Oracle触发器使用case语句创建

Posted 2021-04-26

我在oracle中创建触发器时遇到问题，我有一个表“ stock”。我有字段“ xxx”，“ yyy”和“ zzz”。我想创建一个触发器，可以在插入或更新后立即填充此“股票”表上的另一个字段。我已经有点累了，但是我不能。

 create or replace 
Trigger Connector_Stock_Trg 
AFTER INSERT OR UPDATE OF xxx,yyy,zzz ON STOCK
For Each Row 
Declare 
L_Temp VARCHAR2(64);
BEGIN
L_Temp := Case  
         When Xxx Is Not Null Then Xxx
         When yyy Is Not Null And zzz Is Not Null Then yyy||'_'||zzz
         When Yyy Is Null And zzz Is Not Null Then zzz
         WHEN zzz IS NULL AND yyy IS NOT NULL THEN yyy
   END;

   Update Stock 
   SET CONNECTOR=L_Temp;
END;

答案

您不必更新表STOCK，而只需按以下方式向:NEW.CONNECTOR分配一个表达式。

CREATE OR REPLACE TRIGGER CONNECTOR_STOCK_TRG AFTER
    INSERT OR UPDATE OF XXX, YYY, ZZZ ON STOCK
    FOR EACH ROW
--DECLARE
--    L_TEMP   VARCHAR2(64);
BEGIN
    :NEW.CONNECTOR := -- USE :NEW
        CASE
            WHEN XXX IS NOT NULL THEN XXX
            WHEN YYY IS NOT NULL AND ZZZ IS NOT NULL THEN YYY
                                                          || '_'
                                                          || ZZZ
            WHEN YYY IS NULL AND ZZZ IS NOT NULL THEN ZZZ
            WHEN ZZZ IS NULL AND YYY IS NOT NULL THEN YYY
        END;

--    UPDATE STOCK
--    SET
--        CONNECTOR = L_TEMP;

END;
/

干杯！