无法更新oracle sql表

Posted 2023-05-09

【中文标题】无法更新oracle sql表

【英文标题】：cannot update oracle sql table

【发布时间】：2020-11-26 21:43:40

【问题描述】：

有这个代码：

select clientinfo.client_surname, mi.medicine_price from clientinfo 
    join orderinfo oi on oi.client_id = clientinfo.client_id
    join ordered_medicines om on om.order_id = oi.order_id
    join medicine_instances mi on om.medicine_id_instance = mi.medicine_id_instance
    where add_months(birthdate, 65*12) < CURRENT_DATE and mi.medicine_price in (select max(medicine_price) from medicine_instances);
update
(select mi.medicine_price
from clientinfo 
    join orderinfo oi on oi.client_id = clientinfo.client_id
    join ordered_medicines om on om.order_id = oi.order_id
    join medicine_instances mi on om.medicine_id_instance = mi.medicine_id_instance
    where add_months(birthdate, 65*12) < CURRENT_DATE and mi.medicine_price in (select max(medicine_price) from medicine_instances)
    ) T
    set T.medicine_price = T.medicine_price * 0.98;

但是当我尝试运行它时出现错误： ORA-01779: 无法修改映射到非键保留表的列

我用谷歌搜索，但不明白如何解决它。有什么问题？

【问题讨论】：

我假设你的几个连接是“正确的类型”——你有连续的查找，并且在每种情况下你都连接到一个查找表，其中连接列是主键。唉，除非您通过约束或索引明确告诉 Oracle，某些列是“主键”或“唯一”，否则 Oracle 不会知道这一点，它会假设至少 可能歧义。如果我的假设是正确的，解决此问题的正确 方法是显式声明主键（或唯一键）约束。那么update 应该可以像写的那样工作。

【参考方案1】：

您可以按如下方式使用关联：

Update medicine_instances trg
  Set trg.medicine_price =
(select mi.medicine_price
  from   clientinfo 
         join orderinfo oi on oi.client_id = clientinfo.client_id
         join ordered_medicines om on om.order_id = oi.order_id
         join medicine_instances mi on om.medicine_id_instance = mi.medicine_id_instance
   where add_months(birthdate, 65*12) < CURRENT_DATE
     and mi.medicine_price in (select max(medicine_price) from medicine_instances)
     And mi.medicine_id_instance = trg.medicine_id_instance )
   Where exists
 (select 1
  from   clientinfo 
         join orderinfo oi on oi.client_id = clientinfo.client_id
         join ordered_medicines om on om.order_id = oi.order_id
         join medicine_instances mi on om.medicine_id_instance = mi.medicine_id_instance
   where add_months(birthdate, 65*12) < CURRENT_DATE
     and mi.medicine_price in (select max(medicine_price) from medicine_instances)
     And mi.medicine_id_instance = trg.medicine_id_instance )

【参考方案2】：

您应该能够将查询放入MERGE 语句（与ROWID 伪列相关）：

MERGE INTO medicine_instances dst
USING (
  select mi.ROWID AS rid
  from   clientinfo 
         join orderinfo oi
         on oi.client_id = clientinfo.client_id
         join ordered_medicines om
         on om.order_id = oi.order_id
         join medicine_instances mi
         on om.medicine_id_instance = mi.medicine_id_instance
  where  add_months(birthdate, 65*12) < CURRENT_DATE
  and    mi.medicine_price in (select max(medicine_price) from medicine_instances)
) src
ON ( src.rid = dst.ROWID )
WHEN MATCHED THEN
  UPDATE SET medicine_price = src.medicine_price * 0.98;