表錯誤：1452無法添加或更新子行：外鍵？

Question

我收到一個我完全不理解的錯誤。我想創建一個表，這裏是代碼：

create table matricula.curso_estudiantes 
(codigo varchar(8) NOT NULL, 
studentid varchar(8) NOT NULL, 
grade varchar(1) NOT NULL, 
term numeric(5) NOT NULL, 

PRIMARY KEY (codigo, studentid, term), 
    FOREIGN KEY (codigo) 
      REFERENCES curso(codigo), 
     FOREIGN KEY (studentid) 
      REFERENCES estudiantes(studentid)); 

insert into matricula.curso_estudiantes values 
("COMP2120","X00101010","C",201010), 
("COMP2315","X00101010","B",201030), 
("COMP2120","X00121111","B",201030), 
("COMP2315","X00121111","A",201030), 
("COMP2120","X00121234","A",201130), 
("COMP2900","X00101010","C",201110), 
("COMP3850","X00101010","B",201110), 
("COMP2900","X00121111","B",201130), 
("COMP3850","X00121111","A",201130), 
("COMP2315","X00121234","A",201130), 
("COMP2400","X00101010","C",201210), 
("MATH1500","X00101010","B",201210), 
("COMP2400","X00121111","B",2), 
("MATH1500","X00121111","A",2), 
("COMP3850","X00121234","A",2), 
("MATH1500","X00121234","W",2); 

但我得到這個錯誤，而不是：

Error Code: constraint fails (matricula . curso_estudiantes , CONSTRAINT curso_estudiantes_ibfk_2 FOREIGN KEY (studentid) REFERENCES estudiantes (studentid))

出了什麼問題？它創建表，但它給了我這個問題，沒有記錄插入到表中。哪個查詢解決了這個問題？我是mySQL的新手，所以我使用了很多教授的參考和例子。提前致謝。

Answer 1

您是否在estudiantes表中有正確的相應記錄？

A FOREIGN KEY表示您需要參考表中的數據，否則INSERT將不起作用。

要解決該問題，請首先使用有效數據創建並填充您的estudiantes和curso表。