My goal is to make a method with which I can retrieve the total number of rows from any table in my database.
This is what I have done:
ENTITY_MANAGER_FACTORY = Persistence.createEntityManagerFactory(PERSISTENCE_UNIT);
EM = ENTITY_MANAGER_FACTORY.createEntityManager();
public static long getRowCount(Root<?> root) {
CriteriaBuilder cb = EM.getCriteriaBuilder();
CriteriaQuery<Long> query = cb.createQuery(Long.class);
root = query.from(root.getClass());
query.select(cb.count(root));
return EM.createQuery(query).getSingleResult();
}
This is how I call the method:
Root<PlacesEntity> placesRoot = null;
DbTools.getRowCount(placesRoot)
It is not working though, the method throws a NullPointerException at the line root = query.from(root.getClass());.
Try this (warning not tested):
public static long getRowCount(Class<?> rootClass) {
CriteriaBuilder cb = EM.getCriteriaBuilder();
CriteriaQuery<Long> query = cb.createQuery(Long.class);
Expression<?> root = query.from(rootClass);
query.select(cb.count(root));
return EM.createQuery(query).getSingleResult();
}
/*****/
DbTools.getRowCount(PlacesEntity.class);
Good luck!
Related
#Query(value = "select usd from UserDetail usd where usd.phoneNumber=:phoneNumber")
Optional<UserDetail> findByPhoneNumber(#Valid #Param("phoneNumber") String phoneNumber);
This is my JPQL query method and I am here using return type with Optional. I wonder how to write using CriteriaBuilder?
I wrote like this but I am getting an error.
#Override
public Optional<UserDetail> findByCreatedDate(String phoneNumber) {
CriteriaBuilder cb = em.getCriteriaBuilder();
CriteriaQuery<UserDetail> cq = cb.createQuery(UserDetail.class);
Root<UserDetail> root = cq.from(UserDetail.class);
cq.where(cb.equal(root.get("phoneNumber"), phoneNumber))
.orderBy(cb.desc(root.get("phoneNumber")));
return em.createQuery(cq).getResultList().get(3);
}
If the method return type is Optional that is what exactly you must return.
The line em.createQuery(cq).getResultList().get(3) returns only UserDetail so you need to wrap it to Optional.of:
#Override
public Optional<UserDetail> findByCreatedDate(String phoneNumber) {
CriteriaBuilder cb = em.getCriteriaBuilder();
CriteriaQuery<UserDetail> cq = cb.createQuery(UserDetail.class);
Root<UserDetail> root = cq.from(UserDetail.class);
cq.where(cb.equal(root.get("phoneNumber"), phoneNumber))
.orderBy(cb.desc(root.get("phoneNumber")));
return Optional.of(em.createQuery(cq).getResultList().get(3));
}
By the way, are you sure the hardcoded .get(3) is what you want? If the list is empty or has less than 4 elements, it would throw a runtime exception.
if a phone number is associated with only one person why are you trying to get a list ?
have a look to this :
#Override
public Optional<UserDetail> findByCreatedDate(String phoneNumber) {
CriteriaBuilder cb = em.getCriteriaBuilder();
CriteriaQuery<UserDetail> cq = cb.createQuery(UserDetail.class);
Root<UserDetail> root = cq.from(UserDetail.class);
cq.where(cb.equal(root.get("phoneNumber"), phoneNumber)).orderBy(cb.desc(root.get("phoneNumber")));
UserDetail ud = em.createQuery(cq).getSingleResult();
return ud == null ? Optional.empty() : Optional.of(ud)
}
Regards,
I try to search a list keyword on 2 different table by CriteriaBuilder and get performance issue on line 26.
Can someone help me to improve this.
public static Specification<TrainingBatchVolunteerDetails> filterVolunteers(final TrainingVolunteerForm form) {
return new Specification<TrainingBatchVolunteerDetails>() {
#Override
public Predicate toPredicate(Root<TrainingBatchVolunteerDetails> root,
CriteriaQuery<?> query, CriteriaBuilder cb) {
....
List<Predicate> predicates = new ArrayList<Predicate>();
Join<TrainingBatchVolunteerDetails, TrainingBatches> batches = root.join("batches");
Join<TrainingBatches, Training> training = batches.join("training");
training.join("trainingVolunteerDetails").join("eventBaseProfile");
Join<TrainingBatches, EventBaseProfile> eventBaseProfile = root.join("eventBaseProfile");
Join<EventBaseProfile, BaseProfile> baseProfile = eventBaseProfile.join("baseProfile");
Join<CtExtendProfile, BaseProfile> ctExtendProfile = null;
if (StringUtils.isNotEmpty(form.getNricName())) {
...
ctExtendProfile = baseProfile.join("ctExtendProfile", JoinType.LEFT);
List<String> keywords = new ArrayList<String>();
...
predicates.add(cb.or(
baseProfile.<String>get("identifierId").in(keywords),
ctExtendProfile.<String>get("birthCertificate").in(keywords)
));
}
return cb.and(predicates.toArray(new Predicate[predicates.size()]));
}
};
}
I have selection parameters on flat data, only don't know how to either omit a parameter entirely, or make it a complete wildcard. The search might use one or all parameters. How is this done? With ANY or ALL? Or, is there another way?
I would like to use one general query with all the paremeters, and pass in "all" or "any", something along those lines, for some of those parameters.
existing code:
package legacy.database;
import java.sql.Timestamp;
import java.util.List;
import java.util.logging.Logger;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
import javax.persistence.Query;
public class MyQueries {
private static final Logger log = Logger.getLogger(MyQueries.class.getName());
private final EntityManagerFactory emf = Persistence.createEntityManagerFactory("LegacyDatabasePU");
private final EntityManager em = emf.createEntityManager();
public MyQueries() {
}
public List<Clients> findAll() {
Query q = em.createQuery("select c from Clients c");
List<Clients> clients = q.getResultList();
return clients;
}
public List<Clients> selectWithParameters(Criteria c) {
log.info(c.toString());
String opener = c.getOpener();
String closer1 = c.getCloser1();
String status = c.getStatus();
Query q = em.createQuery(
"SELECT c FROM Clients c "
+ "WHERE c.status like :status "
+ "and c.closer1 like :closer1 "
+ "and c.opener like :opener");
q.setParameter("opener", opener);
q.setParameter("closer1", closer1);
q.setParameter("status", status);
log.info(q.toString());
List<Clients> clients = q.getResultList();
log.fine(clients.toString());
return clients;
}
public Clients findById(int id) {
Clients client = em.find(Clients.class, id);
return client;
}
public void send(int id) {
Clients c = em.find(Clients.class, id);
java.util.Date date = new java.util.Date();
Timestamp t = new Timestamp(date.getTime());
em.getTransaction().begin();
c.setDateUpdated(t.toString());
em.getTransaction().commit();
}
}
In case the parameters are optional, the criteria API provides some more flexibility.
If the selectWithParameters is called often, consider using parameters, since the DB can cache the parametrized query then.
selectWithParameters with optional parameters reads like this:
public List<Clients> selectWithParameters(Criteria criteria) {
log.info(criteria.toString());
String opener = criteria.getOpener();
String closer1 = criteria.getCloser1();
String status = criteria.getStatus();
CriteriaBuilder criteriaBuilder = em.getCriteriaBuilder();
CriteriaQuery<Clients> query = criteriaBuilder.createQuery(Clients.class);
Root<Clients> c = query.from(Clients.class);
List<Predicate> wherePredicates = new LinkedList<Predicate>();
if (null != status) {
wherePredicates.add(criteriaBuilder.like(c.get("status"), status));
}
if (null != closer1) {
wherePredicates.add(criteriaBuilder.like(c.get("closer1"), closer1));
}
if (null != opener) {
wherePredicates.add(criteriaBuilder.like(c.get("opener"), opener));
}
query.where(wherePredicates.toArray(new Predicate[0]));
List<Clients> clients = em.createQuery(query).getResultList();
log.fine(clients.toString());
return clients;
}
Thank you, Heiner. This worked, not sure why I had trouble with Heiner's code, but his sample put me in the right direction:
public List<Clients> selectByCriteria(Criteria criteria) {
CriteriaBuilder criteriaBuilder = em.getCriteriaBuilder();
CriteriaQuery<Clients> clientCriteriaQuery = criteriaBuilder.createQuery(Clients.class);
Root<Clients> clientRoot = clientCriteriaQuery.from(Clients.class);
clientCriteriaQuery.select(clientRoot);
List<Predicate> predicates = new ArrayList<>();
predicates.add(criteriaBuilder.like(clientRoot.get(Clients_.phone1), "%" + criteria.getPhone1() + "%"));
if (!criteria.getOpener().equalsIgnoreCase("all")) {
predicates.add(criteriaBuilder.like(clientRoot.get(Clients_.opener), "%" + criteria.getOpener() + "%"));
}
if (!criteria.getCloser1().equalsIgnoreCase("all")) {
predicates.add(criteriaBuilder.like(clientRoot.get(Clients_.closer1), "%" + criteria.getCloser1() + "%"));
}
if (!criteria.getStatus().equalsIgnoreCase("all")) {
predicates.add(criteriaBuilder.like(clientRoot.get(Clients_.status), "%" + criteria.getStatus() + "%"));
}
clientCriteriaQuery.where(predicates.toArray(new Predicate[0]));
List<Clients> clients = em.createQuery(clientCriteriaQuery).getResultList();
return clients;
}
There's probably no substantive difference (?) from what Heiner answered. JPA and JPQL are a bit murky. I can't believe it, but I almost prefer SQL! I'll have to adjust.
I have a couple test functions I've written to illustrate a problem (or at least some behavior that I don't understand). I am just doing some basic CMIS queries on an Alfresco 4.2.e community repository, but am getting some unexpected results depending on whether I use session.query() or session.queryObjects(). Specifically, the queryObjects doesn't return properties for custom aspects. Both return the relationships/associations fine. Am I doing something wrong, or is this a bug? I'm using opencmis 0.10, and the CMIS 1.1 URL.
private static Collection<Document> testCmisObjectQuery(Session session) {
List<Document> rv = new LinkedList<>();
OperationContext opCon = session.createOperationContext();
opCon.setLoadSecondaryTypeProperties(true);
opCon.setIncludeRelationships(IncludeRelationships.BOTH);
ItemIterable<CmisObject> cmisObjs =
session.queryObjects("D:af:insuringFormInstance", null, false, opCon);
for (CmisObject o : cmisObjs) {
Document d = (Document) o;
rv.add(d);
printDocProps(d);
}
return rv;
}
private static Collection<Document> testCmisQuery(Session session) {
List<Document> rv = new LinkedList<>();
String queryString = "SELECT cmis:objectId FROM af:insuringFormInstance";
OperationContext opCon = session.createOperationContext();
opCon.setIncludeRelationships(IncludeRelationships.SOURCE);
ItemIterable<QueryResult> results = session.query(queryString, false);
for (QueryResult qResult : results) {
String objectId = qResult.getPropertyValueByQueryName("cmis:objectId");
Document doc = (Document) session.getObject(session.createObjectId(objectId),opCon);
printDocProps(doc);
rv.add(doc);
}
return rv;
}
Looks like, you are missing a join as in
select d.*, o.* from cmis:document as d join cm:ownable as o on d.cmis:objectId = o.cmis:objectId
Have a look at https://wiki.alfresco.com/wiki/CMIS#Aspect_Query for further details.
I would like to do this but with the criteria API instead:
select count(distinct e) from Event e, IN(e.userAccessPermissions) p where p.principal = :principal and p.permission in (:permissions)
Any ideas?
You can use countDistinct on CriteriaBuilder
criteriaQuery.select(criteriaBuilder.countDistinct(entityRoot))
Use c.distinct(true) on your Query.
See http://relation.to/Bloggers/ATypesafeCriteriaQueryAPIForJPA for more samples.
Like this?
Criteria crit = session.createCriteria(Event.class):
crit.createAlias("userAccessPermissions", "p");
crit.add(Restrictions.eq("p.principal", principal);
crit.add(Restrictions.in("p.permission", permissions);
crit.setProjection(Projections.countDistinct("id"));
public long getCount(String xValue){
EntityManager entityManager = this.getEntityManager();
CriteriaBuilder cb = entityManager.getCriteriaBuilder();
CriteriaQuery<Long> criteriaQuery = cb.createQuery(Long.class);
Root<MyEntity> root = criteriaQuery.from(MyEntity.class);
criteriaQuery.select(cb.count(criteriaQuery.from(MyEntity.class)));
List<Predicate> predicates = new ArrayList<>();
Predicate xEquals = cb.equal(root.get("x"), xValue);
predicates.add(xEquals);
criteriaQuery.select(cb.countDistinct(root));
criteriaQuery.where(predicates.toArray(new Predicate[0]));
return entityManager.createQuery(criteriaQuery).getSingleResult();
}
With Spring Data Jpa, we can use this method:
/*
* (non-Javadoc)
* #see org.springframework.data.jpa.repository.JpaSpecificationExecutor#count(org.springframework.data.jpa.domain.Specification)
*/
#Override
public long count(#Nullable Specification<T> spec) {
return executeCountQuery(getCountQuery(spec, getDomainClass()));
}