package

CREATE OR REPLACE PACKAGE poly_pkg AS  
  
  FUNCTION describe (p_tbl IN OUT DBMS_TF.TABLE_T )  
    RETURN DBMS_TF.DESCRIBE_T; 
 
  PROCEDURE fetch_rows; 
 
END; 

package body

CREATE OR REPLACE PACKAGE BODY poly_pkg AS  
  
  FUNCTION describe (p_tbl IN OUT DBMS_TF.TABLE_T )  
    RETURN DBMS_TF.DESCRIBE_T AS  
    v_new_col DBMS_TF.COLUMN_METADATA_T;  
    v_new_cols DBMS_TF.COLUMNS_NEW_T;  
  BEGIN  
    -- hide all columns selected  
    FOR counter IN 1..p_tbl.column.count LOOP  
      p_tbl.column(counter).pass_through := FALSE;  
    END LOOP;  
    -- add the rickroll column  
    v_new_col := DBMS_TF.COLUMN_METADATA_T(   
             name => 'RICKROLL' );  
    v_new_cols := DBMS_TF.COLUMNS_NEW_T( 1 => v_new_col);  
    RETURN DBMS_TF.DESCRIBE_T ( new_columns => v_new_cols,  
                                row_replication => true);  
  END;  
  
  PROCEDURE fetch_rows IS  
    l_row_set DBMS_TF.row_set_t;  
    l_new_col DBMS_TF.tab_varchar2_t;  
    l_row_count PLS_INTEGER;  
  BEGIN  
    -- DUAL has one record but we need 6  
    DBMS_TF.ROW_REPLICATION(replication_factor => 6);  
    DBMS_TF.get_row_set(l_row_set, row_count => l_row_count);  
    -- Bring on those heartfelt lyrics!  
    l_new_col(1) := 'Never gonna give you up';  
    l_new_col(2) := 'Never gonna let you down';  
    l_new_col(3) := 'Never gonna run around and desert you';  
    l_new_col(4) := 'Never gonna make you cry';  
    l_new_col(5) := 'Never gonna say goodbye';  
    l_new_col(6) := 'Never gonna tell a lie and hurt you';  
    DBMS_TF.put_col(1, l_new_col);  
  END;  
  
END; 

function

CREATE OR REPLACE FUNCTION poly_func(p_tbl IN TABLE )  
RETURN TABLE PIPELINED  
ROW POLYMORPHIC USING poly_pkg; 

view

CREATE OR REPLACE VIEW dual AS  
SELECT *  
  FROM poly_func(SYS.DUAL) 

select

SELECT *  
  FROM dual