Convert a string value to a variable

Question

I have faced a problem while writting down the following Pl/SQL block...I want to select the field values dynamically from emp table....
DECLARE
V_COL VARCHAR2(20);
V_COL1 VARCHAR2(20);
TYPE T IS TABLE OF EMP.ENAME%TYPE;
T1 T;
CURSOR C IS
SELECT COLUMN_NAME
FROM ALL_TAB_COLUMNS
WHERE TABLE_NAME ='EMP';
BEGIN
OPEN C;
LOOP
     FETCH C INTO V_COL;
     EXIT WHEN C%NOTFOUND;
FOR NM IN (SELECT V_COL FROM EMP)
     LOOP
     DBMS_OUTPUT.PUT_LINE(NM.V_COL);
     END LOOP;
END LOOP;     
CLOSE C;
END;
But the above trigger gives the following output instead of giving the values of the respective fields:
EMPNO
EMPNO
EMPNO
EMPNO
EMPNO
ENAME
ENAME
ENAME
ENAME
ENAME
ENAME
ENAME
JOB
JOB
JOB
MGR
MGR
MGR
MGR
MGR
MGR
MGR
HIREDATE
HIREDATE
how can i overcome this???

Answer 1

I think he wants to display the contents of a table dynamically.
SQL> create table emp(name varchar2(10),id number(5),salary number(6,2));
Table created.
SQL> insert into emp values('SMITH',1,10.90);
1 row created.
SQL> insert into emp values('TURNER',2,1000);
1 row created.
SQL> insert into emp values('BLACK',3,2000);
1 row created.
SQL> set serveroutput on
SQL> DECLARE
  2  V_COL VARCHAR2(20);
  3  V_COL1 VARCHAR2(20);
  4  CURSOR C IS
  5  SELECT COLUMN_NAME
  6  FROM ALL_TAB_COLUMNS
  7  WHERE TABLE_NAME ='EMP';
  8  TYPE REF_CUR IS REF CURSOR;
  9  NM REF_CUR;
10  COL1 varchar2(1000);
11  BEGIN
12  FOR C1 in C
13  loop
14  open NM for 'SELECT '||c1.COLUMN_NAME ||' FROM EMP WHERE ROWNUM<11';
15  Loop
16  FETCH NM INTO COL1;
17  EXIT WHEN NM%NOTFOUND;
18  DBMS_OUTPUT.PUT_LINE(COL1);
19  END LOOP;
20  CLOSE NM;
21  END LOOP;
22  END;
23  /
SMITH
TURNER
BLACK
1
2
3
10.9
1000
2000
PL/SQL procedure successfully completed.
SQL>