why the decrement not work

@Sinnbeck only empty cell in the table in the blade

@mohammadkhallaf so before the update it says 5, and after it says null? Or

@Sinnbeck https://drive.google.com/file/d/1dBMWMChtY4jUNYWQkc7P1zLzIsXxzmil/view?usp=sharing

@mohammadkhallaf show your database. Your frontend tells me nothing

@Sinnbeck the $remaining mean the result of substract payment from amount

@Sinnbeck https://drive.google.com/file/d/1dBMWMChtY4jUNYWQkc7P1zLzIsXxzmil/view?usp=sharing

<?php

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

return new class extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('finances', function (Blueprint $table) {
            $table->id();
            $table->unsignedBigInteger('customer_id');
            $table->foreign('customer_id')->references('id')->on('customers')->onUpdate('cascade')
            ->onDelete('cascade');
            $table->unsignedBigInteger('test_id');
            $table->foreign('test_id')->references('id')->on('tests')->onUpdate('cascade')
            ->onDelete('cascade');
            // $table->integer('year');
            // $table->integer('month');
            // $table->integer('day');
            $table->integer('amount');
            $table->integer('remaining');
            $table->date('date');
            $table->text('note')->nullable();

            $table->timestamps();
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('finances');
    }
};
<?php

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

return new class extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('finances', function (Blueprint $table) {
            $table->id();
            $table->unsignedBigInteger('customer_id');
            $table->foreign('customer_id')->references('id')->on('customers')->onUpdate('cascade')
            ->onDelete('cascade');
            $table->unsignedBigInteger('test_id');
            $table->foreign('test_id')->references('id')->on('tests')->onUpdate('cascade')
            ->onDelete('cascade');
            // $table->integer('year');
            // $table->integer('month');
            // $table->integer('day');
            $table->integer('amount');
            $table->integer('remaining');
            $table->date('date');
            $table->text('note')->nullable();

            $table->timestamps();
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('finances');
    }
};

<?php

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

return new class extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('transactions', function (Blueprint $table) {
            $table->id();
            $table->unsignedBigInteger('finance_id');
            $table->foreign('finance_id')->references('id')->on('finances')->onUpdate('cascade')
            ->onDelete('cascade');
            $table->integer('payment');
            $table->date('date');
            $table->text('note')->nullable();

            $table->timestamps();
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('transactions');
    }
};

@mohammadkhallaf yes I get wjats meant to happen. I'm interested what actually happens. What are in the variables. How the table row looks before and after the code is run

@Sinnbeck after run the code the $remaining feild assigned to null

@Sinnbeck and the remaining should be updateable after every payment operation

@mohammadkhallaf what does this give you?

dd($request->payment);

@Sinnbeck https://drive.google.com/file/d/1dBMWMChtY4jUNYWQkc7P1zLzIsXxzmil/view?usp=share_link

@Sinnbeck "500" // app\Http\Controllers\TransactionController.php:42

@Sinnbeck https://drive.google.com/file/d/1zgJLvu-wB9a6kmX-1wq_et_kYOgawc-X/view?usp=share_link

@mohammadkhallaf can you share the Finance model

@mohammadkhallaf did you fix it before trying to subtract from it? You cannot subtract from null

@Sinnbeck

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;

class Finance extends Model
{
    use HasFactory;
    //protected $table = 'finance';
    protected $fillable = [
        'id',
        'customer_id',
        'test_id',
        'date',
        'amount',
        'remaining',
        'note',
        'created_at',
        'updated_at'
    ];

    public function customer()
    {
        return $this->belongsTo(Customer::class);
    }

    public function transaction()
    {
        return $this->hasMany(Transaction::class);
    }
}

@Sinnbeck the $remaining doesn't inserted in the form first time it should equal the$amountthen it decremnt by $payment after every payment operation

@mohammadkhallaf buy shouldn't it have a default? Like 0 or 1000?

@Sinnbeck yes the default is $amount

@mohammadkhallaf so in the first controller

            'amount' => $request->amount,
            'remaining' =>  $request->amount, 

@Sinnbeck when i use this

$remaining=  Finance::where('id', $request->finance_id) ->decrement('amount', $request->payment);

the result appear in $amount feild i want it appear in $remaining feild

@mohammadkhallaf yes then set it to the remaining field?

@Sinnbeck how?

@Sinnbeck yes

@Sinnbeck how to get thw result in the $remaining i want the result appear in the $remaining and the $amount doesnt change

@mohammadkhallaf maybe we are not understanding each other completely. If I visit the first controller with amount 500, what would the values of amount and remaining be. And if I visit the second controller with amount 200, what are the values in the database now?

@Sinnbeck at first $amount=500 $remaining=500 then $amount=500 $remaining=300 (500-200)

@Sinnbeck the amount should be decrement by payment and the result appear in remaining 200 is the $payment