firefly-iii/app/Models/Transaction.php

<?php namespace FireflyIII\Models;

use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\SoftDeletes;
use Watson\Validating\ValidatingTrait;

/**
 * Class Transaction
 *
 * @package FireflyIII\Models
 */
class Transaction extends Model
{

    protected $fillable = ['account_id', 'transaction_journal_id', 'description', 'amount'];
    protected $rules
                        = [
            'account_id'             => 'required|exists:accounts,id',
            'transaction_journal_id' => 'required|exists:transaction_journals,id',
            'description'            => 'between:1,255',
            'amount'                 => 'required|numeric'
        ];
    use SoftDeletes, ValidatingTrait;

    /**
     * @return \Illuminate\Database\Eloquent\Relations\BelongsTo
     */
    public function account()
    {
        return $this->belongsTo('FireflyIII\Models\Account');
    }

    /**
     * @return array
     */
    public function getDates()
    {
        return ['created_at', 'updated_at', 'deleted_at'];
    }

    /**
     * @return \Illuminate\Database\Eloquent\Relations\BelongsTo
     */
    public function transactionJournal()
    {
        return $this->belongsTo('FireflyIII\Models\TransactionJournal');
    }
}