hibernate--Student_Course_Score设计-蒲公英云

hibernate--Student_Course_Score设计

红太狼 2024-02-18 15:00 151阅读 0赞

方式1、中间表Score使用联合主键，采用联合主键的方式稍微繁杂，这里不采用。

方式2、中间表Score不使用联合主键，即添加id作为主键。

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Student.java:

package com.bean;
import java.util.HashSet;
import java.util.Set;
import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinColumns;
import javax.persistence.JoinTable;
import javax.persistence.ManyToMany;
import javax.persistence.OneToMany;
@Entity
public class Student {
    private int id;
    private String name;
    private Set<Score> scores = new HashSet<Score>();
    private Set<Course> courses = new HashSet<Course>();
    @OneToMany(mappedBy="student",cascade=CascadeType.ALL,fetch=FetchType.EAGER)
    public Set<Score> getScores() {
        return scores;
    }
    public void setScores(Set<Score> scores) {
        this.scores = scores;
    }
    @ManyToMany(cascade=CascadeType.ALL,fetch=FetchType.EAGER)
    @JoinTable(name="score",
            joinColumns=@JoinColumn(name="student_id"),         
            inverseJoinColumns = @JoinColumn(name="course_id")
    )
    public Set<Course> getCourses() {
        return courses;
    }
    public void setCourses(Set<Course> courses) {
        this.courses = courses;
    }
    @Id
    @GeneratedValue
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
}

Score.java:

package com.bean;
import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Table;
@Entity
@Table(name="score")
public class Score {
    private int id;
    private int grade;
    private Student student;
    private Course course;
    @Id
    @GeneratedValue
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public int getGrade() {
        return grade;
    }
    public void setGrade(int grade) {
        this.grade = grade;
    }
    @ManyToOne(cascade=CascadeType.ALL)
    @JoinColumn(name="student_id")
    public Student getStudent() {
        return student;
    }
    public void setStudent(Student student) {
        this.student = student;
    }
    @ManyToOne(cascade=CascadeType.ALL)
    @JoinColumn(name="course_id")
    public Course getCourse() {
        return course;
    }
    public void setCourse(Course course) {
        this.course = course;
    }
}

Course.java:

package com.bean;
import java.util.HashSet;
import java.util.Set;
import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.ManyToMany;
@Entity
public class Course {
    private int id;
    private String name;
    @Id
    @GeneratedValue
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
}