function update( $table, $data, $where = array(), $params = array() ) {

        if ( empty( $data ) ) return;

        $set = array();

        foreach ( $data as $column => $value ) {

            $set[] = $this->quoteIdentifier( $column ) . " = " . $this->quote( $value );

        }

        if ( !is_array( $where ) ) $where = array( $where );
        if ( !is_array( $params ) ) $params = array_slice( func_get_args(), 3 );

        $table = $this->rewriteTable( $table );
        $query = "UPDATE " . $this->quoteIdentifier( $table );
        $query .= " SET " . implode( ", ", $set );
        $query .= $this->getSuffix( $where );

        $this->onQuery( $query, $params );

        $statement = $this->prepare( $query );
        $statement->execute( $params );

        return $statement;

    }