In my program I realize a problem when it get a inheritance and a oneToMany relationship. That is:
I put to run. It will create the tables, without the foreign key. But when I remove the Inheritance annotations, and run again. It creates as foreign.
Class Employer
package com.example.TablePerConcreteClassExample.model;
import java.util.List;
import javax.persistence.Column;
import javax.persistence.DiscriminatorColumn;
import javax.persistence.DiscriminatorValue;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Inheritance;
import javax.persistence.InheritanceType;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.OneToMany;
import javax.persistence.Table;
@Entity
@Table(name="Employer")
@Inheritance(strategy=InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(name="type")
@DiscriminatorValue(value="Employer")
public class Employer {
@Id
@Column (name = "empNo", nullable=false)
@GeneratedValue(strategy = GenerationType.AUTO)
private int empNo;
@Column(name = "name", nullable=false)
private String name;
@OneToMany (mappedBy = "employer",
fetch=FetchType.LAZY)
private List<Vehicle> vehicles;
public int getEmpNo() {
return empNo;
}
public void setEmpNo(int empNo) {
this.empNo = empNo;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public List<Vehicle> getVehicles() {
return vehicles;
}
public void setVehicles(List<Vehicle> vehicles) {
this.vehicles = vehicles;
}
}
And Class Vehicle
package com.example.TablePerConcreteClassExample.model;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Table;
@Entity
@Table(name="Vehicle")
public class Vehicle {
@Id
@Column (name = "id", nullable=false)
@GeneratedValue(strategy = GenerationType.AUTO)
private int id;
@Column(name = "name", nullable=false)
private String name;
@ManyToOne(fetch = FetchType.EAGER)
@JoinColumn(name = "empNo", nullable=false)
private Employer employer;
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;
}
public Employer getEmployer() {
return employer;
}
public void setEmployer(Employer employer) {
this.employer = employer;
}
}
And my application.properties:
spring.datasource.url=jdbc:mysql://localhost:3306/TablePerConcreteClass?createDatabaseIfNotExist=true&useSSL=false&useTimezone=true&serverTimezone=UTC
spring.datasource.username=root
spring.datasource.password=
spring.jpa.database=MYSQL
spring.datasource.platform=mysql
spring.jpa.properties.hibernate.jdbc.lob.non_contextual_creation=true
spring.database.driverClassName=com.mysql.cj.jdbc.Driver
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5InnoDBDialect
spring.jpa.hibernate.ddl-auto=create-drop
spring.jpa.show-sql=true
spring.servlet.multipart.enabled=true
I expected a inheritance and in the vehicle table a Employer’s foreign key.
The actual results are the inheritance, but no foreign key. But when I remove inheritance annotations, the foreing key will be created.
