如何在 Spring Boot 中与 JPA 和 Hibernate 建立课程、学生、进度关系？

Question

我正在尝试在 Spring Boot 中实现 Student、Course 和 Progress 关系。我在课程中有一组学生注册了该课程。我想跟踪每个学生的进度。我的实体是。

课程

@Entity
@Table(name = "Course")
public class Course {

@Id
@GeneratedValue(strategy = GenerationType.SEQUENCE)
@Column(name = "id")
private int courseId;

@Column(name = "name")
private String courseName;

@ManyToMany(fetch = FetchType.LAZY,
            cascade = {
                CascadeType.PERSIST,
                CascadeType.MERGE
            })
    @JoinTable(name = "UserCourse",
            joinColumns = { @JoinColumn(name = "user") },
            inverseJoinColumns = { @JoinColumn(name = "course") })
private Set<UserInfo> users = new HashSet<>();
}

用户信息

@Entity
@Table(name = "UserInfo")
public class UserInfo {

@Id
@GeneratedValue(strategy = GenerationType.SEQUENCE)
@Column(name = "id")
private Integer userId;

@Column(name = "fname")
private String firstName;

@Column(name = "lname")
private String lastName;

@Column(name = "email")
private String userEmail;
}

我如何跟踪每个选择该课程的用户的进度。它应该是一个浮点值。

Answer 1

通过将进度列映射到实体，将进度列添加到 UserCourse 表中。参见方法：

https://vladmihalcea.com/the-best-way-to-map-a-many-to-many-association-with-extra-columns-when-using-jpa-and-hibernate/