sql - 外主键插入(增量问题)

Question

CREATE TABLE Accounts
(ID INTEGER IDENTITY(1,1) PRIMARY KEY);


CREATE TABLE Students
( ID INTEGER PRIMARY KEY , s_name VARCHAR(20) ,date_birth DATEtime,age AS (YEAR(CURRENT_TIMESTAMP) - YEAR(date_birth)) , school_id INTEGER ,
FOREIGN KEY(ID) REFERENCES Accounts(ID) ,
FOREIGN KEY(school_id) REFERENCES Schools(ID)
 );

当我插入学生时:

INSERT INTO Students (s_name , date_birth , school_id )
VALUES ( 'nada' , 2/2/1993 , 1)

发生错误: 无法将 NULL 值插入表“myschool.dbo.Students”的“ID”列；列不允许为空。插入失败。

Answer 1

您没有为 Students.ID 列指定值。您可能希望将其设置为身份，与您为 Account.ID 列所做的操作相同:

ID INT IDENTITY (1,1) PRIMARY KEY