How can i map inheritance class in Hibernate :
For example i have abstract class figure and two child classes Square and Circle. How can i map them all to be in one table, for example "figures" ?
I have tried something like this
@Entity
@Table(name = "figures")
public abstract Figure{
}
@Entity
@Table(name = "figures")
public class Square extends Figure{
}
@Entity
@Table(name = "figures")
public class Circle extends Figure{
}
but it doesnt work.
Thanks for any help :)
What you need to do is add annotations to parent class :
@Entity
@Inheritance(strategy=InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(name="type", discriminatorType=DiscriminatorType.STRING)
@Table(name = "figures")
DiscriminatorColumn will be a new column created by hibernate to know what type this object is.
In my case I create a column with name "type"
And also annotations to all your child class
In DiscriminatorValue you need to insert a value that hibernate use to identify that class
In my case it is String. (discriminatorType in DiscriminatorColumn annotations)
@Entity
@DiscriminatorValue(V)
so in your case it could look like that :
@Entity
@Inheritance(strategy=InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(name="type", discriminatorType=DiscriminatorType.STRING)
@Table(name = "figures")
public class Figure{
}
@Entity
@DiscriminatorValue("S")
public class Square extends Figure{
}
@Entity
@DiscriminatorValue("C")
public class Circle extends Figure{
}
You can find more info here : http://www.javatpoint.com/hibernate-table-per-hierarchy-using-annotation-tutorial-example
