InheritanceType.TABLE_PER_CLASS don't work ?

[infodavid]

Hi,

I have tried this code :

@EmbeddableSuperclass(access = AccessType.PROPERTY)
public abstract class AbstractSimpleEntity implements Serializable, ISimpleObject { ... }

@javax.persistence.Entity(access = AccessType.PROPERTY)
@Table(name = "ENTITIES")
@Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)
public class Entity extends AbstractSimpleEntity implements IEntity { ... }

Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)
@Entity(access = AccessType.PROPERTY)
@Table(name = "PERSONS")
@Remote(IPerson.class)
public class Person extends org.infodavid.par.Entity implements IPerson { ... }

but two tables are created with all the fields.
I would like to create two tables 'ENTITIES' and 'PERSONS' :

CREATE TABLE ENTITIES (
entity_id INTEGER GENERATED BY DEFAULT AS IDENTITY (START WITH 0, INCREMENT BY 1) PRIMARY KEY,
name VARCHAR(32) NOT NULL,
...
)

CREATE TABLE PERSONS (
person_id INTEGER GENERATED BY DEFAULT AS IDENTITY(START WITH 0, INCREMENT BY 1) PRIMARY KEY,
...
entity_id INTEGER NOT NULL,
FOREIGN KEY (entity_id) REFERENCES ENTITIES(entity_id) ON DELETE CASCADE,
)

[epbernard]

so it's a JOINED inheritance strategy

[infodavid]

Can you give me an example because I have tried this strategy and something did not work in my code.

Thanks for all ;)

[infodavid]

here is the trouble, eclipse can't found annotation :
@InheritanceJoinColumn

I use Jboss 4.0.1RC1 with the ejb3 deployer.

[infodavid]

Now I have :

@javax.persistence.Entity(access = AccessType.PROPERTY)
@Table(name = "ENTITIES")
@Inheritance(strategy = InheritanceType.JOINED)
public class Entity extends AbstractSimpleEntity implements IEntity {
@Id(generate = GeneratorType.TABLE)
@Column(name = "entity_id", nullable = false, unique = true)
public long getPrimaryKey() { return id; }
...
}

and

@Entity(access = AccessType.PROPERTY)
@Table(name = "PERSONS")
@Inheritance(strategy = InheritanceType.JOINED)
@PrimaryKeyJoinColumns( { @PrimaryKeyJoinColumn( name = "entity_id", referencedColumnName = "entity_id") } )
@Remote(IPerson.class)
public class Person extends org.infodavid.par.Entity implements IPerson { ... }

the first table is ok,
the second table seems not ok because the only key I have is 'entity_id' and no second key like 'person_id'. See :

CREATE TABLE PERSONS (
person_id INTEGER GENERATED BY DEFAULT AS IDENTITY(START WITH 0, INCREMENT BY 1) PRIMARY KEY,
...
entity_id INTEGER NOT NULL,
FOREIGN KEY (entity_id) REFERENCES ENTITIES(entity_id) ON DELETE CASCADE,
)

How can it work if a person has the same id as the entity ? I would like to create an other subclass of 'Entity' (like Company or something like this) and I don't understand how it can work.

[epbernard]

I don't see why it fails, what is the full code of the annotated classes?
Hibernate shouldn't generate 'person_id'

[infodavid]

First, Thanks for all.

Here is the full code :

For Entity :

@javax.persistence.Entity(access = AccessType.PROPERTY)
@Table(name = "ENTITIES")
@Inheritance(strategy = InheritanceType.JOINED)
public class Entity extends AbstractSimpleEntity implements IEntity {
 private String address = null;
 private City city = null;

 public Entity() { }

 public Entity(Entity o) { super(o); }

 @Id(generate = GeneratorType.TABLE)
 @Column(name = "entity_id", nullable = false, unique = true)
 public long getPrimaryKey() { return id; }

 @Column(name = "address", nullable = true, unique = false, length = 255)
 @Length(min = 0, max = 255)
 public String getAddress() throws RemoteException { return address; }

 public void setAddress(String s) throws RemoteException { address = s; }

 @ManyToOne(fetch = FetchType.LAZY)
 @JoinColumn(name = "city_id")
 public City getCity() throws RemoteException { return city; }

 public void setCity(Object o) throws RemoteException { city = (City)o; }
}

for Person :

@Entity(access = AccessType.PROPERTY)
@Table(name = "PERSONS")
@Inheritance(strategy = InheritanceType.JOINED)
@PrimaryKeyJoinColumns( { @PrimaryKeyJoinColumn( name = "entity_id", referencedColumnName = "entity_id") } )
@Remote(IPerson.class)
public class Person extends org.infodavid.par.Entity implements IPerson {
 private String firstname = null;
 private PersonTitle title = null;

 public Person() { }

 public Person(Person o) { super(o); }

 @ManyToOne(fetch = FetchType.LAZY)
 @JoinColumn(name = "title_id")
 public PersonTitle getTitle() throws RemoteException { return title; }

 public void setTitle(Object o) throws RemoteException { title = (PersonTitle)o; }

 @Column(name = "firstname", nullable = true, unique = false, length = 48)
 @Length(min = 0, max = 48)
 public String getFirstname() throws RemoteException { return firstname; }

 public void setFirstname(String s) throws RemoteException { firstname = s; }
}

and the generated tables :

For Entity :

CREATE MEMORY TABLE ENTITY(
ENTITY_ID BIGINT NOT NULL PRIMARY KEY,
ADDRESS VARCHAR(255),
CITY_ID BIGINT,CONSTRAINT SYS_CT_12 UNIQUE(ENTITY_ID),
CONSTRAINT FK7C02D003F09E40D9 FOREIGN KEY(CITY_ID) REFERENCES CITY(CITY_ID))

for Person :

CREATE MEMORY TABLE PERSONS(
ENTITY_ID BIGINT NOT NULL PRIMARY KEY,
FIRSTNAME VARCHAR(48),(15),
TITLE_ID BIGINT,
CONSTRAINT FK25B5B9E5B91CA19 FOREIGN KEY(ENTITY_ID) REFERENCES ENTITY(ENTITY_ID))

ALTER TABLE PERSONS ADD CONSTRAINT FK25B5B9E6DE21C86 FOREIGN KEY(TITLE_ID) REFERENCES PERSONTITLE(TITLE_ID)

So when I add a 'Person', what is done ? In my other version (simple jdbc), I add an 'Entity' record for each 'Person' using the 'Entity' generated key in the column 'entity_id' of the new 'Person'.

Many thanks for your help.

[infodavid]

You can see my other post for more informations if needed

http://www.jboss.org/index.html?module=bb&op=viewtopic&t=69327

[epbernard]

OK so Hibernate is working as I'm expecting.

You ask it to create a person table with a PK/FK to Entities names entity_id

@PrimaryKeyJoinColumns( { @PrimaryKeyJoinColumn( name = "person_id", referencedColumnName = "entity_id") } )

would have created a PK/FK named person_id

To load a person, Hibernate do an inner join between Entities and Persons using this FK.

[infodavid]

Thanks it works for 'Person', now I'll try using another subclass of 'Entity'.

Thanks for all Emmanuel,
Merci beaucoup.

[infodavid]

Tout va marche bien, merci encore.