criteria-api

I'm building my first Java EE web application using Glassfish and JSF. I'm fairly new to the criteria query and I have a query I need to perform but the javaee6 tutorial seems a little thin on examples. Anyway, I'm having a hard time creating the query. Goal: I want to pull the company with the most documents stored. Companies have a OneToMany relationship with Documents. Documents has a ManyToOne relationship with several tables, the "usertype" column distinguishes them. MySQL query: SELECT USERID, COUNT(USERID) AS CNT FROM DOCUMENTS WHERE USERTYPE="COMPANY" GROUP BY USERID ORDER BY CNT DESC

So, After a 10+ year break I'm coming back to Java and trying out stuff with JPA and Java generics. I've created a generics based findAll(other) JPA query that basically does SELECT * FROM source WHERE other_id = other.id; This is where I'm up to. It works, but I'm wondering if there's a better, cleaner way to do it. Using ManagedType was hard, and there's not much complete documentation or simple examples around. I've decided to keep my code as generic as possible (no pun intended) so I use JPA2. This is the root of all Entity Classes. I probably don't need it, but it stops me from having

I'm trying to use Criteria API in my new project: public List<Employee> findEmps(String name) { CriteriaBuilder cb = em.getCriteriaBuilder(); CriteriaQuery<Employee> c = cb.createQuery(Employee.class); Root<Employee> emp = c.from(Employee.class); c.select(emp); c.distinct(emp); List<Predicate> criteria = new ArrayList<Predicate>(); if (name != null) { ParameterExpression<String> p = cb.parameter(String.class, "name"); criteria.add(cb.equal(emp.get("name"), p)); } /* ... */ if (criteria.size() == 0) { throw new RuntimeException("no criteria"); } else if (criteria.size() == 1) { c.where(criteria

My Java application is using JPA for object persistence. The business domain is very simple (just three classes are persistent, with 3-5 properties in each). Queries are simple as well. The question is which approach I should use: JPQL or Criteria API? Pascal Thivent I'm pretty sure this has already been covered here on SO but I couldn't find the existing question. So, here is my point of view on the question: I find JPQL queries easier to write/read. I find the Criteria API nice for building dynamic queries. Which is basically what you'll find in Hibernate: Criteria vs. HQL . But there is one

I have a data model where an account can have multiple users: class Account { Long id; } class User { Long id; @ManyToOne Account account; } I'd like to do the following query which displays the number of users of each account: select Account.id, NumUsers.num from Account, (select Account.id as account_id, count(User.id) as num from User join Account on User.account_id=Account.id group by Account.id) as NumUsers where Account.id=NumUsers.account_id; I know I can re-write this specific query as: select Account.id, count(User.id) from Account join User on User.account_id=Account.id group by

I am trying to write a query with subselect where a string is cast to a long. I'm probably missing something? Query looks like: CriteriaBuilder cb = em.getCriteriaBuilder(); CriteriaQuery<Task> query = cb.createQuery(Task.class); Root<Task> from = query.from(Task.class); Subquery<Long> subquery = query.subquery(Long.class); Root<EntityKeyword> fromKeyword = subquery.from(EntityKeyword.class); subquery.select(fromKeyword.get(EntityKeyword_.relatedToId).as(Long.class)); subquery.where(cb.like(fromKeyword.get(EntityKeyword_.keyword), term)); query.where(cb.in(from.get(ModelEntity_.id)).value

Is there a way to write with JPA 2 CriteriaBuilder the equivalent of the following query? select * from season s1 where end = ( select max(end) from season s2 where s1.contest_id=s2.contest_id ); In JPQL this query is: Select s1 from Season s1 where s1.end = ( select max(s2.end) from Season s2 where s1.contest=s2.contest ) This should work, with contest being either a basic Integer property, or a ManyToOne property pointing to another non-basic Entity. EntityManger em; //to be injected or constructed CriteriaBuilder cb = em.getCriteriaBuilder(); CriteriaQuery<Season> cq = cb.createQuery(Season

I have a join reference like following for which the first join expression is constructed by the JPA API automatically. CriteriaBuilder cb = entityManager.getCriteriaBuilder(); CriteriaQuery<Tuple> c = cb.createTupleQuery(); Root<Demand> demands = c.from(Demand.class); Join<Demand, Metadata> joinMetadata = demands.join("metadatas", JoinType.LEFT); but, I would like to add an aditional condition to my joinMetadata like Metadata.type="AFFECTATION_KEY" but I don't know how. Many thanks for any help James JPA always joins by the mapping join columns, only. JPA 2.0 does not support an ON clause,