Hana Studio(SQL脚本)触发器上的条件更新 [英] Conditional update on Hana Studio (SQL Script) trigger

问题描述

我有两个示例表:

    TABLE1:
      ID    | COLUMN_B| COLUMN_C
   _________|_________|_________
       1    |    0    |    1
    ________|_________|_________
       2    |    0    |    1
    ________|_________|_________
       3    |    0    |    1


    TABLE2:
      ID    | COLUMN_E| COLUMN_F
    ________|_________|________
       1    |    Y    |    X
    ________|_________|_________
       2    |    Y    |    X
    ________|_________|_________
       3    |    Y    |    X

我想做的是，当表1中的B列更新为特定值(例如100)时，使用SQL脚本在Hana Studio上编写触发器以更新表2中的E列. 表1中的行在表2中带有第一列(ID)引用.

What I would like to do is to write a trigger on Hana Studio using SQL Script to update column E from table 2 when column B from table 1 is updated to a specific value (let's say, 100). Rows from table 1 are referenced in table 2 with the first column (ID).

我编写了以下代码:

create trigger "UPDATE_TABLES"
    after update of "COLUMN_B" on "TABLE1"
    referencing new row as new, old row as old
    for each row 
begin
    update "TABLE2"
    set "COLUMN_E" = 'my new value'
    where :old."COLUMN_B" = '100' and "TABLE1"."ID" = :old."ID";
end;

当我将第1行的TABLE1.COLUMN_B设置为100时，我希望代码将第1行的TABLE2.COLUMN_E更改为我的新值"，但是什么也没有发生.有人可以指出我在这到底在做什么错吗?

When I set TABLE1.COLUMN_B on row 1 to 100, I expect the code to change TABLE2.COLUMN_E to "my new value" on row 1, but nothing happens. Could anyone point what exactly I am doing wrong here?

推荐答案

我认为触发代码中的UPDATE语句应该稍有不同，如下所示

I guess the UPDATE statement in the trigger code should be slighly different as follows

create trigger "UPDATE_TABLES"
    after update of "COLUMN_B" on "TABLE1"
    referencing new row as new, old row as old
    for each row 
begin
    update "TABLE2"
    set "COLUMN_E" = 'my new value'
    where :new."COLUMN_B" = '100' 
    and TABLE2.ID = :old."ID";
end;

否则，在创建触发器时出现语法错误 您能验证一下吗?

Otherwise, I get syntax error while creating the trigger Could you please verify?

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