5

I am using Spring JPA and Spring Data Rest with SpringBoot. I have a DB table called user and an entity for this table. I have no controller for this application.

@Entity
@Table(name = "USER")
public class User implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Basic(optional = false)
    @Column(name = "USER_ID")
    private Integer userid;

    @Basic(optional = false)
    @Column(name = "USER_NAME")
    private String username;
}

And now, I need to add one more field which isn't a column in the USER table. It will be used by some monitoring tool for tracing purpose. 

@Entity
@Table(name = "USER")
public class User implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Basic(optional = false)
    @Column(name = "USER_ID")
    private Integer userid;

    @Basic(optional = false)
    @Column(name = "USER_NAME")
    private String username;

    private String tracer;  // this field is not in DB
}

I am getting a jdbc.spi.SqlExceptionHelper - Invalid column name "tracer" after adding this field, which makes sense because this class is annotated as an entity. My question is that: is there a way to add a non-db field into an entity class? I guess not, but would like to know in case someone has a solution. Thanks.

jlp
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1 Answers1

18

Yes, just add the annotation @Transient to your field.

You can read more from the API docs:

https://docs.jboss.org/hibernate/jpa/2.1/api/javax/persistence/Transient.html

And here (section 37.1.2.1):

https://docs.oracle.com/javaee/7/tutorial/persistence-intro001.htm#BNBQA

Hope it helps.

Fabiano
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