Reputation: 3184
Given the following tables:
Car
int id PK
int modelId FK
CarDetails
int carId PK, FK to Car.id
varchar(50) description
How would I indicate that the @Id
of CarDetails
is also a foreign key to Car
?
I've tried:
@Entity
public class Car {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
@ManyToOne
@JoinColumn(name = "modelId", nullable = false)
private Model model;
//setters & getters
}
@Entity
public class CarDetails {
@Id
@OneToOne
@JoinColumn(name = "carId", nullable = false)
private Car car;
private String description;
//setters & getters
}
However, I get the error
org.hibernate.MappingException: Composite-id class must implement Serializable: com.example.CarDetails
After implementing Serializable
I get This class [class com.example.CarDetails] does not define an IdClass
. But I still get the error after adding @IdClass(Car.class)
to the CarDetails
class.
UPDATE
The IdClass
error originates from Spring:
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'carDetailsRepository': Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: This class [class com.example.CarDetails] does not define an IdClass
Here's the CarDetailsRepository:
public interface CarDetailsRepository extends JpaRepository<CarDetails, Car> {
}
Here are the relevant parts of my gradle build file:
plugins {
id 'java'
id 'eclipse'
id 'maven-publish'
id 'io.spring.dependency-management' version '1.0.3.RELEASE'
}
repositories {
mavenCentral()
mavenLocal()
}
dependencies {
pmd group: 'org.hibernate', name: 'hibernate-tools', version: '5.2.3.Final'
pmd group: 'org.hibernate', name: 'hibernate-core', version: '5.2.10.Final'
pmd group: 'org.hibernate.common', name: 'hibernate-commons-annotations', version: '5.0.1.Final'
compile('org.springframework.boot:spring-boot-starter')
compile('org.springframework.boot:spring-boot-starter-data-jpa')
compile('org.hibernate:hibernate-validator:5.2.4.Final')
compile('org.hibernate:hibernate-envers:5.2.10.Final')
compile('org.hibernate:hibernate-core:5.2.10.Final')
compile('org.hibernate.common:hibernate-commons-annotations:5.0.1.Final')
runtime('net.sourceforge.jtds:jtds:1.3.1')
runtime('com.microsoft.sqlserver:sqljdbc:4.2')
runtime('javax.el:javax.el-api:2.2.4')
testCompile('org.springframework.boot:spring-boot-starter-test')
}
dependencyManagement {
imports { mavenBom('org.springframework.boot:spring-boot-dependencies:1.5.4.RELEASE') }
}
Upvotes: 7
Views: 2448
Reputation: 3276
You might try mapping CarDetails
like this:
@Entity
public class CarDetails {
@Id
private int id;
@MapsId
@OneToOne
@JoinColumn(name = "carId", nullable = false)
private Car car;
private String description;
//setters & getters
}
Note the @MapsId
annotation.
Upvotes: 2
Reputation: 5448
Probably the best way is to reference carId
twice in your CarDetails
entity--once for the @Id and once for the foreign key reference. You must declare one of these references with insertable=false
and updatable=false
so that JPA doesn't get confused trying to manage the same column in two spots:
@Entity
public class CarDetails {
@Id
@Column(name = "carId", insertable = false, updatable = false)
private int carId; // don't bother with getter/setter since the `car` reference handles everything
@OneToOne
@JoinColumn(name = "carId", nullable = false)
private Car car;
private String description;
//setters & getters
}
It looks odd, but it'll work and it's actually the (most) preferred method.
Upvotes: 5