CREATE OR REPLACE FUNCTION get_detail(p_table IN VARCHAR2,p_out out sys_refcursor)
RETURN boolean
AS
l_table VARCHAR2(20);
BEGIN
    l_table:=p_table;
IF l_table ='product' THEN
    OPEN p_out  FOR 
    SELECT * FROM product;
elsif l_table ='entity' THEN
    OPEN p_out  FOR 
    SELECT * FROM entity;
END IF;
RETURN TRUE;
exception 
WHEN others THEN
    RETURN FALSE;
    raise_application_error(-20001,substr(sqlerrm,1,100));
END;

set serveroutput on
set echo off
set feedback off
variable var1 varchar2(20);

DECLARE
o_cursor sys_refcursor;
L_productrow  product%ROWTYPE;
L_entityrow   entity%ROWTYPE;

begin
   :var1:=&1;
   if :var1 = 'product' then
      if get_detail('product',o_cursor) then
       loop
		   fetch o_cursor into L_productrow;
			
		   exit when o_cursor%notfound;
		   dbms_output.put_line(L_productrow.product_id||','||L_productrow.CreateDate);
    
       end loop;
      end if;
   elsif :var1='entity' then
    if get_detail('entity',o_cursor) then
       loop
		   fetch o_cursor into L_entityrow;
			
		   exit when o_cursor%notfound;
		   dbms_output.put_line(L_entityrow.entity_id||','||L_entityrow.CreateDate);
    
       end loop;
   end if;
  end if;
exception 
when others then 
   dbms_output.put_line(dbms_utility.format_error_backtrace);
   dbms_output.put_line(sqlerrm);
   
end;
/

ORA-06550: line 7, column 12:
PLS-00357: Table,View Or Sequence reference 'PRODUCT' not allowed in this
context
ORA-06550: line 7, column 4:
PL/SQL: Statement ignored

 37  /
Enter value for 1: emp
old   6:    :var1 := &1;
new   6:    :var1 := emp;
   :var1 := emp;
            *
ERROR at line 6:
ORA-06550: line 6, column 13:
PLS-00357: Table,View Or Sequence reference 'EMP' not allowed in this context
ORA-06550: line 6, column 4:
PL/SQL: Statement ignored


SQL> /
Enter value for 1: 'emp'
old   6:    :var1 := &1;
new   6:    :var1 := 'emp';
SMITH
ALLEN
WARD
JONES
MARTIN
BLAKE
CLARK
SCOTT
KING
TURNER
ADAMS
JAMES
FORD
MILLER
SQL>

when others then 
   dbms_output.put_line(dbms_utility.format_error_backtrace);
   dbms_output.put_line(sqlerrm);