hibernate - Hibernate Inheritance - Referencing an entity annotated with @MappedSuperclass

Question

@MappedSuperclass
public abstract class AbstractBaseModel{ }

@MappedSuperclass
public class Person extends AbstractBaseModel { }

@Entity
public class APerson extends Person { }

@Entity
public class BPerson extends Person { }

@Entity
public class Course extends AbstractBaseModel { 
  @ManyToOne
  @JoinColumn(name ="person")
  private Person person;
}

Above structure will give an exception:

Caused by: org.hibernate.AnnotationException: @OneToOne or @ManyToOne on    
Course references an unknown entity: Person

It says you cannot use Person in mappings because it is not a concrete Entity. How do I achieve such an inheritance scenario?

Answer 1

简单，您将@MappedSuperclass注释更改Person为@Entity

@MappedSuperclass仅在您明确不希望类可查询或属于关系的一部分时使用。@Entity其他地方。

一个很好的启发式决定是看看你的超类是否abstract——如果是的话——使用@MappedSuperclass，就像你在AbstractBaseModel

Answer 2

@Entity
@Table(name="PERSON")
@Inheritance(strategy=InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(name="discriminator",discriminatorType=DiscriminatorType.STRING)
public absract class Person extends AbstractBaseModel { }

@Entity
public class APerson extends Person { }

@Entity
public class BPerson extends Person { }

@Entity
public class Course extends AbstractBaseModel { 
  @ManyToOne
  @JoinColumn(name ="person", **insertable = false, updatable = false** )
  private Person person;
}