将 Cursor 语句从 SQL Server 转换为 Oracle 不起作用答案

【问题标题】：Converting Cursor statement from SQL Server to Oracle doesn't work将 Cursor 语句从 SQL Server 转换为 Oracle 不起作用
【发布时间】：2016-06-08 08:57:29
【问题描述】：

我使用游标将所有记录从表 CUT_CALENDAR 移动到 SD_CALENDAR（日历迁移）。为此，我在 Sql Server 上使用以下光标：

DECLARE @sdCalendarId NUMERIC(20)
DECLARE @calendarTypId NUMERIC(5)
DECLARE @name NVARCHAR(35)
DECLARE @description NVARCHAR(255)
DECLARE @ptyId NUMERIC(20)
DECLARE @lockCode NVARCHAR(20)
DECLARE @dataOwnerId NUMERIC(20)
DECLARE @cntId NUMERIC(20)
DECLARE @nonBusinessDaysMonday CHAR(1)
DECLARE @nonBusinessDaysTuesday CHAR(1)
DECLARE @nonBusinessDaysWednesday CHAR(1)
DECLARE @nonBusinessDaysThursday CHAR(1)
DECLARE @nonBusinessDaysFriday CHAR(1)
DECLARE @nonBusinessDaysSaturday CHAR(1)
DECLARE @nonBusinessDaysSunday CHAR(1)
DECLARE @ccyId NUMERIC(20)
DECLARE @code NVARCHAR(30)
DECLARE @version NUMERIC(10)
DECLARE @seal VARCHAR(255)
DECLARE @lstUpdTs DATETIME



DECLARE cursorCutoffCalendar CURSOR FOR
  SELECT ID, NAME, CALENDAR_TYP_ID,DESCRIPTION,'Y',PTY_ID,LOCK_CODE,DATA_OWNER_ID,CNT_ID,NON_BUSINESS_DAYS_MONDAY,NON_BUSINESS_DAYS_TUESDAY,NON_BUSINESS_DAYS_WEDNESDAY,NON_BUSINESS_DAYS_THURSDAY,NON_BUSINESS_DAYS_FRIDAY,NON_BUSINESS_DAYS_SATURDAY,NON_BUSINESS_DAYS_SUNDAY,CCY_ID,CODE,VERSION,SEAL,LST_UPD_TS
  FROM CUT_CALENDAR
  WHERE ID != 1

OPEN cursorCutoffCalendar
FETCH NEXT FROM cursorCutoffCalendar INTO @sdCalendarId, @calendarTypId, @name, @description, @ptyId, @lockCode, @dataOwnerId, @cntId, @nonBusinessDaysMonday, @nonBusinessDaysTuesday, @nonBusinessDaysWednesday, @nonBusinessDaysThursday, @nonBusinessDaysFriday, @nonBusinessDaysSaturday, @nonBusinessDaysSunday, @nonBusinessDaysMonday, @ccyId, @code, @version, @seal, @lstUpdTs
WHILE @@FETCH_STATUS = 0
BEGIN
    SELECT @sdCalendarId = COALESCE(MAX(ID),1) FROM SD_CALENDAR

    SET @sdCalendarId = @sdCalendarId + 1

    INSERT INTO SD_CALENDAR (ID, NAME, CALENDAR_ROLE_ID,DESCRIPTION,USE_IN_CUTOFF,PTY_ID,LOCK_CODE,DATA_OWNER_ID,CNT_ID,NON_BUSINESS_DAYS_MONDAY,NON_BUSINESS_DAYS_TUESDAY,NON_BUSINESS_DAYS_WEDNESDAY,NON_BUSINESS_DAYS_THURSDAY,NON_BUSINESS_DAYS_FRIDAY,NON_BUSINESS_DAYS_SATURDAY,NON_BUSINESS_DAYS_SUNDAY,CCY_ID,CODE,VERSION,SEAL,LST_UPD_TS)
    VALUES(@sdCalendarId, @name, @calendarTypId,@description,'Y',@ptyId,@lockCode,@dataOwnerId,@cntId,@nonBusinessDaysMonday,@nonBusinessDaysTuesday,@nonBusinessDaysWednesday,@nonBusinessDaysThursday,@nonBusinessDaysFriday,@nonBusinessDaysSaturday,@nonBusinessDaysSunday,@ccyId,@code,@version,@seal,@lstUpdTs)
END
CLOSE cursorCutoffCalendar
DEALLOCATE cursorCutoffCalendar
GO

因为我也想支持Oracle架构，所以我尝试将这个SqlServer游标转换为如下Oracle游标：

    DECLARE v_sdCalendarId NUMERIC(20);
     v_calendarTypId NUMERIC(5);
     v_name VARCHAR2(35);
     v_description VARCHAR2(255);
     v_ptyId NUMERIC(20);
     v_lockCode VARCHAR2(20);
     v_dataOwnerId NUMERIC(20);
     v_cntId NUMERIC(20);
     v_nonBusinessDaysMonday CHAR(1);
     v_nonBusinessDaysTuesday CHAR(1);
     v_nonBusinessDaysWednesday CHAR(1);
     v_nonBusinessDaysThursday CHAR(1);
     v_nonBusinessDaysFriday CHAR(1);
     v_nonBusinessDaysSaturday CHAR(1);
     v_nonBusinessDaysSunday CHAR(1);
     v_ccyId NUMERIC(20);
     v_code VARCHAR2(30);
     v_version NUMERIC(10);
     v_seal VARCHAR(255);
     v_lstUpdTs DATE;
    CURSOR cursorCutoffCalendar IS
        SELECT ID, NAME, CALENDAR_TYP_ID,DESCRIPTION,'Y',PTY_ID,LOCK_CODE,DATA_OWNER_ID,CNT_ID,NON_BUSINESS_DAYS_MONDAY,NON_BUSINESS_DAYS_TUESDAY,NON_BUSINESS_DAYS_WEDNESDAY,NON_BUSINESS_DAYS_THURSDAY,NON_BUSINESS_DAYS_FRIDAY,NON_BUSINESS_DAYS_SATURDAY,NON_BUSINESS_DAYS_SUNDAY,CCY_ID,CODE,VERSION,SEAL,LST_UPD_TS
        FROM CUT_CALENDAR
        WHERE ID != 1;

 BEGIN
    FOR calendar IN cursorCutoffCalendar
    LOOP
        SELECT COALESCE(MAX(ID),1) into v_sdCalendarId from SD_CALENDAR;

                    INSERT INTO SD_CALENDAR (ID, NAME, CALENDAR_ROLE_ID,DESCRIPTION,USE_IN_CUTOFF,PTY_ID,LOCK_CODE,DATA_OWNER_ID,CNT_ID,NON_BUSINESS_DAYS_MONDAY,NON_BUSINESS_DAYS_TUESDAY,NON_BUSINESS_DAYS_WEDNESDAY,NON_BUSINESS_DAYS_THURSDAY,NON_BUSINESS_DAYS_FRIDAY,NON_BUSINESS_DAYS_SATURDAY,NON_BUSINESS_DAYS_SUNDAY,CCY_ID,CODE,VERSION,SEAL,LST_UPD_TS)
                    VALUES(v_sdCalendarId, v_name, v_calendarTypId,v_description,'Y',v_ptyId,v_lockCode,v_dataOwnerId,v_cntId,v_nonBusinessDaysMonday,v_nonBusinessDaysTuesday,v_nonBusinessDaysWednesday,v_nonBusinessDaysThursday,v_nonBusinessDaysFriday,v_nonBusinessDaysSaturday,v_nonBusinessDaysSunday,v_ccyId,v_code,v_version,v_seal,v_lstUpdTs);
    END LOOP;
CLOSE cursorCutoffCalendar;

END;
/

ORA-01001: 无效游标 ORA-06512: 在第 34 行

我的 oracle 光标脚本有什么问题？

【问题讨论】：

标签： sql-server oracle cursor

【解决方案1】：

您的程序有很多问题：

您正在获取一个游标，但您没有将值存储在任何地方。这是你的错误的原因。您需要将值提取到游标行类型变量或单个变量中。
如果您绝对必须对游标执行循环，则使用 CURSOR FOR LOOP 会容易得多。
您正在使用 max(val) + 1 来填充（可能）唯一的 id 列。这不是您应该做的事情——尤其是在有其他并发事务的情况下。相反，您应该使用一个序列，例如：

create sequence sd_calendar_seq
  START WITH 261 -- something that's higher than the max id of sd_calendar
  MAXVALUE 999999999999999999999999999
  MINVALUE 1
  NOCYCLE
  CACHE 20
  NOORDER;

您根本不需要用于循环的游标——事实上，这样做的速度很慢。您可以只使用一个插入语句一举完成所有工作：

insert into sd_calendar (id,
                         name,
                         calendar_role_id,
                         description,
                         use_in_cutoff,
                         pty_id,
                         lock_code,
                         data_owner_id,
                         cnt_id,
                         non_business_days_monday,
                         non_business_days_tuesday,
                         non_business_days_wednesday,
                         non_business_days_thursday,
                         non_business_days_friday,
                         non_business_days_saturday,
                         non_business_days_sunday,
                         ccy_id,
                         code,
                         version,
                         seal,
                         lst_upd_ts)
  SELECT sd_calendar_seq.nextval,
         name,
         calendar_typ_id,
         description,
         'Y',
         pty_id,
         lock_code,
         data_owner_id,
         cnt_id,
         non_business_days_monday,
         non_business_days_tuesday,
         non_business_days_wednesday,
         non_business_days_thursday,
         non_business_days_friday,
         non_business_days_saturday,
         non_business_days_sunday,
         ccy_id,
         code,
         version,
         seal,
         lst_upd_ts
  from   cut_calendar
  where  id != 1;

查看您更新的代码，还有一些其他问题：

您选择变量的语法不正确。相反，它应该是：select coalesce(max(id),1) into v_sdcalendarid from sd_calendar;
您设置变量值的语法不正确。应该是v_sdcalendarid := v_sdcalendarid + 1;
现在您已经定义了游标记录 (calendar)，您不需要所有单独的变量。此外，您需要更改要插入的值以引用记录字段。
当您使用游标进行循环时，您无需显式打开或关闭游标。

这意味着您的代码应该类似于：

declare
  v_sdcalendarid numeric (20);

  cursor cursorcutoffcalendar
  is
    select id,
           name,
           calendar_typ_id,
           description,
           'Y' use_in_cutoff,
           pty_id,
           lock_code,
           data_owner_id,
           cnt_id,
           non_business_days_monday,
           non_business_days_tuesday,
           non_business_days_wednesday,
           non_business_days_thursday,
           non_business_days_friday,
           non_business_days_saturday,
           non_business_days_sunday,
           ccy_id,
           code,
           version,
           seal,
           lst_upd_ts
    from   cut_calendar
    where  id != 1;
begin
  for calendar in cursorcutoffcalendar
  loop
    select coalesce (max (id), 1)
    into   v_sdcalendarid
    from   sd_calendar;

    v_sdcalendarid := v_sdcalendarid + 1;

    insert into sd_calendar (id,
                             name,
                             calendar_role_id,
                             description,
                             use_in_cutoff,
                             pty_id,
                             lock_code,
                             data_owner_id,
                             cnt_id,
                             non_business_days_monday,
                             non_business_days_tuesday,
                             non_business_days_wednesday,
                             non_business_days_thursday,
                             non_business_days_friday,
                             non_business_days_saturday,
                             non_business_days_sunday,
                             ccy_id,
                             code,
                             version,
                             seal,
                             lst_upd_ts)
    values      (v_sdcalendarid,
                 calendar.name,
                 calendar.calendartypid,
                 calendar.description,
                 calendar.use_in_cutoff,
                 calendar.ptyid,
                 calendar.lockcode,
                 calendar.dataownerid,
                 calendar.cntid,
                 calendar.nonbusinessdaysmonday,
                 calendar.nonbusinessdaystuesday,
                 calendar.nonbusinessdayswednesday,
                 calendar.nonbusinessdaysthursday,
                 calendar.nonbusinessdaysfriday,
                 calendar.nonbusinessdayssaturday,
                 calendar.nonbusinessdayssunday,
                 calendar.ccyid,
                 calendar.code,
                 calendar.version,
                 calendar.seal,
                 calendar.lstupdts);
  end loop;
end;
/

但是，我会强烈在这里推荐两件事：

使用序列生成 id 值
在单个插入语句中执行此操作，就像我在上面显示的那样。

如果出于某种原因（为什么不？）您不能使用序列，您仍然可以执行以下操作：

insert into sd_calendar (id,
                         name,
                         calendar_role_id,
                         description,
                         use_in_cutoff,
                         pty_id,
                         lock_code,
                         data_owner_id,
                         cnt_id,
                         non_business_days_monday,
                         non_business_days_tuesday,
                         non_business_days_wednesday,
                         non_business_days_thursday,
                         non_business_days_friday,
                         non_business_days_saturday,
                         non_business_days_sunday,
                         ccy_id,
                         code,
                         version,
                         seal,
                         lst_upd_ts)
  select (select coalesce (max (id), 1) from sd_calendar) + rownum id,
         name,
         calendar_typ_id,
         description,
         'Y',
         pty_id,
         lock_code,
         data_owner_id,
         cnt_id,
         non_business_days_monday,
         non_business_days_tuesday,
         non_business_days_wednesday,
         non_business_days_thursday,
         non_business_days_friday,
         non_business_days_saturday,
         non_business_days_sunday,
         ccy_id,
         code,
         version,
         seal,
         lst_upd_ts
  from   cut_calendar
  where  id != 1;

我推荐单 sql 语句方法的原因是它更易于维护（代码少得多！），更易于测试（您可以自行运行 SQL 语句以查看将插入哪些行）并且它'将比围绕光标的相应循环更快。这是因为关系数据库非常擅长处理大量数据 - 这是它们的设计目的。

但是，当您循环游标（并基于游标执行 DML）时，您正在做的是：

从 PL/SQL 引擎调用 SQL 引擎以获取行。
然后返回到 PL/SQL 引擎对结果进行处理。
然后返回 SQL 引擎运行 DML 语句。
然后返回到 PL/SQL 引擎获取下一行
重复步骤 2-4，直到找不到更多行。

这是非常多的上下文切换。为什么不通过使用单个 DML 语句批量处理整个数据集来完全避免这种情况。如果您愿意，您甚至可以将该语句嵌入到 PL/SQL 中！

【讨论】：

我又遇到了一个新问题，我已经更新了我的答案，你能再检查一次吗？
@Boerejef 来自我上面的回答：4. When you use a cursor for loop, you don't need to explicitly open or close the cursor.... 所以，删除关闭光标语句。出于好奇，为什么您仍然坚持使用 cursor-for-loop 方法而不是使用单个插入语句？