Dynamic execution

Question

Hi all this is Subhanu,
   i have a question please give me code with an example
how to display all the records in a table ,i am passing the table name as in param to the procedure/function
suppose if i pass emp table name it will display 14 rec, if i pass dept it will display 4 records.

Answer 1

You can use a refcursor to do that. But the issue would be for the client in handling the refcursor. Think about it how will it process it if it does not know the exact projection of the returned cursor. You need to come up with a solution like that of the PRINT command in SQL Plus.
Here is a example
You can simply have a Procedure that will return a  refcursor in a output variable like this.
SQL> create or replace procedure print_table
  2  (
  3    p_table_name in varchar2,
  4    p_output    out sys_refcursor
  5  )
  6  as
  7  begin
  8    open p_output for 'select * from ' || p_table_name;
  9  end;
10  /
Procedure created.
Now this is the tricky part. In SQL Plus it looks very easy with the PRINT command. In SQL Plus you just create a variable of type REFCURSOR and pass it to the procedure. Then use the PRINT command to print it.
SQL> var rc_output refcursor
SQL> exec print_table('EMP', :rc_output)
PL/SQL procedure successfully completed.
SQL> print rc_output
     EMPNO ENAME  JOB              MGR HIREDATE         SAL        COM     DEPTNO         ID
      7369 SMITH  CLERK           7902 02-APR-13      12975          0         20
      7499 ALLEN  SALESMAN        7698 20-FEB-13      11600        300         30
      7521 WARD   SALESMAN        7698 22-FEB-13      11250        500         30
      7566 JONES  MANAGER         7839 02-APR-13      12975          0         20
      7654 MARTIN SALESMAN        7698 28-SEP-13      11250       1400         30
      7698 BLAKE  MANAGER         7839 01-MAY-13      12850          0         30
      7782 CLARK  MANAGER         7839 09-JUN-13      12450          0         10
      7788 SCOTT  ANALYST         7566 19-APR-87      13000          0         20
      7839 KING   PRESIDENT            17-NOV-13       5000          0         10
      7844 TURNER SALESMAN        7698 08-SEP-13      11500          0         30
      7876 ADAMS  CLERK           7788 23-MAY-87      11101          0         20
11 rows selected.
SQL> exec print_table('DEPT', :rc_output)
PL/SQL procedure successfully completed.
SQL> print rc_output
    DEPTNO DNAME      LOC
        10 ACCOUNTING NEW YORK
        20 RESEARCH   DALLAS
        30 SALES      CHICAGO
        40 OPERATIONS BOSTON
If you can give more detail on your actual need to do such a thing we could help you better.