[jboss-user] [EJB 3.0] - EJB QL - Inheritence Query Question
costeen21
do-not-reply at jboss.com
Fri Jan 5 12:01:47 EST 2007
Assume the following environment:
I have a base abstract class setup for inheritence that has a Many-to-Many relationship with another class like:
| @Entity
| @Inheritance(strategy = InheritanceType.JOINED)
| public abstract class Automobile implements Serializable
| {
| private Set<Part> parts;
|
| @ManyToMany(mappedBy="parts")
| public Set<Part> getParts()
| {
| return parts;
| }
| }
|
| @Entity
| public class Part implements Serializable
| {
| private Set<Automobile> autos;
|
| @ManyToMany(cascade=CascadeType.ALL, fetch=FetchType.EAGER)
| public Set<Automobile> getAutomobiles()
| {
| return autos;
| }
| }
|
|
|
I have two classes that derive from my base calss.
| @Entity
| public class Car extends Automobile
|
| @Entity
| public class Truck extends Automobile
|
Can a EJB QL query be constructed such that I only get results for one of the derived classes?
Something like:
for this part get only the "Cars" associated with it.
SELECT auto FROM Autobile auto, IN(auto.parts) AS part where part=:specificPart and "Automobile instanceof Car"
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