问题
I have a Person entity mapped by Hibernate to a database table in a database catalog "Active". After a period of time, records in this database table in the "Active" catalog are archived/moved to an exact copy of the table in a database Catalog "History". I have the need to retrieve from both the Active and History Catalogs. Is there a better way to model this with Hibernate annotations than making an abstract class that 2 classes extend from.
This is what I have now.
@MappedSuperclass
public abstract class Person {
@Id
private Integer id;
private String name;
}
@Entity
@Table(name="Person", catalog="Active")
public class PersonActive extends Person {
}
@Entity
@Table(name="Person", catalog="History")
public class PersonHistory extends Person {
}
回答1:
To my knowledge, that would be the right way to do it with annotations (you kinda have two tables so you need two entities). Then run a polymorphic query on the Person entity. I find this pretty clean by the way.
PS: Can you add a pointer on how to do this with mapping files, I'm really curious.
回答2:
My thought would be to write a query to select both tables from db A and B. then create a query with hibernate and map it to your class.
example:
@Entity
@NamedNativeQuery(
name="GetAllPerson",
query="select * from A.Person inner join B.Person on A.Person.Id = B.Person.Id"
)
public class Person {
...
}
Not sure if it could work, your question made me also curious about the best way to do it :). I'll test it tonight after work and see if its any good.
回答3:
I think there is a subproject of hibernate named shards. It is designed to work with multiple relational databases. If you want to use it, you may need big changes in your code.
来源：https://stackoverflow.com/questions/2380754/hibernate-annotation-for-entity-existing-in-more-than-1-catalog