1
我在我的數據庫中有3個表格:教授,學科和課程。 從教授和學科到課程,這是多對一的關係。 我試圖把外鍵,但它不起作用。在jpa中添加外鍵和複合主鍵?
課程類:
package com.licenta.ascourses.model;
import java.io.Serializable;
import javax.persistence.Embeddable;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
@Embeddable
public class CourseId implements Serializable{
@ManyToOne
@JoinColumn(name="IDDISCIPLINE")
private int idDiscipline;
@ManyToOne
@JoinColumn(name="IDPROFESSOR")
private int idProfessor;
private String courseNo;
public int getIdDiscipline() {
return idDiscipline;
}
public void setIdDiscipline(int idDiscipline) {
this.idDiscipline = idDiscipline;
}
public int getIdProfessor() {
return idProfessor;
}
public void setIdProfessor(int idProfessor) {
this.idProfessor = idProfessor;
}
public String getCourseNo() {
return courseNo;
}
public void setCourseNo(String courseNo) {
this.courseNo = courseNo;
}
public boolean equals(Object o) {
return true;
}
public int hashCode() {
return 1;
}
}
學科門類:
package com.licenta.ascourses.model;
import java.io.Serializable;
import java.util.HashSet;
import java.util.Set;
import javax.persistence.CascadeType;
import javax.persistence.ElementCollection;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.Id;
import javax.persistence.OneToMany;
import javax.persistence.Table;
@Entity
@Table(name="Disciplines")
public class Discipline implements Serializable {
private int idDiscipline;
@Id
private String name;
private String description;
private int an;
private int semestru;
public Discipline()
{
}
public Discipline(int idDiscipline, String name, String description, int an, int semestru) {
super();
this.idDiscipline = idDiscipline;
this.name = name;
this.description = description;
this.an = an;
this.semestru = semestru;
}
public Discipline(int idDiscipline, String name, String description, int an, int semestru, Set<Course> courses) {
super();
this.idDiscipline = idDiscipline;
this.name = name;
this.description = description;
this.an = an;
this.semestru = semestru;
}
public int getIdDiscipline() {
return idDiscipline;
}
public void setIdDiscipline(int idDiscipline) {
this.idDiscipline = idDiscipline;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
public int getAn() {
return an;
}
public void setAn(int an) {
this.an = an;
}
public int getSemestru() {
return semestru;
}
public void setSemestru(int semestru) {
this.semestru = semestru;
}
}
這是怎麼我的課程表在Hibernate
package com.licenta.ascourses.model;
import java.io.Serializable;
import javax.persistence.AssociationOverride;
import javax.persistence.AssociationOverrides;
import javax.persistence.EmbeddedId;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinColumns;
import javax.persistence.ManyToOne;
import javax.persistence.Table;
@Entity
@Table(name="Courses")
@AssociationOverrides({
@AssociationOverride(name = "pk.discipline",
joinColumns = @JoinColumn(name = "IDDISCIPLINE")),
@AssociationOverride(name = "pk.professor",
joinColumns = @JoinColumn(name = "IDPROFESSOR")) })
public class Course implements Serializable {
private CourseId idCourse=new CourseId();
private int year;
private int semester;
public Course()
{
}
public Course(CourseId idCourse, int idDiscipline, int idProfessor,int year, int semester) {
super();
this.idCourse = idCourse;
this.year = year;
this.semester = semester;
}
@EmbeddedId
public CourseId getIdCourse() {
return idCourse;
}
public void setIdCourse(CourseId idCourse) {
this.idCourse = idCourse;
}
public int getYear() {
return year;
}
public void setYear(int year) {
this.year = year;
}
public int getSemester() {
return semester;
}
public void setSemester(int semester) {
this.semester = semester;
}
}
複合主鍵CourseId類:
create table Courses (
courseNo varchar2(255 char) not null,
idDiscipline number(10,0) not null,
idProfessor number(10,0) not null,
semester number(10,0) not null,
year number(10,0) not null,
primary key (courseNo, idDiscipline, idProfessor)
)
因此,外鍵不會出現。請幫我
哪裏是另一個表?我認爲你需要申報課程和課程教授課程。 – msagala25
@msagala編輯,尋找紀律類 –