public function init()
    {
        parent::init();
        $this->db = Instance::ensure($this->db, Connection::className());
        if ($this->sql === null) {
            throw new InvalidConfigException('The "sql" property must be set.');
        }
    }
public function init()
    {
        parent::init();
        $this->db = Instance::ensure($this->db, Connection::className());
        if ($this->sql === null) {
            throw new InvalidConfigException('The "sql" property must be set.');
        }
    }
public function init ( ) { parent :: init ( ) ; $ this -> db = Instance :: ensure ( $ this -> db , Connection :: className ( ) ) ; if ( $ this -> sql === null ) { throw new InvalidConfigException ( 'The "sql" property must be set.' ) ; } }
Initializes the DB connection component.
This method will initialize the [[db]] property to make sure it refers to a valid DB connection.
@throws InvalidConfigException if [[db]] is invalid.
Initializes the DB connection component . This method will initialize the [[ db ]] property to make sure it refers to a valid DB connection .