DB inheritance mapping

[ipazmino]

Hi,

I have a hierarchy similar to the following:

abstract class Person {
    private String firstname;
    private String lastname;
    //getters & setters
}

class User extends Person {
    private String username;
    private String password;
    //getters & setters
}

class Visitor extends Person {
    private Date visitDate;
    //getters & setters
}

How can I map this into entites that can perform CRUD actions? And, how the actual tables in the DB would look like?

Thanks in advance,

IP

[joblini]

Hi, try the Hibernate user forum. 

[ipazmino]

Hi,

What I should do to make this hierarchy work as I want it to, I need to add some directives like

<class name="Payment" table="PAYMENT">
    <id name="id" type="long" column="PAYMENT_ID">
        <generator class="native"/>
    </id>
    <property name="amount" column="AMOUNT"/>
    ...
    <joined-subclass name="CreditCardPayment" table="CREDIT_PAYMENT">
        <key column="PAYMENT_ID"/>
        <property name="creditCardType" column="CCTYPE"/>
        ...
    </joined-subclass>
</class>

in the mapping descriptor for hibernate.
How can I modify the reveng.xml or persistence.xml file, so that I can have this configuration done when I generate the entities with the seam-gen tool?

Thanks in advance

IP

[benc.benc.alumni.psu.edu]

Or you can use annotations.  I've set it up to put all three in one table below.

@Entity
@Table(name = "person")
@Inheritance(strategy=InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(name="type", discriminatorType=DiscriminatorType.INTEGER)
abstract class Person {
    private String firstname;
    private String lastname;
    //getters & setters
}

@Entity
@Table(name = "person")
@DiscriminatorValue(value = "0")
class User extends Person {
    private String username;
    private String password;
    //getters & setters
}

@Entity
@Table(name = "person")
@DiscriminatorValue(value = "1")
class Visitor extends Person {
    private Date visitDate;
    //getters & setters
}