I have two entities, ShoppingCart and ShoppingCartLine. ShoppingCart has a collection of ShoppingCartLines. I am trying to create a JPA query using criteria to get a list of ShoppingCart ids and the number of ShoppingCartLines each ShoppingCart has.
Here is the mapping in the ShoppingCart class:
#OneToMany(mappedBy = "shoppingCart", fetch = FetchType.EAGER, cascade = CascadeType.ALL, orphanRemoval=true)
private Set<ShoppingCartLine> shoppingCartLines = new TreeSet<ShoppingCartLine>();
Here is the code I am attempting to create my JPA query with:
CriteriaBuilder cb = em.getCriteriaBuilder();
CriteriaQuery<Tuple> cq = cb.createTupleQuery();
Root<ShoppingCart> carts = cq.from( ShoppingCart.class );
Join<ShoppingCart, ShoppingCartLine> lines = carts.join( "shoppingCartLines", JoinType.LEFT);
cq.multiselect( carts.<Long>get( "id" ), cb.count( lines ));
cq.groupBy( carts.<Long>get("id") );
Query tq = em.createQuery( cq );
return tq.getResultList();
When I run this I get an SQLGrammerException, the SQL produced does not look correct to me.
select
shoppingca0_.id as col_0_0_,
count(.) as col_1_0_
from
SHOPPINGCART shoppingca0_
left outer join
SHOPPINGCARTLINE shoppingca1_
on shoppingca0_.id=shoppingca1_.shoppingCart_id,
SHOPPINGCARTLINE shoppingca2_
where
shoppingca0_.id=shoppingca2_.shoppingCart_id
group by
shoppingca0_.id
I should mention I am using Hibernate 3.5.4 with MySQL5Dialect
This is the query I am wanting to generate:
select
sc.id,
count(scl.id)
from
shoppingcart sc
left join
shoppingcartline scl
on
scl.shoppingCart_id = sc.id
group by
sc.id
Any idea what I'm doing wrong? Thanks.
Try to replace join and multiselect lines with
SetJoin<ShoppingCart, ShoppingCartLine> lines =
carts.joinSet( "shoppingCartLines", JoinType.LEFT);
cq.multiselect( carts.<Long>get( "id" ), cb.count( lines.<Long>get( "id" ) ));
Related
I'm trying to sort a list by the max date of a children class, using hibernate criteria:
Domain:
class Entity {
List<Children> childrens;
}
class Children {
Date date
}
Something like this in SQL:
SELECT
*
FROM
entity
INNER JOIN
children c1 ON c1.entity_id = entity.id
WHERE
c1.date =
(SELECT MAX(c2.date) FROM children c2 WHERE c2.entity_id = c1.entity_id)
ORDER BY
c1.date DESC
Does anyone know how to do this?
You can formulate something like that with HQL or the JPA Criteria API. Here is the HQL version:
from
Entity e
order by
(select max(c.date) from e.children c) desc
or with the Criteria API:
CriteriaBuiler cb = em.getCriteriaBuilder();
CriteriaQuery<Entity> q = cb.createQuery(Entity.class);
Root<Entity> r = q.from(Entity.class);
Subquery<Date> s = q.subquery(Date.class);
Join<?, ?> c = s.correlate(r).join("children");
s.select(cb.max(c.get("date")));
q.orderBy(cb.desc(s));
List<Entity> list = em.createQuery(q).getResultList();
Let's say I have the following SQL:
select * from table1
inner join table2 on table1.id = table2.table1id;
inner join table3 on table2.id = table3.table2id;
inner join table4 on table3.id = table4.table3id;
and I have Java entities like table1, table2, table3 and table4.
I want to map this query using criteria API. In order to do that I created class Table5 which contains all of fields of all classes.
Then I created a repository with the method:
public List<Table5> getAllTable5 () {
CriteriaBuilder cb = em.getCriteriaBuilder();
CriteriaQuery<Table5> query = cb.createQuery(Table5.class);
Root<Table1> root = query.from(Table1.class);
Join<Table1, Table2> table1Table2Join= root.join(Table1_.TABLE2);
Join<Table2, Table3> table2Table3Join= root.join(Table2_.TABLE3);
Join<Table3, Table4> table3Table4Join= root.join(Table3_.TABLE4);
query.multiselect(
root.get // all fields
);
TypedQuery<Table5> typedQuery = em.createQuery(query);
return typedQuery.getResultList();
}
Is it possible to create class like:
class Table5 {
private Table1 table1;
private Table2 table2;
private Table3 table3;
private Table4 table4;
// getters setters constructors
}
If yes, how should getAllTable5 method look like?
You can either select every table entity, or select just the first one and rely on join fetching.
public List<Table5> getAllTable5 () {
CriteriaBuilder cb = em.getCriteriaBuilder();
CriteriaQuery<Table1> query = cb.createQuery(Table1.class);
Root<Table1> root = query.from(Table1.class);
query.select(root);
TypedQuery<Table1> typedQuery = em.createQuery(query);
EntityGraph entityGraph = em.createEntityGraph();
// Apply subgraphs for the associations to fetch
typedQuery.setHint("javax.persistence.loadgraph", entityGraph);
List<Table1> list = typedQuery.getResultList();
List<Table5> table5s = new ArrayList<>(list.size());
for (Table1 t : list) {
table5s.add(new Table5(t, t.getTable2(), , t.getTable2().getTable3(), , t.getTable2().getTable3().getTable4());
}
return table5s;
}
Based on this answer https://stackoverflow.com/a/2111420/3989524 I first created a working SQL:
SELECT d.*
FROM device d
LEFT OUTER JOIN installation_record ir1 ON (d.id = ir1.device)
LEFT OUTER JOIN installation_record ir2 ON (d.id = ir2.device AND ir1.install_date < ir2.install_date)
WHERE ir2.id IS NULL AND ir1.uninstall_date IS NULL;
and then a criteria query which looks to produce an equivalent HQL (in the end), but Hibernate throws an error:
org.hibernate.hql.internal.ast.QuerySyntaxException: with-clause referenced two different from-clause elements
The HQL from the error message:
SELECT generatedAlias0 FROM Device AS generatedAlias0
LEFT JOIN generatedAlias0.installationRecordList AS generatedAlias1
LEFT JOIN generatedAlias0.installationRecordList AS generatedAlias2
WITH generatedAlias1.installDate<generatedAlias2.installDate
WHERE ( generatedAlias2.id IS NULL ) AND ( generatedAlias1.uninstallDate IS NULL )
The criteria query:
final CriteriaBuilder cb = em.getCriteriaBuilder();
final CriteriaQuery<Device> cq = cb.createQuery(Device.class);
final Root<Device> root = cq.from(Device.class);
final Join<Device, InstallationRecord> join1 = root.join(Device_.installationRecordList, JoinType.LEFT);
final Join<Device, InstallationRecord> join2 = root.join(Device_.installationRecordList, JoinType.LEFT);
join2.on(cb.lessThan(join1.get(InstallationRecord_.installDate), join2.get(InstallationRecord_.installDate)));
cq.select(root);
final List<Predicate> predicates = Lists.newArrayList();
predicates.add(cb.isNull(join2.get(InstallationRecord_.id)));
predicates.add(cb.isNull(join1.get(InstallationRecord_.uninstallDate)));
cq.where(predicates.toArray(new Predicate[] {}));
return em.createQuery(cq).getResultList();
Is there anyway to get what I want or there no other way around some internal hibernate bug.
Maybe:
final Join<InstallationRecord, InstallationRecord> join2 = root.join(InstallationRecord_.id, JoinType.LEFT);
because ON (d.id = ir2.device AND is missing in the HQL.
When attempting to generate dynamic queries using CriteriaBuilder, Hibernate is not creating the proper SQL with regards to an Entities member variable associated with #ElementCollection.
Sample Entity:
#Entity
#Table(name = "myclass")
public class MyClass {
...
#ElementCollection
#CollectionTable(
name = "myclass_mysubclass",
joinColumns = #JoinColumn(name = "myclass_id")
)
#Column(name = "mysubclass_id")
private List<Integer> mySubClassIDs;
...
}
CriteriaBuilder code:
CriteriaBuilder criteriaBuilder = getEntityManager().getCriteriaBuilder();
CriteriaQuery criteriaQuery = criteriaBuilder.createQuery(MyClass.class);
Root<T> root = criteriaQuery.from(MyClass.class);
Expression<Object> e = root.get("mySubClassIDs");
List<Object> o = (List<Object>) entry.getValue();
criteriaQuery.where(e.in(o));
where entry.getValue() will return an ArrayList<Integer> of [1]
Produces:
SELECT distinct count(myclass0_.id) as col_0_0_
FROM hotel myclass0_
cross join myclass_mysubclass mySubClassids1_
where myclass0_.id=mySubClassids1_.myclass_id and (. in (1))
Why is Hibernate not generating the "in" clause properly? the "." should be mySubClassids1_.mysubclass_id
Am I missing something in the annotation of the member variable? Doesn't seem so, as it is enough to generate the cross join.
The env is Jboss AS 7 with Hibernate 4.2.7.SP1-redhat-3 on jdk-6
Your schema is creating two separate tables:
create table myclass (
id int8 not null,
primary key (id)
);
create table myclass_mysubclass (
myclass_id int8 not null,
mysubclass_id int4
);
So, it seems you need to do a join instead of a get:
Expression<Object> e = root.join("mySubClassIDs");
Worked for me at any rate.
I have following jpa criteria query:
CriteriaBuilder cb = em.getCriteriaBuilder();
CriteriaQuery<Company> cq = cb.createQuery(Company.class);
Root<Company> root = cq.from(Company.class);
cq.select(root);
Subquery<String> sq = cq.subquery(String.class);
Root<Employee> subroot = sq.from(Employee.class);
sq.select(subroot.get(Employee_.lastName));
Predicate typePredicate = cb.equal(subroot.get(Employee_.lastName), "Doe");
Predicate correlatePredicate = cb.equal(root.get(Company_.employees), subroot);
sq.where(cb.and(typePredicate, correlatePredicate));
cq.where(cb.exists(sq));
TypedQuery<Company> typedQuery = em.createQuery(cq);
List<Company> companies = typedQuery.getResultList();
Eclipselink produces following SQL:
SELECT t0.ID, ... FROM COMPANY t0
WHERE EXISTS (SELECT t1.LASTNAME FROM EMPLOYEES t2, EMPLOYEES t1
WHERE (((t1.LASTNAME = ?) AND (t1.ID = t2.ID))
AND (t2.COMPANY_ID = t0.ID)))
As you can see there is an unneccessary join on table EMPLOYEES. How do I get rid of this join?
You don't seem to need a subquery for the query, just a join should be enough,
http://en.wikibooks.org/wiki/Java_Persistence/Criteria#Join
Otherwise, what version are you using? Can you try EclipseLink 2.4.
If it still has the duplicate, please log a bug and vote for it.
You might be able to use the inverse ManyToOne, instead of the OneToMany (i.e. root == subroot.get("company") ).
Also try JPQL in 2.4, is the join optimized?