I need to create a query by deciding on runtime. Basically I have few parameters and one of them will specify If I should use And or Or to combine criterias. By using Spring JPA Repository how can I do it? It is easy to do it for parameters as :
#Query(value = "SELECT u FROM User u WHERE u.name IN :names")
List<User> findUserByNameList(#Param("names") Collection<String> names);
But if I want to add one more criteria lets say size, and I need to decide which one of (AND,OR) to use to combine criteria, how can I do it?
Example:
SELECT u FROM User u WHERE u.name IN :names OR/AND size = 10;
public List<User> getUsers(List<String> names, Integer size, boolean useOrPredicate) {
CriteriaBuilder criteriaBuilder = entityManager.getCriteriaBuilder();
CriteriaQuery<User> criteriaQuery = criteriaBuilder.createQuery(User.class);
Root<User> user = criteriaQuery.from(User.class);
Predicate predicate1 = user.get("name").in(names);
Predicate predicate2 = criteriaBuilder.equal(user.get("size"), size);
Predicate predicate;
if(useOrPredicate)
predicate = criteriaBuilder.or(predicate1, predicate2);
else
predicate = criteriaBuilder.and(predicate1, predicate2);
criteriaQuery.where(predicate);
return entityManager.createQuery(criteriaQuery).getResultList();
}
Related
I want to rewrite this SQL query in JPA.
String hql = "SELECT date(created_at) AS cdate, sum(amount) AS amount, count(id) AS nooftransaction "
+ "FROM payment_transactions WHERE date(created_at)>=date(now()- interval 10 DAY) "
+ "AND date(created_at)<date(now()) GROUP BY date(created_at)";
TypedQuery<Merchants> query = entityManager.createQuery(hql, Merchants.class);
List<Merchants> merchants = query.getResultList();
Is there a way to rewrite the queries into JPA or I should use it as it is?
In situations like these, more often than not the best approach is to write a plain SQL view:
CREATE OR REPLACE VIEW payment_transactions_stats AS
SELECT date(created_at) AS cdate, sum(amount) AS amount, count(id) AS nooftransaction
FROM payment_transactions
WHERE date(created_at)>=date(now()- interval 10 DAY)
AND date(created_at)<date(now()) GROUP BY date(created_at);
And map it to an #Immutable entity. This approach works well when:
you have read only data
the view does not need parameters (in this case there are solutions as well which span from hacky to nice)
You provide no details about the classes and entities but it could be something like:
CriteriaBuilder builder = entityManager.getCriteriaBuilder();
CriteriaQuery<Tuple> query = builder.createTupleQuery();
From<PaymentTransaction> tx = query.from(PaymentTransaction.class);
Expression<Long> sumAmount = builder.sum(tx.get("amount"));
Expression<Long> count = builder.count(tx.get("id"));
Expression<Date> createdAt = tx.get("created_at");
query.multiselect(createdAt, sumAmount, count);
query.where(builder.greaterThanOrEqualTo(createdAt, builder.function("DATEADD", "DAY", new Date(), builder.literal(-10))),
builder.lessThan(createdAt, new Date()));
query.groupBy(createdAt);
entityManager.createQuery(query).getResultList().stream()
.map(t -> new Merchants(t.get(0, Date.class), t.get(1, Long.class), t.get(2, Long.class)))
.collect(Collectors.toList());
It is better not to use JPA for complex queries like this. JPA are usually used for simple queries.
Since the question is tagged with spring-data-jpa, you could try using a Spring CRUDRepository on top of your table. In the CRUDRepository, write a custom method with the #Query annotation.
It's hard for me to formulate the entire query because I don't know the members of your Merchants class.
Alternatively you can set the nativeQuery = true for the #Query annotation and use actual DB query to solve your problem.
You can use below code
CriteriaBuilder qb = entityManager.getCriteriaBuilder();
CriteriaQuery cq = qb.createQuery();
Root paymentInstructionsRoot = cq.from(PaymentInstructions.class);
List<Predicate> predicates = new ArrayList<>();
predicates.add(qb.greaterThanOrEqualTo(path, fromDateRange));
predicates.add(qb.lessThanOrEqualTo(path, toDateRange));
Selection cdate = paymentInstructionsRoot.get(PaymentInstructions_.createdAt).alias("cdate");
Selection amount = qb.sum(paymentInstructionsRoot.get(PaymentInstructions_.amount))).alias("amount");
Selection nooftransaction = qb.count(paymentInstructionsRoot.get(PaymentInstructions_.id))).alias("nooftransaction");
Selection[] selectionExpression = {cdate, amount, nooftransaction};
Expression[] groupByExpression = {paymentInstructionsRoot.get(PaymentInstructions_.createdAt)};
cq.multiselect(selectionExpression).where(predicates.toArray(new Predicate[]{})).groupBy(groupByExpression).where(predicates.toArray(new Predicate[]{}));
List<PaymentInstructions> paymentInstructions = entityManager.createQuery(cq).getResultList();
In your Entity class that represents the 'payment_transactions' table, add the following:
#SqlResultSetMapping(
name = "PaymentTransaction.summaryMapping",
classes = {
#ConstructorResult(targetClass = PaymentTransactionSummary.class,
columns = {
#ColumnResult(name = "cdate")
, #ColumnResult(name = "amount")
, #ColumnResult(name = "nooftransaction")
})
}
)
Create a new pojo class named PaymentTransactionSummary (must match the name used above, or whatever name you choose, with member fields cdate, amount, and nooftransaction. Include a constructor that includes those three fields in the order listed above.
Then in your dao class, write this:
Query q = entityManager.createNativeQuery("your query string from above"
, "PaymentTransaction.summaryMapping");
List<PaymentTransactionSummary> results = q.getResultList();
Here I am using NativeQuery to perform selecting lookup type using subquery this is working right but I want to use Criteria Builder. How can I use it?
Query query = em.createNativeQuery(
"SELECT * FROM LOOKUPMASTER WHERE PARENTLOOKUPTYPEID = (SELECT LOOKUPID FROM LOOKUPMASTER WHERE LOOKUPTYPE =? ) ",
Lookupmaster.class
);
query.setParameter(1, lookUpType);
I tried to write the above query using criteria builder but I am getting different result here is my criteria query.
CriteriaBuilder cb = em.getCriteriaBuilder();
CriteriaQuery cq = cb.createQuery(Lookupmaster.class);
Root<Lookupmaster> rt = cq.from(Lookupmaster.class);
Path<Object> path = rt.get("parentlookuptypeid");
cq.select(rt);
Subquery<Lookupmaster> subquery = cq.subquery(Lookupmaster.class);
Root rt1 = subquery.from(Lookupmaster.class);
subquery.select(rt1.get("lookupid"));
subquery.where(cb.equal(rt.get("lookuptype"),lookUpType));
cq.where(cb.in(path).value(subquery));
Query qry =em.createQuery(cq);
CriteriaBuilder criteriaBuilder = entityManager.getCriteriaBuilder();
CriteriaQuery<Object> criteriaQuery = criteriaBuilder.createQuery();
Root<EMPLOYEE> from = criteriaQuery.from(EMPLOYEE.class);
Path<Object> path = from.get("compare_field"); // field to map with sub-query
from.fetch("name");
from.fetch("id");
CriteriaQuery<Object> select = criteriaQuery.select(from);
Subquery<PROJECT> subquery = criteriaQuery.subquery(PROJECT.class);
Root fromProject = subquery.from(PROJECT.class);
subquery.select(fromProject.get("requiredColumnName")); // field to map with main-query
subquery.where(criteriaBuilder.equal("name",name_value));
subquery.where(criteriaBuilder.equal("id",id_value));
select.where(criteriaBuilder.in(path).value(subquery));
TypedQuery<Object> typedQuery = entityManager.createQuery(select);
List<Object> resultList = typedQuery.getResultList();
Here is a link
another article
I have a basic structure of 2 domain entities:
User
UserDetails
Where a User holds (has a) UserDetails, and UseDetails has String userName.
Using JPA criteria API I would like to commit a simple query which loads a User by a given user-name.
In code, I would like it to look more or less like this:
public User findByUsername(String userName) {
CriteriaBuilder qb = entityManager.getCriteriaBuilder();
CriteriaQuery<User> c = qb.createQuery(User.class);
Root<User> user = c.from(User.class);
Predicate condition = qb.equal(user.get(User_.userDetails.getuserName()), userName);
c.where(condition);
TypedQuery<User> q = entityManager.createQuery(c);
List<User> result = q.getResultList();
if (result.isEmpty()) {
return null;
}
return result.get(0);
}
But this doesn't work since getuserName() cannot be found under User_.userDetails.
I guess this is not the way to do that, maybe I need to implement a Join between those tables (User and UserDetails)?
How should I do it?
I can't try it now, but I think you must do something like:
Predicate condition = qb.equal(user.get(User_.userDetails).get(UserDetails_.userName), userName);
I'm learning jpa-hibernate basics.
I have this query for getting all users:
CriteriaBuilder cb = getEntityManager().getCriteriaBuilder();
CriteriaQuery cq = cb.createQuery();
cq.select(cq.from(Utente.class));
return getEntityManager().createQuery(cq).getResultList();
Now I want to filter by a boolean field named 'ghost' where it equals true (or false, it depends).
Translated:
SELECT * FROM users WHERE ghost = 0;
Do I have to use cq.where() ? How?
Yes, you have to use cq.where().
Try something like this:
Root<Utente> utente = cq.from(Utente.class);
boolean myCondition = true; // or false
Predicate predicate = cb.equal(utente.get(Utente_.ghost), myCondition);
cq.where(predicate);
Where I have used the canonical metamodel class Utente_ that should be generated automatically. This avoids the risk of making errors in typing field names, and enhances type safety. Otherwise you can use
Predicate predicate = cb.equal(utente.get("ghost"), myCondition);
I want to do something like this:
select count(*) from (select ...)
(As it would be in SQL), but in JPA.
Any ideas on how I would do it?
I stumbled upon this issue as well. I would ultimately like to execute the following JPQL:
SELECT COUNT(u)
FROM (
SELECT DISTINCT u
FROM User u
JOIN u.roles r
WHERE r.id IN (1)
)
But this wasn't possible, also not with criteria API. Research taught that this was just a design limitation in JPA. The JPA spec states that subqueries are only supported in WHERE and HAVING clauses (and thus not in the FROM).
Rewriting the query in the following JPQL form:
SELECT COUNT(u)
FROM User u
WHERE u IN (
SELECT DISTINCT u
FROM User u
JOIN u.roles r
WHERE r.id IN (1)
)
using the JPA Criteria API like as follows:
CriteriaQuery<Long> query = cb.createQuery(Long.class);
Root<User> u = query.from(User.class);
Subquery<User> subquery = query.subquery(User.class);
Root<User> u_ = subquery.from(User.class);
subquery.select(u_).distinct(true).where(u_.join("roles").get("id").in(Arrays.asList(1L)));
query.select(cb.count(u)).where(cb.in(u).value(subquery));
Long count = entityManager.createQuery(query).getSingleResult();
// ...
has solved the functional requirement for me. This should also give you sufficient insight into solving your particular functional requirement.
This should do the trick (If you want to use JPA criteria API):
CriteriaBuilder cb = getEntityManager().getCriteriaBuilder();
CriteriaQuery<Long> query = cb.createQuery(Long.class);
Root<Entity> root = query.from(Entity.class);
//Selecting the count
query.select(cb.count(root));
//Create your search criteria
Criteria criteria = ...
//Adding search criteria
query.where(criteria);
Long count = getEntityManager().createQuery(query).getSingleResult();
On the other hand, if you want to use JP-QL, the following code should do the trick:
//Add the where condition to the end of the query
Query query = getEntityManager().createQuery("select count(*) from Entity entity where...")
Long count = query.getSingleResult();
Use the following snippet to count rows for a given Criteria Query:
public static Query createNativeCountQuery(EntityManager em, CriteriaQuery<?> criteriaQuery) {
org.hibernate.query.Query<?> hibernateQuery = em.createQuery(criteriaQuery).unwrap(org.hibernate.query.Query.class);
String hqlQuery = hibernateQuery.getQueryString();
QueryTranslatorFactory queryTranslatorFactory = new ASTQueryTranslatorFactory();
QueryTranslator queryTranslator = queryTranslatorFactory.createQueryTranslator(
hqlQuery,
hqlQuery,
Collections.emptyMap(),
em.getEntityManagerFactory().unwrap(SessionFactoryImplementor.class),
null
);
queryTranslator.compile(Collections.emptyMap(), false);
String sqlCountQueryTemplate = "select count(*) from (%s)";
String sqlCountQuery = String.format(sqlCountQueryTemplate, queryTranslator.getSQLString());
Query nativeCountQuery = em.createNativeQuery(sqlCountQuery);
Map<Integer, Object> positionalParamBindings = getPositionalParamBindingsFromNamedParams(hibernateQuery);
positionalParamBindings.forEach(nativeCountQuery::setParameter);
return nativeCountQuery;
}
private static Map<Integer, Object> getPositionalParamBindingsFromNamedParams(org.hibernate.query.Query<?> hibernateQuery) {
Map<Integer, Object> bindings = new HashMap<>();
for (var namedParam : hibernateQuery.getParameterMetadata().getNamedParameters()) {
for (int location : namedParam.getSourceLocations()) {
bindings.put(location + 1, hibernateQuery.getParameterValue(namedParam.getName()));
}
}
return bindings;
}