游标在定义还是打开时读取数据

SET serveroutput ON
DROP TABLE emp2 PURGE;
CREATE TABLE emp2 AS SELECT * FROM emp WHERE 1=2;
DECLARE
V_DEPTNO NUMBER;
CURSOR CUR_EMP2 IS
SELECT * FROM EMP2 WHERE DEPTNO = V_DEPTNO;
BEGIN
DELETE FROM emp2;
V_DEPTNO := 10;
INSERT INTO EMP2
SELECT * FROM EMP WHERE DEPTNO = 10;
FOR CUR IN CUR_EMP2 LOOP
DBMS_OUTPUT.PUT_LINE('deptno:' || TO_CHAR(CUR.DEPTNO) || '  ename:' ||
CUR.ENAME);
END LOOP;
END;
/

SQL> SET serveroutput ON
SQL> DROP TABLE emp2 PURGE;
Table dropped
SQL> CREATE TABLE emp2 AS SELECT * FROM emp WHERE 1=2;
Table created
SQL> DECLARE
2    V_DEPTNO NUMBER;
3    CURSOR CUR_EMP2 IS
4      SELECT * FROM EMP2 WHERE DEPTNO = V_DEPTNO;
5  BEGIN
6    DELETE FROM emp2;
7    V_DEPTNO := 10;
8    INSERT INTO EMP2
9      SELECT * FROM EMP WHERE DEPTNO = 10;
10    FOR CUR IN CUR_EMP2 LOOP
11      DBMS_OUTPUT.PUT_LINE('deptno:' || TO_CHAR(CUR.DEPTNO) || '  ename:' ||
12                           CUR.ENAME);
13    END LOOP;
14  END;
15  /
deptno:10  ename:CLARK
deptno:10  ename:KING
deptno:10  ename:MILLER
PL/SQL procedure successfully completed