
public function update(array $values)
so you can try
DB::table('users')
->where('id', $globalPost->answered_by)
->increment('karma');
or this, this would set karma to 1
DB::table('users')
->where('id', $globalPost->answered_by)
->update(['karma'=>1]);
if you want use update set karma=karma+1
use Illuminate\Database\Query\Expression;
DB::table('users')
->where('id', $globalPost->answered_by)
->update(['karma'=>new Expression('karma + 1')]);

Answer 2

According to the docs https://laravel.com/docs/8.x/queries#increment-and-decrement you simply want increment('karma') to increment by 1
The second argument may optionally be passed to control the amount by which the column should be incremented or decremented. You do not need to precede the amount with the plus sign either as increment and decrement mean add or subtract respectively