java.sql.SQLException：字段“id”没有默认值

Question

我正在尝试将数据插入到arrivaltimes时间表中，但出现以下错误：

java.sql.SQLException：字段“id”没有默认值

stt.execute("CREATE TABLE IF NOT EXISTS stops"
            + "(stop_id INT(11) NOT NULL AUTO_INCREMENT PRIMARY KEY, "
            + " name varchar(30) NOT NULL, "
            + " route INT(11) NOT NULL, "
            + " lat double(10,6) NOT NULL, "
            + " longi double(10,6)NOT NULL) " );

    stt.execute("INSERT INTO stops(name, route, lat, longi) values"
            + "('blabla', '1', '93.838039', '15.700440' ),"
            + "('backery', '9', '98.868863', '19.665438' )" );

    stt.execute("CREATE TABLE IF NOT EXISTS arrivaltimes(id INT(11) NOT NULL PRIMARY KEY,"
            +  " weekday VARCHAR(20) NOT NULL,"
            + "arrivaltime time NOT NULL,"
            + " stop_id INT, FOREIGN KEY fk_stop_id(stop_id) REFERENCES stops(stop_id) )" );
    //The error appears in this execution statement.
    stt.execute("INSERT INTO arrivaltimes(weekday, arrivaltime) values"
            + "('mon-fri', '05:30' ),"
            + "('mon-fri', '06:07' )" );

Answer 1

您在到达时间表中缺少主键的AUTO INCREMENT 。 只需要在创建表时添加AUTO_INCREMENT

stt.execute("CREATE TABLE IF NOT EXISTS arrivaltimes(id INT(11) NOT NULL  AUTO_INCREMENT PRIMARY KEY,"
            +  " weekday VARCHAR(20) NOT NULL,"
            + "arrivaltime time NOT NULL,"
            + " stop_id INT, FOREIGN KEY fk_stop_id(stop_id) REFERENCES stops(stop_id) )" );

Answer 2

因为列id被定义为NOT NULL ，这意味着它必须有一个值，而您没有提供一个值。

Answer 3

我在 MySQL WorkBench 中的表遇到了同样的问题。 很明显，自动增量命令给字段“id”一个默认值。 这是适用于我的表的代码：

create table product( <br>
id int auto_increment PRIMARY KEY, <br>
name varchar(20), <br>
description varchar(100), <br>
price decimal(8,3) <br>
);