What is the object type returning in a join of a hibernate query

Question

When I have the below query it will give me a list of Product.

List<Product>=

getCurrentSession().createQuery("SELECT p FROM Product p ").list();

What will it return when there is a join as below.

getCurrentSession().createQuery("SELECT p FROM Product p inner join ProductCategory pc where p.id=pc.id").list();

Why don't you try it yourself and see what it returns? Is it really that difficult? — RainMaker, May 02 '13 at 05:05

score 4 · Accepted Answer · answered May 02 '13 at 05:06

4

SELECT p FROM Product p inner join ... something like that gives you a list of Products.

FROM Product p inner join ... something like that gives you a list of arrays.

answered May 02 '13 at 05:06

Bhesh Gurung

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Can you please tell what is the reason for that? – Kulbhushan Singh Oct 25 '17 at 10:58
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Both are joining tables but the 1st explicitly specifies to return only Product. – Bhesh Gurung Oct 25 '17 at 13:03

score 4 · Answer 2 · edited May 23 '17 at 11:47

4

It should return List<Object[]> as a result. Please see this thread

And you should access your entities like

for (Object[]> result : query.list()) {
    Product p = (Product) result[0];
    ProductCategory pc = (ProductCategory) result[1];
}

edited May 23 '17 at 11:47

Community

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answered May 02 '13 at 05:13

sanbhat

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score 1 · Answer 3 · edited May 02 '13 at 05:10

1

This will return a list of objects. You will have to cast them in to Product

List list = session.createQuery("SELECT p FROM Product p inner 
                      join ProductCategory pc where p.id=pc.id").list();

edited May 02 '13 at 05:10

phenom

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answered May 02 '13 at 05:04

Suresh Atta

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score 0 · Answer 4 · answered May 02 '13 at 05:06

0

According to the documentation for javax.persistence.Query, you are going to get a List back. Why would you think it should be different?

answered May 02 '13 at 05:06

hd1

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score 0 · Answer 5 · edited Jun 24 '16 at 09:58

This class casting from java.lang.object to model class doesn't work in any ways. Below is my code.

List<Contactinfo> listStudentInfo = new ArrayList<Contactinfo>();                    
                         //listStudentInfo = dataService.getAllStudent(studentInfo);
                         listStudentInfo = dataService.getStudentInfo();
                         System.out.println(listStudentInfo.size()); 
                         Contactinfo contactinfo = (Contactinfo)listStudentInfo.get(0);

But In hibernate, you don't need join if you have both Entity associated with by @Many-to-one or @One-to-one join annotation. Then you need to select one object only , you will automatically get access to other object via the join. Make sure you keep getter(), setter() method for the joining field. Hope this will clarify the situation.

What is the object type returning in a join of a hibernate query

5 Answers5