Question

我们被要求创建一个数据库，然后是一个表，然后用givens填充它。这是我到目前为止所提出的：

sqlite3 me5.db;

create table petID(pet_id int(3) PRIMARY KEY, pet_name varchar(10), pet_type varchar(10), pet_age int(3));

INSERT INTO petID(pet_id, pet_name, pet_type, pet_age) VALUES(246, 'ROVER', 'DOG', 12);
INSERT INTO petID(pet_id, pet_name, pet_type, pet_age) VALUES(298, 'SPOT', 'DOG', 2);
INSERT INTO petID(pet_id, pet_name, pet_type, pet_age) VALUES(341, 'MORRIS', 'CAT', 4);
INSERT INTO petID(pet_id, pet_name, pet_type, pet_age) VALUES(519, 'TWEEDY', 'BIRD', 2);

create table petowner(pet_id int(3), owner varchar(100) PRIMARY KEY, FOREIGN KEY(pet_id) REFERENCES petID(pet_id) ON DELETE CASCADE);

INSERT INTO petowner(pet_id, owner) VALUES(246, 'SAM COOK');
INSERT INTO petowner(pet_id, owner) VALUES(298, 'TERRY KIM');

但是，当我在下面插入这两个时：

INSERT INTO petowner(pet_id, owner) VALUES(341, 'SAM COOK');
INSERT INTO petowner(pet_id, owner) VALUES(519, 'TERRY KIM');

我收到'约束失败'错误。任何想法如何解决这一问题？感谢

Answer 1

您违反的约束是petowner的主键;它会阻止'SAM COOK'出现两次。

如果宠物可以拥有多个所有者，那么petowner表的主键必须包含两个列：

CREATE TABLE petowner(
    pet_id int(3),
    owner varchar(100),
    PRIMARY KEY(pet_id, owner),
    FOREIGN KEY(pet_id) REFERENCES petID(pet_id) ON DELETE CASCADE
);

失败约束 - 如何在sqlite3表中正确插入内容？

1 个答案: