2014-11-21 67 views
1

我有一些麻煩與MySQL的管理工作室,這是給我的錯誤有兩個外鍵約束引用同一個主鍵,都使用ON UPDATE CASCADE

Msg 1785, Level 16, State 0, Line 65 
Introducing FOREIGN KEY constraint 'FK__Likes__LikeeId__5A846E65' on table 'Likes' may cause cycles or multiple cascade paths. Specify ON DELETE NO ACTION or ON UPDATE NO ACTION, or modify other FOREIGN KEY constraints. 
Msg 1750, Level 16, State 0, Line 65 
Could not create constraint or index. See previous errors. 

這是關係到喜歡錶的代碼,配置文件表是我們從中獲得外鍵的地方。問題在於它說我不能同時擁有外鍵約束,因爲它創建了一個循環,但我不明白爲什麼會這樣。

CREATE TABLE Profile (
ProfileId VARCHAR(24), 
OwnerSSN VARCHAR(11) NOT NULL, 
Age INTEGER NOT NULL, 
AgeRangeStart INTEGER NOT NULL, 
AgeRangeEnd INTEGER NOT NULL, 
GeoRange INTEGER NOT NULL, 
Gender VARCHAR(1) NOT NULL, 
Hobbies VARCHAR(50), 
Height DECIMAL(2,1) NOT NULL, 
Weight INTEGER NOT NULL, 
HairColor VARCHAR(20), 
ProfileCreationDate DATETIME NOT NULL, 
ProfileModDate DATETIME NOT NULL, 
Active BIT NOT NULL, 
PRIMARY KEY(ProfileId), 
FOREIGN KEY (OwnerSSN) REFERENCES Customer(SSN), 
CHECK(Age < 120 AND Age >= 17), 
CHECK(AgeRangeStart >= 17 AND AgeRangeEnd >= AgeRangeStart), 
CHECK(GeoRange > 0)); 

CREATE TABLE Likes (
LikerId VARCHAR(24), 
LikeeId VARCHAR(24), 
Date_Time DATETIME , 
PRIMARY KEY (LikeeId, LikerId, Date_Time) , 
FOREIGN KEY(LikerId) REFERENCES Profile(ProfileId) 
ON UPDATE CASCADE, 
FOREIGN KEY(LikeeId) REFERENCES Profile(ProfileId) 
ON UPDATE CASCADE 
); 
+0

順便說一句'的CHECK子句是解析但http://dev.mysql.com/doc/refman/5.7/en/create-table.html所有存儲engines.'忽略 – bodo 2016-10-20 11:45:48

回答

1

這是當你需要開始使用觸發器。

CREATE TRIGGER tr_UpdateLikee BEFORE UPDATE 
ON Profile FOR EACH ROW 
UPDATE Likes 
SET likeeId = NEW.ProfileId 
Where LikeeId = Profile.ProfileId 

CREATE TRIGGER tr_UpdateLiker BEFORE UPDATE 
ON Profile FOR EACH ROW 
UPDATE Likes 
SET likerId = NEW.ProfileId 
Where LikerId = Profile.ProfileId