'required|between:100,100', ]; public function accountType() { return $this->belongsTo('AccountType'); } public function transactions() { return $this->hasMany('Transaction'); } public function user() { return $this->belongsTo('User'); } /** * Get an accounts current balance. * * @param \Carbon\Carbon $date * * @return float */ public function balance(\Carbon\Carbon $date = null) { $date = is_null($date) ? new \Carbon\Carbon : $date; return floatval($this->transactions()->sum('amount')); } }