[TOC] 建立測試表 查看版本信息 ~~~ select version(); 5.7.22 ~~~ 創建父表 ~~~ drop table if exists Models; CREATE TABLE Models ( ModelID SMALLINT UNSIGNED NOT NULL AUTO_INCREMENT, Name VARCHAR(40) NOT NULL, PRIMARY KEY (ModelID) ); ~~~ 創建子表 ~~~ drop table if exists Orders; CREATE TABLE Orders ( ID SMALLINT UNSIGNED NOT NULL PRIMARY KEY, ModelID SMALLINT UNSIGNED NOT NULL, Description VARCHAR(40), FOREIGN KEY (ModelID) REFERENCES Models (ModelID) ON DELETE cascade ); ~~~ 測試 測試用例-無父表相應數據，先插入子表 `insert into Orders(Id,ModelID,Description) values (1,1,'a');` 結果：執行失敗 `異常：[2018-07-31 11:08:01] 23000 Cannot add or update a child row: a foreign key constraint fails (bov.Orders, CONSTRAINT Orders_ibfk_1 FOREIGN KEY (ModelID) REFERENCES Models (ModelID) ON DELETE CASCADE)` 原因：通不過on delete cascade 的外鍵約束檢查 測試用例-先插入主表數據，再插入子表數據 ~~~ insert into Models(ModelID,Name) values (1,'a'); insert into Orders(Id,ModelID,Description) values (1,1,'a'); ~~~ 結果：執行成功 ~~~ select * from Models; 1 a select * from Orders; 1 1 a ~~~ 測試用例-父子表都有數據，刪除子表數據 ~~~ delete from Orders where id = 1; ~~~ 結果：執行成功 ~~~ select * from Models; 1 a select * from Orders; 為空 ~~~ 測試用例-父子表都有數據，刪除父表書庫 ~~~ delete from Models where ModelID = 1; ~~~ 結果：執行成功 ~~~ select * from Models; 為空 select * from Orders; 為空 ~~~ 測試用例-父子表都有數據，更新子表外鍵 ~~~ update Orders set ModelID = 3 where ID =1; ~~~ 結果：執行失敗 `異常：[2018-07-31 12:33:02] 23000 Cannot add or update a child row: a foreign key constraint fails (bov.Orders, CONSTRAINT Orders_ibfk_1 FOREIGN KEY (ModelID) REFERENCES Models (ModelID) ON DELETE CASCADE)` 原因：通不過on delete cascade 的外鍵約束檢查 測試用例-父子表都有數據，更新父表主鍵 ~~~ update Models set ModelID = 2 where ModelID =1; ~~~ 結果：執行失敗 `異常：[2018-07-31 12:34:24] 23000 Cannot delete or update a parent row: a foreign key constraint fails (bov.Orders, CONSTRAINT Orders_ibfk_1 FOREIGN KEY (ModelID) REFERENCES Models (ModelID) ON DELETE CASCADE)` 原因：通不過on delete cascade 的外鍵約束檢查 測試用例-父子表都有數據，更新子表非外鍵 `update Orders set Description = 'b' where ID =1;` 結果：執行成功 ~~~ select * from Orders; 1 1 b ~~~ 測試用例-父子表都有數據，更新父表非主鍵 `update Models set Name = 'c' where ModelID =1;` 結果：執行成功 ~~~ select * from Models; 1 c ~~~