public function where_str($str = null, $operator = 'OR')
    {
        $this->where .=
            (strlen($this->where) ? " {$operator} " : '')
            .$str;
        return $this;
    }
public function where_str($str = null, $operator = 'OR')
    {
        $this->where .=
            (strlen($this->where) ? " {$operator} " : '')
            .$str;
        return $this;
    }
public function where_str ( $ str = null , $ operator = 'OR' ) { $ this -> where .= ( strlen ( $ this -> where ) ? " {$operator} " : '' ) . $ str ; return $ this ; }
Add a WHERE string to a query

@param string $str The full formed WHERE statement
@param string $operator An operator used if a WHERE statement was already set
@return object The whole object itself for method chaining
Add a WHERE string to a query