Oracle 在过程中使用FOR UPDATE时，应在何时提交？

如果我在存储过程中使用FORUPDATE子句，我应该何时“提交”？关闭打开的光标之后还是关闭打开的光标之前？下面是我使用的程序，我是否以正确的方式操作

CREATE OR REPLACE PROCEDURE Proc_UpdateCSClientCount(inMerid     IN  VARCHAR2,
                                                     outCliCount  OUT NUMBER,
                                                     outretvalue  OUT NUMBER)
AS
   CURSOR c1 IS
      SELECT CLIENT_COUNT
        FROM OP_TMER_CONF_PARENT
       WHERE MER_ID = inMerid
      FOR UPDATE OF CLIENT_COUNT;
BEGIN
   OPEN c1;
   IF SQL%ROWCOUNT = 1 THEN
      FETCH c1 INTO outCliCount;
      outCliCount := outCliCount + 1;
      UPDATE OP_TMER_CONF_PARENT
         SET CLIENT_COUNT = outCliCount
       WHERE CURRENT OF c1;
   END IF;
   outretvalue := 0;
   CLOSE c1;
   COMMIT;
EXCEPTION
   WHEN no_data_found THEN
      outretvalue := -1;
END;

---

如果在关闭游标之前提交，然后再次尝试获取，则会出现无效的\u游标异常。我建议在关闭游标后提交。

发件人：

CREATE OR REPLACE PROCEDURE Proc_UpdateCSClientCount(inMerid     IN  VARCHAR2,
                                                     outCliCount  OUT NUMBER,
                                                     outretvalue  OUT NUMBER)
AS
   CURSOR c1 IS
      SELECT CLIENT_COUNT
        FROM OP_TMER_CONF_PARENT
       WHERE MER_ID = inMerid
      FOR UPDATE OF CLIENT_COUNT;
BEGIN
   OPEN c1;
   IF SQL%ROWCOUNT = 1 THEN
      FETCH c1 INTO outCliCount;
      outCliCount := outCliCount + 1;
      UPDATE OP_TMER_CONF_PARENT
         SET CLIENT_COUNT = outCliCount
       WHERE CURRENT OF c1;
   END IF;
   outretvalue := 0;
   CLOSE c1;
   COMMIT;
EXCEPTION
   WHEN no_data_found THEN
      outretvalue := -1;
END;

打开光标时，所有行都会被锁定，而不是在提取行时锁定。 提交或回滚事务时，将解锁行。 由于行不再被锁定，您无法从FOR获取 提交后更新光标。

CREATE OR REPLACE PROCEDURE Proc_UpdateCSClientCount(inMerid     IN  VARCHAR2,
                                                     outCliCount  OUT NUMBER,
                                                     outretvalue  OUT NUMBER)
AS
   CURSOR c1 IS
      SELECT CLIENT_COUNT
        FROM OP_TMER_CONF_PARENT
       WHERE MER_ID = inMerid
      FOR UPDATE OF CLIENT_COUNT;
BEGIN
   OPEN c1;
   IF SQL%ROWCOUNT = 1 THEN
      FETCH c1 INTO outCliCount;
      outCliCount := outCliCount + 1;
      UPDATE OP_TMER_CONF_PARENT
         SET CLIENT_COUNT = outCliCount
       WHERE CURRENT OF c1;
   END IF;
   outretvalue := 0;
   CLOSE c1;
   COMMIT;
EXCEPTION
   WHEN no_data_found THEN
      outretvalue := -1;
END;

这很重要。如果在关闭光标之前或之后提交，则完成任务（完成获取）并不重要

CREATE OR REPLACE PROCEDURE Proc_UpdateCSClientCount(inMerid     IN  VARCHAR2,
                                                     outCliCount  OUT NUMBER,
                                                     outretvalue  OUT NUMBER)
AS
   CURSOR c1 IS
      SELECT CLIENT_COUNT
        FROM OP_TMER_CONF_PARENT
       WHERE MER_ID = inMerid
      FOR UPDATE OF CLIENT_COUNT;
BEGIN
   OPEN c1;
   IF SQL%ROWCOUNT = 1 THEN
      FETCH c1 INTO outCliCount;
      outCliCount := outCliCount + 1;
      UPDATE OP_TMER_CONF_PARENT
         SET CLIENT_COUNT = outCliCount
       WHERE CURRENT OF c1;
   END IF;
   outretvalue := 0;
   CLOSE c1;
   COMMIT;
EXCEPTION
   WHEN no_data_found THEN
      outretvalue := -1;
END;

但如果需要在抓取之间提交，作为一种解决方法，请使用带rowid的update， 不

，其中当前为

。文档中的示例：

CREATE OR REPLACE PROCEDURE Proc_UpdateCSClientCount(inMerid     IN  VARCHAR2,
                                                     outCliCount  OUT NUMBER,
                                                     outretvalue  OUT NUMBER)
AS
   CURSOR c1 IS
      SELECT CLIENT_COUNT
        FROM OP_TMER_CONF_PARENT
       WHERE MER_ID = inMerid
      FOR UPDATE OF CLIENT_COUNT;
BEGIN
   OPEN c1;
   IF SQL%ROWCOUNT = 1 THEN
      FETCH c1 INTO outCliCount;
      outCliCount := outCliCount + 1;
      UPDATE OP_TMER_CONF_PARENT
         SET CLIENT_COUNT = outCliCount
       WHERE CURRENT OF c1;
   END IF;
   outretvalue := 0;
   CLOSE c1;
   COMMIT;
EXCEPTION
   WHEN no_data_found THEN
      outretvalue := -1;
END;

DECLARE
   CURSOR c1 IS SELECT last_name, job_id, rowid FROM employees;
   my_lastname   employees.last_name%TYPE;
   my_jobid      employees.job_id%TYPE;
   my_rowid      UROWID;
BEGIN
   OPEN c1;
   LOOP
      FETCH c1 INTO my_lastname, my_jobid, my_rowid;
      EXIT WHEN c1%NOTFOUND;
      UPDATE employees SET salary = salary * 1.02 WHERE rowid = my_rowid;
      -- this mimics WHERE CURRENT OF c1
      COMMIT;
   END LOOP;
   CLOSE c1;
END;
/

更新（编辑问题后）：您可以在一个sql中完成此操作，无需光标

CREATE OR REPLACE PROCEDURE Proc_UpdateCSClientCount(inMerid     IN  VARCHAR2,
                                                     outCliCount  OUT NUMBER,
                                                     outretvalue  OUT NUMBER)
AS
   CURSOR c1 IS
      SELECT CLIENT_COUNT
        FROM OP_TMER_CONF_PARENT
       WHERE MER_ID = inMerid
      FOR UPDATE OF CLIENT_COUNT;
BEGIN
   OPEN c1;
   IF SQL%ROWCOUNT = 1 THEN
      FETCH c1 INTO outCliCount;
      outCliCount := outCliCount + 1;
      UPDATE OP_TMER_CONF_PARENT
         SET CLIENT_COUNT = outCliCount
       WHERE CURRENT OF c1;
   END IF;
   outretvalue := 0;
   CLOSE c1;
   COMMIT;
EXCEPTION
   WHEN no_data_found THEN
      outretvalue := -1;
END;

UPDATE OP_TMER_CONF_PARENT 
set CLIENT_COUNT = CLIENT_COUNT +1 
where MER_ID = inMerid;

更新2。代码应更新如下，以便正常工作：

CREATE OR REPLACE PROCEDURE Proc_UpdateCSClientCount(inMerid     IN  VARCHAR2,
                                                     outCliCount  OUT NUMBER,
                                                     outretvalue  OUT NUMBER)
AS
   CURSOR c1 IS
      SELECT CLIENT_COUNT
        FROM OP_TMER_CONF_PARENT
       WHERE MER_ID = inMerid
      FOR UPDATE OF CLIENT_COUNT;
BEGIN
   OPEN c1;
   IF SQL%ROWCOUNT = 1 THEN
      FETCH c1 INTO outCliCount;
      outCliCount := outCliCount + 1;
      UPDATE OP_TMER_CONF_PARENT
         SET CLIENT_COUNT = outCliCount
       WHERE CURRENT OF c1;
   END IF;
   outretvalue := 0;
   CLOSE c1;
   COMMIT;
EXCEPTION
   WHEN no_data_found THEN
      outretvalue := -1;
END;

...
open C1;
FETCH C1 into OUTCLICOUNT;
--dbms_output.put_line(' count:'||c1%rowcount);
IF c1%rowcount = 1 THEN
      outCliCount := outCliCount + 1;
...

也就是说：在对受影响的行进行计数之前，应该先进行提取，受影响的行是

c1%rowcount

，而不是

sql%rowcount

。

---

如果您想知道某一行是否已更新，则应将else设置为If，并为outretvalue参数指定一个特殊值。

您应在事务结束时提交。我怀疑你能找到一个合理的情况，交易的结尾是在<代码>的中间，更新< <代码>循环> < /p>

CREATE OR REPLACE PROCEDURE Proc_UpdateCSClientCount(inMerid     IN  VARCHAR2,
                                                     outCliCount  OUT NUMBER,
                                                     outretvalue  OUT NUMBER)
AS
   CURSOR c1 IS
      SELECT CLIENT_COUNT
        FROM OP_TMER_CONF_PARENT
       WHERE MER_ID = inMerid
      FOR UPDATE OF CLIENT_COUNT;
BEGIN
   OPEN c1;
   IF SQL%ROWCOUNT = 1 THEN
      FETCH c1 INTO outCliCount;
      outCliCount := outCliCount + 1;
      UPDATE OP_TMER_CONF_PARENT
         SET CLIENT_COUNT = outCliCount
       WHERE CURRENT OF c1;
   END IF;
   outretvalue := 0;
   CLOSE c1;
   COMMIT;
EXCEPTION
   WHEN no_data_found THEN
      outretvalue := -1;
END;

也许你听说过频繁地承诺是一件好事。这是一个错误的神话，这是。Oracle中的情况正好相反：提交涉及额外的工作，因此您应该只在所有工作完成时提交，而不是之前

CREATE OR REPLACE PROCEDURE Proc_UpdateCSClientCount(inMerid     IN  VARCHAR2,
                                                     outCliCount  OUT NUMBER,
                                                     outretvalue  OUT NUMBER)
AS
   CURSOR c1 IS
      SELECT CLIENT_COUNT
        FROM OP_TMER_CONF_PARENT
       WHERE MER_ID = inMerid
      FOR UPDATE OF CLIENT_COUNT;
BEGIN
   OPEN c1;
   IF SQL%ROWCOUNT = 1 THEN
      FETCH c1 INTO outCliCount;
      outCliCount := outCliCount + 1;
      UPDATE OP_TMER_CONF_PARENT
         SET CLIENT_COUNT = outCliCount
       WHERE CURRENT OF c1;
   END IF;
   outretvalue := 0;
   CLOSE c1;
   COMMIT;
EXCEPTION
   WHEN no_data_found THEN
      outretvalue := -1;
END;

此外，从逻辑的角度来看，如果您可以从头开始而不是完成一半的工作，那么从错误中恢复是难以想象的容易

CREATE OR REPLACE PROCEDURE Proc_UpdateCSClientCount(inMerid     IN  VARCHAR2,
                                                     outCliCount  OUT NUMBER,
                                                     outretvalue  OUT NUMBER)
AS
   CURSOR c1 IS
      SELECT CLIENT_COUNT
        FROM OP_TMER_CONF_PARENT
       WHERE MER_ID = inMerid
      FOR UPDATE OF CLIENT_COUNT;
BEGIN
   OPEN c1;
   IF SQL%ROWCOUNT = 1 THEN
      FETCH c1 INTO outCliCount;
      outCliCount := outCliCount + 1;
      UPDATE OP_TMER_CONF_PARENT
         SET CLIENT_COUNT = outCliCount
       WHERE CURRENT OF c1;
   END IF;
   outretvalue := 0;
   CLOSE c1;
   COMMIT;
EXCEPTION
   WHEN no_data_found THEN
      outretvalue := -1;
END;

在国际海事组织，在程序中作出承诺的情况应该非常罕见。调用应用程序应该是进行必要检查并最终决定是否提交数据的应用程序

CREATE OR REPLACE PROCEDURE Proc_UpdateCSClientCount(inMerid     IN  VARCHAR2,
                                                     outCliCount  OUT NUMBER,
                                                     outretvalue  OUT NUMBER)
AS
   CURSOR c1 IS
      SELECT CLIENT_COUNT
        FROM OP_TMER_CONF_PARENT
       WHERE MER_ID = inMerid
      FOR UPDATE OF CLIENT_COUNT;
BEGIN
   OPEN c1;
   IF SQL%ROWCOUNT = 1 THEN
      FETCH c1 INTO outCliCount;
      outCliCount := outCliCount + 1;
      UPDATE OP_TMER_CONF_PARENT
         SET CLIENT_COUNT = outCliCount
       WHERE CURRENT OF c1;
   END IF;
   outretvalue := 0;
   CLOSE c1;
   COMMIT;
EXCEPTION
   WHEN no_data_found THEN
      outretvalue := -1;
END;

总之，您不能为UPDATE提交accross

（它将产生一个
ORA-01002:fetch-out-sequence
），这是一件好事。每当您发现自己在一个普通循环中提交ACC时，您应该问问自己提交是否真的是必要的——很可能不是

CREATE OR REPLACE PROCEDURE Proc_UpdateCSClientCount(inMerid     IN  VARCHAR2,
                                                     outCliCount  OUT NUMBER,
                                                     outretvalue  OUT NUMBER)
AS
   CURSOR c1 IS
      SELECT CLIENT_COUNT
        FROM OP_TMER_CONF_PARENT
       WHERE MER_ID = inMerid
      FOR UPDATE OF CLIENT_COUNT;
BEGIN
   OPEN c1;
   IF SQL%ROWCOUNT = 1 THEN
      FETCH c1 INTO outCliCount;
      outCliCount := outCliCount + 1;
      UPDATE OP_TMER_CONF_PARENT
         SET CLIENT_COUNT = outCliCount
       WHERE CURRENT OF c1;
   END IF;
   outretvalue := 0;
   CLOSE c1;
   COMMIT;
EXCEPTION
   WHEN no_data_found THEN
      outretvalue := -1;
END;

如果确实需要提交并且只获取一次，那么在关闭光标之前还是之后提交都无所谓

CREATE OR REPLACE PROCEDURE Proc_UpdateCSClientCount(inMerid     IN  VARCHAR2,
                                                     outCliCount  OUT NUMBER,
                                                     outretvalue  OUT NUMBER)
AS
   CURSOR c1 IS
      SELECT CLIENT_COUNT
        FROM OP_TMER_CONF_PARENT
       WHERE MER_ID = inMerid
      FOR UPDATE OF CLIENT_COUNT;
BEGIN
   OPEN c1;
   IF SQL%ROWCOUNT = 1 THEN
      FETCH c1 INTO outCliCount;
      outCliCount := outCliCount + 1;
      UPDATE OP_TMER_CONF_PARENT
         SET CLIENT_COUNT = outCliCount
       WHERE CURRENT OF c1;
   END IF;
   outretvalue := 0;
   CLOSE c1;
   COMMIT;
EXCEPTION
   WHEN no_data_found THEN
      outretvalue := -1;
END;


在代码节选后更新：代码中有许多地方需要更正（我想这不是直接的生产代码，但仍然是）：

CREATE OR REPLACE PROCEDURE Proc_UpdateCSClientCount(inMerid     IN  VARCHAR2,
                                                     outCliCount  OUT NUMBER,
                                                     outretvalue  OUT NUMBER)
AS
   CURSOR c1 IS
      SELECT CLIENT_COUNT
        FROM OP_TMER_CONF_PARENT
       WHERE MER_ID = inMerid
      FOR UPDATE OF CLIENT_COUNT;
BEGIN
   OPEN c1;
   IF SQL%ROWCOUNT = 1 THEN
      FETCH c1 INTO outCliCount;
      outCliCount := outCliCount + 1;
      UPDATE OP_TMER_CONF_PARENT
         SET CLIENT_COUNT = outCliCount
       WHERE CURRENT OF c1;
   END IF;
   outretvalue := 0;
   CLOSE c1;
   COMMIT;
EXCEPTION
   WHEN no_data_found THEN
      outretvalue := -1;
END;


将永远不会引发异常：只有隐式
选择进入
才能生成
未找到数据
如果前面的语句是
SELECT
，则
SQL%ROWCOUNT
为空
您可以使用
c1%ROWCOUNT
，但这只会在初始
打开后返回获取的行数：
0

我主要使用
更新NOWAIT
，这样两个会话就不会互相阻塞。如果只使用
进行更新
，则最好使用单个
更新
，而不要事先使用
选择
这是一个偏好问题，但返回代码容易出错和丢失。让错误传播。为什么有人会对一个不存在的
id
调用此函数？这可能是调用应用程序/过程中的错误，因此您不应该捕获它

所以你可以像这样重写你的程序：

CREATE OR REPLACE PROCEDURE Proc_UpdateCSClientCount(inMerid     IN  VARCHAR2,
                                                     outCliCount  OUT NUMBER,
                                                     outretvalue  OUT NUMBER)
AS
   CURSOR c1 IS
      SELECT CLIENT_COUNT
        FROM OP_TMER_CONF_PARENT
       WHERE MER_ID = inMerid
      FOR UPDATE OF CLIENT_COUNT;
BEGIN
   OPEN c1;
   IF SQL%ROWCOUNT = 1 THEN
      FETCH c1 INTO outCliCount;
      outCliCount := outCliCount + 1;
      UPDATE OP_TMER_CONF_PARENT
         SET CLIENT_COUNT = outCliCount
       WHERE CURRENT OF c1;
   END IF;
   outretvalue := 0;
   CLOSE c1;
   COMMIT;
EXCEPTION
   WHEN no_data_found THEN
      outretvalue := -1;
END;

CREATE OR REPLACE PROCEDURE Proc_UpdateCSClientCount(inMerid     IN  VARCHAR2, 
                                                     outCliCount OUT NUMBER) AS
BEGIN
   -- lock the row, an exception will be raised if this row is locked
   SELECT CLIENT_COUNT + 1
     INTO outCliCount
     FROM OP_TMER_CONF_PARENT
    WHERE MER_ID = inMerid
   FOR UPDATE OF CLIENT_COUNT NOWAIT;
   -- update the row
   UPDATE OP_TMER_CONF_PARENT
      SET CLIENT_COUNT = CLIENT_COUNT + 1
    WHERE MER_ID = inMerid;
END;

：跨提交获取可能会导致可怕的
ORA-1555错误
是的，但这里的情况并非如此。在for update cursors中，您不能在提交之间获取。是的，这对我来说很清楚，但您提供的解决方案可能会导致ORA-1555问题，可能是为了实现这个say GTT表还有其他一些工作。哦，我明白了，我刚刚从文档中给出了一个解决方案。但用户甚至没有要求在抓取之间提交。他只想知道谁是第一个接近的人，谁是第一个承诺的人：）。所以我认为我们不应该深入研究fetch问题：）：好的，没问题，我只是想到了它的缺点：）这似乎是一个小任务的大量代码。您能否不运行更新，将新的客户端计数返回到一个变量中？更少的代码，更少的错误，更快的性能。嗨，vincent，1。如果我使用“不等待”，其他会话无法获取同一行，它将抛出错误，但我需要其他会话来获取（选择），但不能同时更新同一行。2.是否可以使用不带游标的FOR UPDATE子句？3.在获取自身或增加客户端计数时，如果Mer_id不存在，会发生什么？4.如果在获取c1后使用c1%ROWCOUNT，它会返回受影响的行数吗？1）在Oracle中。2） 您必须关闭显式游标，而不是。3） 它将引发未找到的数据，这很好，如果不是错误，呼叫应用程序可以处理它。4） 不要对隐式游标使用fetch。如果使用提取的显式光标，请在提取后使用
c1%ROWCOUNT
。