TransientObjectException

Entity
@Table(name = "ADDRESS")
public class Address {

    @Id
    @Column(name = "ID")
    @GeneratedValue
    private int addressid;

  开发者_运维技巧  @OneToOne
    @JoinColumn(name = "CITY_ID",nullable = true,insertable=false, updatable=false)
    private City city = new City();

    @OneToOne
    @JoinColumn(name = "DISTRICT_ID",nullable = true,insertable=false, updatable=false)
    private District district = new District();
}

Hi there, I have a class called Address and I cannot save this class in hibernate with DISTRICT_ID = null.

The error is

org.hibernate.TransientObjectException: object references an unsaved transient instance - save the transient instance before flushing: form.District

I just don't know what I am missing....

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If you want district to be null, it should be actually null rather than pointing to the new transient instance:

@OneToOne
@JoinColumn(name = "DISTRICT_ID",nullable = true,insertable=false, updatable=false)     
private District district = null;

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Maybe you should consider having city_id and city_name in the same object and if you want the City and District table to be read only then you don't your city and district to be persisted.

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Is District annotated with @Entity?
You probably need to specify cascade on @OneToOne Example: @OneToOne(cascade={CascadeType.PERSIST})

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If you want to save District with null DISTRICT_ID you can't use it as primary key and consequently you can't annotate it with @Id. You will have to choose different id for the District entity.