belongsTo(ChartOfAccount::class, 'parent_id', 'id')->with('parent'); } public function childs() { return $this->hasMany(ChartOfAccount::class, 'parent_id', 'id'); } public function transactions() { return $this->hasMany(Transaction::class, 'chart_of_account_id', 'id'); } public function getBalanceAttribute() { $in = $this->transactions()->where('type', 'in')->sum('amount'); $out = $this->transactions()->where('type', 'out')->sum('amount'); return $in - $out; } }