在Oracle SQL中檢查約束條件

Question

我有下表Goods_In_Wagon（Goods_ID，Wagon_ID，Total_Weight）。 我需要創建一些if語句檢查約束，它說

「如果WAGON_ID介於90和99之間，那麼Total_Weight必須大於10」。 「 AND 」如果WAGON_ID在100和110之間，那麼Total_Weight必須大於20.「 「 AND 」如果WAGON_ID在111和120之間，那麼Total_Weight必須大於30.「

在SQL甲骨文這是可能的，如果是我怎麼能實現它

Answer 1

使用超出線的約束：

CREATE TABLE Goods_In_Wagon (
    Goods_ID NUMBER(whatever), 
    Wagon_ID NUMBER(whatever), 
    Total_Weight NUMBER(whatever), 
    CONSTRAINT Check_WagID_Weight 
    CHECK (Wagon_ID NOT BETWEEN 90 AND 99 OR Total_Weight > 10) 
) 

如果Wagon_ID是90和99之間不 ，約束通過。如果它在90到99之間，那麼Total_Weight必須大於10.

這樣的一個外部約束允許您在行級應用約束邏輯，這意味着它可以使用任何列值。

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附錄下面是如何處理與Wagon_ID和Total_Weight範圍內更新的問題。可能有其他的方法，但這種感覺就像「最乾淨」，這意味着它是最簡單的對我個人閱讀:)

CREATE TABLE Goods_In_Wagon(
    Goods_ID NUMBER(whatever), 
    Wagon_ID NUMBER(whatever), 
    Total_Weight NUMBER(whatever), 
    CONSTRAINT Check_WagID_Weight 
    CHECK (
     (Wagon_ID < 90) OR 
     (Wagon_ID BETWEEN 90 AND 99 AND Total_Weight > 10) OR 
     (Wagon_ID BETWEEN 100 AND 110 AND Total_Weight > 20) OR 
     (Wagon_ID BETWEEN 111 AND 120 AND Total_Weight > 30) OR 
     (Wagon_ID > 120) 
    ) 
) 

Answer 2

修訂，以反映附加要求

CREATE TABLE Goods_In_Wagon 
(
    Goods_ID 
    ,Wagon_ID 
    ,Total_Weight 
    CONSTRAINT check_Weight 
    CHECK ( 
     WAGON_ID < 90 
     OR 
     (TOTAL_WEIGHT > 10 AND WAGON_ID >= 90 AND WAGON_ID <= 99) 
     OR 
     (TOTAL_WEIGHT > 20 AND WAGON_ID >= 100 AND WAGON_ID <= 110) 
     OR 
     (TOTAL_WEIGHT > 30 AND WAGON_ID >= 111 AND WAGON_ID <= 120) 
     OR 
     WAGON_ID > 120 
    ) 
)