/**
* 查找主键
*
* @param mixed $id
* @param array $columns
* @return \CatLib\Database\ActiveRecord\ActiveRecord|null
*/
public function find($id, $columns = ['*'])
{
if (is_array($id)) {
return $this->findMany($id, $columns);
}
$this->builder->where($this->activeRecord->getQualifiedKeyName(), '=', $id);
return $this->first($columns);
}
