fetch out of sequence

ORA-01002: fetch out of sequence
Cause: In a host language program, a FETCH call was issued out of sequence. A successful parse-and-execute call must be issued before a fetch. This can occur if an attempt was made to FETCH from an active set after all records have been fetched. This may be caused by fetching from a SELECT FOR UPDATE cursor after a commit. A PL/SQL cursor loop implicitly does fetches and may also cause this error.
Action: Parse and execute a SQL statement before attempting to fetch the data.

实际应用及解决方法：
1、在你取完部分数据并执行的过程中，可能有commit或者rollback语句，导致在表t上加的lock被释放掉，再取数据的时候导致出错。

Fetching Across Commits
The FOR UPDATE clause acquires exclusive row locks. All rows are locked when you
open the cursor, and they are unlocked when you commit your transaction. So, you
cannot fetch from a FOR UPDATE cursor after a commit. If you do, PL/SQL raises an
exception. In the following example, the cursor FOR loop fails after the tenth insert:

DECLARE
CURSOR c1 IS SELECT ename FROM emp FOR UPDATE OF sal;
ctr NUMBER := 0;
BEGIN
FOR emp_rec IN c1 LOOP -- FETCHes implicitly
...
ctr := ctr + 1;
INSERT INTO temp VALUES (ctr, ’still going’);
IF ctr >= 10 THEN
COMMIT; -- releases locks
END IF;

END LOOP;
END;

If you want to fetch across commits, do not use the FOR UPDATE and CURRENT OF
clauses. Instead, use the ROWID pseudocolumn to mimic the CURRENT OF clause.
Simply select the rowid of each row into a UROWID variable. Then, use the rowid to
identify the current row during subsequent updates and deletes. An example
follows:
DECLARE
CURSOR c1 IS SELECT ename, job, rowid FROM emp;
my_ename emp.ename%TYPE;
my_job emp.job%TYPE;
my_rowid UROWID;
BEGIN
OPEN c1;
LOOP
FETCH c1 INTO my_ename, my_job, my_rowid;
EXIT WHEN c1%NOTFOUND;
UPDATE emp SET sal = sal * 1.05 WHERE rowid = my_rowid;
-- this mimics WHERE CURRENT OF c1
COMMIT;
END LOOP;
CLOSE c1;
END;
2、禁用自动提交试试。如果你仍然有其他的行在查询的时候也禁用手工提交，当有ｆｏｒ　ｕｐｄａｔｅ游标仍然打开时执行的任何提交可能会造成这个错误。
setAutoCommit(false)