Question

我有三个表格Issue，IssueReports和Location，结构如下。

问题和位置具有多对一关系。 Issue和IssueReports没有物理链接，但可以有一些共同的字段。

IssueReports
-------------
ID (Number); 
Issue_Number (Varchar); 
Issue_Loc_Name (Varchar)
and some other fields for the report....

Issue
-----------------
ID (Number);
IssueNumber (Varchar);
Issue_Loc_Id (Number)

Location
-----------------
ID (Number);
Loc_Name (Varchar)

我想更新Issue_Loc_Name多行中的IssueReports字段Loc_Name IssueNumber问题表和IssueNumber IssueReport表是平等的。

我已经编写了以下过程来根据上面给出的条件更新多个记录，但是我获得的是表Issue_Loc_name的多行IssueReport的相同值。

DECLARE
   IR_LOCNAME    VARCHAR2(10);
   IRNUM_TO_SEARCH VARCHAR2(10);
   ISNUM_TOSEARCH VARCHAR2(10);
   Cursor c1 is select ir.Issue_Number, is.IssueNumber, loc.loc_name
    from IssueReports ir, Issue is, Location loc
    where loc.id = is.Issue_Loc_Id
                AND ir.Issue_Number = is.IssueNumber;      
BEGIN
   OPEN c1;
   LOOP
      FETCH c1 INTO IRNUM_TO_SEARCH, ISNUM_TOSEARCH, IR_LOCNAME;
      DBMS_OUTPUT.put_line(IRNUM_TO_SEARCH || ' ' || ISNUM_TOSEARCH || ' ' || IR_LOCNAME);
      EXIT WHEN c1%NOTFOUND;
      UPDATE IssueReports SET Issue_Loc_Name = IR_LOCNAME;
             WHERE IRNUM_TO_SEARCH = ISNUM_TOSEARCH;
   END LOOP;
   CLOSE C1;
END;
/

我的光标有问题吗？我正在使用Oracle 11G。

最诚挚的问候， MouliPC。

Answer 1

我认为问题在于：

  UPDATE IssueReports SET Issue_Loc_Name = IR_LOCNAME;
         WHERE IRNUM_TO_SEARCH = ISNUM_TOSEARCH;

如果您的两个局部变量IRNUM_TO_SEARCH和ISNUM_TO_SEARCH恰好相同，则会更新整个表格。否则，不会更新任何行。

你或许打算写以下内容吗？

  UPDATE IssueReports SET Issue_Loc_Name = IR_LOCNAME;
         WHERE IssueNumber = ISNUM_TOSEARCH;

Answer 2

我可以使用MERGE通过以下查询完成更新。

MERGE INTO IssueReport IR using 
           (select ir.Issue_Number as irin, 
               is.IssueNumber as isin, 
               loc.loc_name as location 
            from IssueReports ir, 
                 Issue is, 
                 Location loc 
            where loc.id = is.Issue_Loc_Id AND ir.Issue_Number = is.IssueNumber) result 
       ON (is.issue_number = result.isin) 
WHEN MATCHED then update set Issue_Loc_Name = result.location;

SQL - 更新不在游标循环中工作

2 个答案: