Question

Hi All

We generally put 4 field in every table named as CREATED_BY , LAST_UPDATED_BY , CREATION_DATE, LAST_UPDATED_DATE , So i thought why not put this in single class BaseDo and than inherit this into the class like EmployeeDo. The problem is if i annotate this BaseDo with @Entity i have to put one @Id field which i do not want . Is there a way to achieve this ?

@Entity
@Inheritance(strategy=InheritanceType.TABLE_PER_CLASS)
public class BaseDo implements Serializable {
    private static final long serialVersionUID = 6685603264139140757L;
    @Column(name="CREATED_BY" , nullable =false )
    private String createdBy;
    @Column(name="LAST_UPDATED_BY", nullable =false )
    private String lastUpdatedBy;
    @Column(name="CREATION_DATE", nullable =false )
    private Date creationDate;
    @Column(name="LAST_UPDATED_DATE", nullable =false )
    private Date lastUpdationDate;
}

---

@Entity
@Table(name="EMPLOYEE")
public class EmployeeDo extends BaseDo implements Serializable {

    private static final long serialVersionUID = 4465521188079217243L;
    @Id
    @Column(name="EMPLOYEE_ID" )
    private String employeeId ;
}

Thanks A Lot

Answer 1

you should use @MappedSuperclass

Please check it

http://docs.oracle.com/javaee/5/api/javax/persistence/MappedSuperclass.html