[英]Insert Into mysql using spring boot Jpa not working
I am trying to persist data into a Mysql db using JpaRepository in spring boot however I keep getting the following error, not sure what am doing wrong:我试图在 Spring Boot 中使用 JpaRepository 将数据保存到 Mysql 数据库中,但是我不断收到以下错误,不知道做错了什么:
java.sql.SQLIntegrityConstraintViolationException: Cannot add or update a child row: a foreign key constraint fails
My Model classes looks like:我的模型类看起来像:
@Entity
@Table(name = "cart")
public class Cart {
@Id
@Column(name = "id", unique = true, nullable = false)
private String id;
@Column(name = "user_id")
private int userId;
@OneToMany(fetch = FetchType.LAZY, targetEntity = User.class)
@JoinColumn(name="user_id", referencedColumnName = "id", insertable = false, updatable = false)
private List<User> user;
public List<User> getUser() {
return user;
}
public void setUser(List<User> user) {
this.user = user;
}
public Cart() {
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public int getUserId() {
return userId;
}
public void setUserId(int userId) {
this.userId = userId;
}
}
@Entity
@Table(name = "user")
public class User {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "id", unique = true, nullable = false, columnDefinition = "integer")
private Integer id;
@Column(name = "name")
private String name;
@Column(name = "email")
private String email;
@Column(name = "phone")
private String phone;
public User() {
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public String getPhone() {
return phone;
}
public void setPhone(String phone) {
this.phone = phone;
}
}
My repository:我的存储库:
@Repository
public interface CartRepository extends JpaRepository<Cart, String> {
}
What am i doing wrong and is there a better way to persist data?我做错了什么,有没有更好的方法来保存数据?
Update: This is the data am using on postman:更新:这是邮递员使用的数据:
{
"id": "5beeb524-20fc-11ea-978f-2e728ce88125",
"user_id": 1
}
However when i log the above data, it returns the id as above but the user_id always returns 0但是,当我记录上述数据时,它返回上述 id 但 user_id 始终返回 0
The id for cart is not auto-generated.购物车的 ID 不是自动生成的。
Add a generator for the unique id.为唯一 id 添加一个生成器。 For example, for a string the generator could be like :
例如,对于一个字符串,生成器可能是这样的:
@Id
@GeneratedValue(generator = "uuid")
@Column(name = "id", unique = true, nullable = false)
private String id;
Find a suitable type and generator for your unique id accordingly.相应地为您的唯一 ID 找到合适的类型和生成器。 I hope it helps.
我希望它有帮助。
EDIT: After seeing the stack trace, this also look somewhat helpful : could not execute statement SQL constraint [id] nested exception is org.hibernate.exception.ConstraintViolationException编辑:在看到堆栈跟踪后,这看起来也有些帮助: 无法执行语句 SQL 约束 [id] 嵌套异常是 org.hibernate.exception.ConstraintViolationException
Also the issue seems to because the cart.user_id is a foreign key referencing the user.id in user class which is violating some constraints.此外,问题似乎是因为 cart.user_id 是引用 user.id 的外键,它违反了一些约束。
Add the following to user model class :将以下内容添加到用户模型类:
@OneToMany(mappedBy = "user_id", cascade = CascadeType.ALL)
private List<User> users;
And add the following to cart model class :并将以下内容添加到购物车模型类:
@ManyToOne
@JoinColumn
private int user_id;
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