How to dynamically order many-to-many relationship in JPA or HQl?

Posted by Indrek on Stack Overflow See other posts from Stack Overflow or by Indrek
Published on 2010-06-08T23:37:55Z Indexed on 2010/06/08 23:42 UTC
Read the original article Hit count: 262

Filed under:

jpa

|

many-to-many

|

hql

|

order-by

|

play-framework

I have a mapping like this:

@ManyToMany(cascade = CascadeType.PERSIST)
    @JoinTable(
            name="product_product_catalog",
            joinColumns={@JoinColumn(name="product_catalog", referencedColumnName="product_catalog")},
            inverseJoinColumns={@JoinColumn(name="product", referencedColumnName="product")})
    public List<Product> products = new ArrayList<Product>();

I can fetch the products for the catalog nicely, but I can't (dynamically) order the products. How could I order them? I probably have to write a many-to-many HQL query with the order-by clause? I though of passing the orderBy field name string to the query, or is there a better solution?

Tables are: products, product_catalog, product_product_catalog (associative table)

P.S. Using Play! Framework JPASupport for my entities.

© Stack Overflow or respective owner

Related posts about jpa

Detach an entity from a JPA persistence context (JPA 2.0 / Hibernate / EJB 3 / J2EE 6)

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi, I wrote a stateless EJB method allowing to get an entity in "read-only" mode. The way to do this is to get the entity with the EntityManager then detach it (using the JPA 2.0 EntityManager). My code is the following: @PersistenceContext private EntityManager entityManager; public T getEntity(int… >>> More
AndroMDA maven code generation and JPA Annotations

as seen on Stack Overflow - Search for 'Stack Overflow'
I am using the AndroMDA plugin for maven to generate code from an uml diagram made in MagicDraw. When the code is generated, AndroMDA desings the JPA annotation for the persitence layer. I think that at the compilation process AndroMDA uses Naming Strategies to determine the Table and Column names… >>> More
How to populate Java (web) application with initial data using Spring/JPA/Hibernate

as seen on Stack Overflow - Search for 'Stack Overflow'
I want to setup my database with initial data programmatically. I want to populate my database for development runs, not for testing runs (it's easy). The product is built on top of Spring and JPA/Hibernate. Developer checks out the project Developer runs command/script to setup database with initial… >>> More
Eclipselink problem in a javase project

as seen on Stack Overflow - Search for 'Stack Overflow'
I am getting this error when I am running my eclipselink project. [EL Warning]: 2008.12.05 11:47:08.056--java.lang.NoClassDefFoundError: org/jboss/resource/adapter/jdbc/ValidConnectionChecker was thrown on attempt of PersistenceLoadProcessor to load class com.mysql.jdbc.integration.jboss.MysqlValidConnectionChecker… >>> More
JPA thinks I'm deleting a detached object

as seen on Stack Overflow - Search for 'Stack Overflow'
So, I've got a DAO that I used to load and save my domain objects using JPA. I finally managed to get the transaction stuff working (with a bunch of help from the folks here...), now I've got another issue. In my test case, I call my DAO to load a domain object with a given id, check that it got… >>> More

Related posts about many-to-many

Self referencing symmetrical Hibernate Map Table using @ManyToMany

as seen on Stack Overflow - Search for 'Stack Overflow'
I have the following class public class ElementBean { private String link; private Set<ElementBean> connections; } I need to create a map table where elements are mapped to each other in a many-to-many symmetrical relationship. @ManyToMany(targetEntity=ElementBean.class) @JoinTable( … >>> More
Django ManyToMany join query

as seen on Stack Overflow - Search for 'Stack Overflow'
I'm sure this is really simple, but I can't for the life of me find any documentation explaining how to do this. How do I get the results of a ManyToMany field inside a join as opposed to doing this: {% for tag in article.tags.all %} Which results in an extra query? What I'd like to do is fetch… >>> More
django ManyToMany through help

as seen on Stack Overflow - Search for 'Stack Overflow'
Hay I've got a question about relationships. I want to Users to have Friendships. So a User can be a friend with another User. I'm assuming i'll need to use the ManyToManyField, through a Friendship table. But i cannot get it to work. Any ideas? Here are my models. class User(models.Model): … >>> More
Limiting choices from an intermediary ManyToMany junction table in Django

as seen on Stack Overflow - Search for 'Stack Overflow'
Background I've created three Django models—Inventory, SalesOrder, and Invoice—to model items in inventory, sales orders for those items, and invoices for a particular sales order. Each sales order can have multiple items, so I've used an intermediary junction table—SalesOrderItems—using the through… >>> More
What's best practice to check if an object is part of a ManyToMany relationship in Django

as seen on Stack Overflow - Search for 'Stack Overflow'
from an instance of Site with a ManyToMany relationship to Kiosk, i'd like to check if a Kiosk object is part of the relationship. I could do self.apps.get(id=app_id).exists() and check if True or self.apps.get(id=app_id) and catch the ObjectDoesNotExist error or self.apps.filter(id=app_id)… >>> More