Question

Assume

@Entity 
Class Animals { }

@Entity
@Inheritance( stragegy = InheritanceType.JOINED)
class Dogs extends Animals {
    private String furType;
}

@Entity
@Inheritance( stragegy = InheritanceType.JOINED)
class Cat extends Animals {
    private String furType;
}

All entities are real classes in my database and I don t have the option of redesigning our database.

How can I used a DetactedCriteria to create a disjunction query that says give me all "Animals" where furType= loud for dogs OR furType= soft for cats? Sorry I didn t design the class hierarchy so I m not responsible for the fact that the property names are the same and I can t redesign it because there are other subclasses who s tables don t contain "furType".

Answer 1

在JPA 2.0中,你可以使用TYPE()建造工作。与此类似(未经检查)的一些工作是:

SELECT a 
  FROM Animals a 
  WHERE (TYPE(a) = Dogs AND a.furType =  loud ) OR 
        (TYPE(a) = Cat AND a.furType =  soft )

友情链接