Heritage Java web Inheritance

Question

I have the inheritance to do below and would like to know how it would look on main. Someone here could help?

Could you tell me if you have any problems with the mapping I did and how mainTeste would look? I cannot define the value of the Lancamentodesparcelado class...

I use: 1º the Eclipse; 2nd Oracle database and to view the database tables use oracle SQL Developer;
3º And in the project we will use the strategy of multiple tables with use of Join; I’ll put the beginning of the classes:

RELEASE

 @Entity
 @Inheritance(strategy = InheritanceType.JOINED)
 @DiscriminatorColumn(NAME="TIPO", discriminatorType=DiscriminatorType.CHAR)
 @Table(name="LANCAMENTO")
 public class Lancamento extends GenericModel{ ... }

LANCAMENTO_DESPESA

@Entity
public class LancamentoDespesa extends Lancamento{ ... }

LANCAMENTO_RECEITA

@Entity
public class LancamentoReceita extends Lancamento{ ... }

LANCAMENTO_DESPESA_PARCELADA

@Entity
public class LancamentoDespesa extends LancamentoDespesa{ 
    @Column(name = "PARCELA", nullable = true)
    private int numParcela;

    GET/SET...
}

Final remarks: In SQL Developer creates inheritance tables, but also creates 4 other tables with names:

HT_LANCAMENTO  
HT_LANCAMENTODESPESA  
HT_LANCAMENTORECEITA  
HT_LANCAMENTODESPESAPARCELADA  

And all have in the drawing of the table a little box with x.

I can’t get another picture in here if I wouldn’t.

Answer 1

Rafael, I copied the code and made the following changes for the generation of tabels to work:

RELEASE

@Entity
@Inheritance(strategy = InheritanceType.JOINED)
@DiscriminatorColumn(NAME="TIPO", discriminatorType=DiscriminatorType.INTEGER)
@Table(name="LANCAMENTO")
public class Lancamento extends GenericModel { ... }

LANCAMENTO_RECEITA

@Entity
@DiscriminatorValue("1")
public class LancamentoReceita extends Lancamento { ... }

LANCAMENTO_DESPESA

@Entity
@DiscriminatorValue("2")
public class LancamentoDespesa extends Lancamento { ... }

LANCAMENTO_DESPESA_PARCELADA

@Entity
@DiscriminatorValue("3")
public class LancamentoDespesa extends LancamentoDespesa { 
    @Column(name = "PARCELA", nullable = true)
    private int numParcela;

    GET/SET...
}

When using @Inheritance(strategy = InheritanceType.JOINED) and @DiscriminatorColumn, it is also necessary to use the annotation @DiscriminatorValue to define the value that will be used to distinguish the specific entity type.

In my example I changed to DiscriminatorType.INTEGER because using CHAR did not work with Hibernate in my tests.