Inheritance mix in Hibernate 3.2.0 CR1 (annotations)

cd19D3cea · **Joined:** Mon Mar 13, 2006 3:12 pm **Posts:** 2

Hi,

I need help with Hibernate 3.2. CR1 and I hope that you can help me.
I need to implement following inheritance tree using Hibernate annotation:

Code:

(1) PersistentData::PeriodDependentMasterData::NetRegion 
(2) PersistentData::PeriodDependentMasterData::Carrier::ExternalCarrier 
(3) PersistentData::PeriodDependentMasterData::Carrier::UICCarrier

For (1) inheritance leg I'm using the InheritanceType.JOINED strategy.
For the legs (2) and (3), starting from Carrier class, I like to use the
InheritanceType.SINGLE_TABLE strategy. See following section:

Code:

@MappedSuperclass
abstract class PersistentData implements Serializable {
}

@Entity
@Table(name="PERIODDEPENDENDMASTERDATA")
@Inheritance(strategy=InheritanceType.JOINED)
abstract class PeriodDependentMasterData extends PersistentData {
}

@Entity
@Table(name="NETREGION")
@PrimaryKeyJoinColumn(name="ID")
public class NetRegion extends PeriodDependentMasterData {
}

@Entity
@Table(name="CARRIER")
@Inheritance(strategy=InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(name="MAPPINGTYPE_ID",discriminatorType=DiscriminatorType.INTEGER)
@DiscriminatorValue("10")
public abstract class Carrier extends PeriodDependentMasterData {
}

@Entity
@DiscriminatorValue("11")
public class ExternalCarrier extends Carrier {
}

@Entity
@DiscriminatorValue("13")
public class UICCarrier extends Carrier {
}

Because this code doesn't work for me I like to ask you following questions:

http://www.hibernate.org/hib_docs/v3/re ... tance.html

Regards
Christoph

pasha · **Joined:** Sat Nov 27, 2004 4:13 am **Posts:** 137

Well just use SINGLE_TABLE strategy, and then use SecondaryTables for your child entities:

Code:

@Entity
@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
@Table(schema = "scott", name = "tb_animal")
@SequenceGenerator(name = SimpleDomainObject.SEQUENCE_ALIAS, allocationSize = 1, sequenceName = "scott.sq_animal")
@DiscriminatorColumn(name = "brand")
public abstract class Animal extends SimpleDomainObject {
    @ManyToOne
    @JoinColumn(name = "fk_anm_mate")
    private Animal mate;

    public Animal getMate() {
        return mate;
    }

    public void setMate(Animal mate) {
        this.mate = mate;
    }
}

Code:

@Entity
@DiscriminatorValue("cat")
@SecondaryTable(schema = "scott", name = "tb_cat",
        pkJoinColumns = {@PrimaryKeyJoinColumn(name = "pk_animal", referencedColumnName = "id")})
public class Cat extends Animal {
    @Column(name = "color", table = "tb_cat")
    private String color;
    @Column(name = "name", table = "tb_cat")
    private String name;
    @Column(name = "birth_date", table = "tb_cat")
    private Date birthDate;

    public String getColor() {
        return color;
    }

    public void setColor(String color) {
        this.color = color;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Date getBirthDate() {
        return birthDate;
    }

    public void setBirthDate(Date birthDate) {
        this.birthDate = birthDate;
    }
}

Code:

public class Dog extends Animal {
    @Column(name = "race", table = "tb_dog")
    private String race;

    @Column(name = "weight", table = "tb_dog")
    private Float weight;

    public String getRace() {
        return race;
    }

    public void setRace(String race) {
        this.race = race;
    }

    public Float getWeight() {
        return weight;
    }

    public void setWeight(Float weight) {
        this.weight = weight;
    }
}