SQL & PL/SQL

Hi,

I've been hearing from other developers and DBAs from some time now that doing a

SELECT INTO variable

is slower than doing

OPEN CURSOR FETCH curson_name INTO variable CLOSE CURSOR 

I wasn't convinced, I think letting Oracle do the implicit openning and fetching of the cursor is more efficient. But I've been told that Oracle does a

SELECT COUNT(condition)

before doing the

SELECT INTO variable

to check if the query returns 1 and only 1 row.
So I did a small test on EMP

TONY@RIM> DECLARE
  2  V_DESC EMP.ENAME%TYPE;
  3  BEGIN
  4  SELECT ENAME INTO V_DESC
  5  FROM EMP
  6  WHERE EMPNO = 7788;
  7  DBMS_OUTPUT.PUT_LINE(V_DESC);
  8  END;
  9  /
SCOTT

PL/SQL procedure successfully completed.

Elapsed: 00:00:00.00
TONY@RIM> DECLARE
  2  V_DESC EMP.ENAME%TYPE;
  3  CURSOR C_ENAME IS SELECT ENAME INTO V_DESC
  4  FROM EMP
  5  WHERE EMPNO = 7788;
  6  BEGIN
  7  OPEN C_ENAME;
  8  FETCH C_ENAME INTO V_DESC;
  9  CLOSE C_ENAME;
 10  DBMS_OUTPUT.PUT_LINE(V_DESC);
 11  END;
 12  /
SCOTT

PL/SQL procedure successfully completed.

Elapsed: 00:00:00.00

and no difference, so I did another test on a table with duplicate rows and almost 1 million records.

TONY@RIM> DECLARE
  2  V_DESC ISTD_STOCK_MOUVEMENTS_M.MVTS_B_DESC%TYPE;
  3  BEGIN
  4  SELECT MVTS_B_DESC INTO V_DESC
  5  FROM ISTD_STOCK_MOUVEMENTS_M
  6  WHERE MVTS_DOC_NUM = 215375
  7  AND TMVS_CODE = 'I'
  8  AND MVTS_YEAR = 2005;
  9  DBMS_OUTPUT.PUT_LINE(V_DESC);
 10  END;
 11  /
LEADERS PRODUCTION (HOME +ETS.) / ACHR. 50108

PL/SQL procedure successfully completed.

Elapsed: 00:00:00.00
TONY@RIM> DECLARE
  2  V_DESC ISTD_STOCK_MOUVEMENTS_M.MVTS_B_DESC%TYPE;
  3  CURSOR C_DESC IS
  4  SELECT MVTS_B_DESC
  5  FROM ISTD_STOCK_MOUVEMENTS_M
  6  WHERE MVTS_DOC_NUM = 215375
  7  AND TMVS_CODE = 'I'
  8  AND MVTS_YEAR = 2005;
  9  BEGIN
 10  OPEN C_DESC;
 11  FETCH C_DESC INTO V_DESC;
 12  CLOSE C_DESC;
 13  DBMS_OUTPUT.PUT_LINE(V_DESC);
 14  END;
 15  /
LEADERS PRODUCTION (HOME +ETS.) / ACHR. 50108

PL/SQL procedure successfully completed.

Elapsed: 00:00:00.00
TONY@RIM>

Again no difference.
Can anybody shed some light on this issue? IS it true explicit cursors are faster and better to use rather than SELECT INTO??

Regards,
Tony Garabedian