SQL Server中的條件約束

Question

我在創建Microsoft SQL Server中的表創建中包含條件約束時遇到問題。我似乎無法弄清楚。

我試過case陳述，if then陳述，似乎沒有任何工作。

這是甚至可能的，因爲我不斷收到語法錯誤？

CREATE TABLE SECTION 
(
    c# int FOREIGN KEY REFERENCES Course(c#), 
    se# int, 
    emp# int FOREIGN KEY REFERENCES Professor(EMP#), 
    class_time time, 
    controlNumber int DEFAULT 20, 
    CONSTRAINT pk_SectionID PRIMARY KEY (c#, se#), 
    CONSTRAINT chk_controlNumber CHECK (controlNumber >= 40 AND controlNumber <=60), 

    CONSTRAINT chk_c# CHECK (when c# between 3000 and 5000 then controlNumber <=40) 
); 

謝謝。

Answer 1

您需要在兩次檢查，因爲否則他們是矛盾的結合，然後只是簡單的布爾邏輯組合它們：

CREATE TABLE SECTION(
    c# int FOREIGN KEY REFERENCES Course(c#), 
    se# int, 
    emp# int FOREIGN KEY REFERENCES Professor(EMP#), 
    class_time time, 
    controlNumber int DEFAULT 20, 
    CONSTRAINT pk_SectionID PRIMARY KEY (c#, se#), 
    CONSTRAINT chk_controlNumber CHECK (
     controlNumber between 40 AND 60 and (c# < 3000 or c# > 5000) or 
     (c# between 3000 and 5000 and controlNumber <= 40)) 
);