I've been researching a while about how can I implement an Inner Join using CriteriaBuilder, but the thing is that one of the arguments which both tables have in commons is located inside a jsonb column, so the question is:
How can I INNER JOIN 2 tables by an argument that is located inside a jsonb column called "data" with criteria?
I'll drop down the example code of what I currently have.
public final CriteriaQuery<TutenBookingMacarena> createRatedBookings(
MacarenaBookingSearchFilter filters,
Integer page,
Integer pageSize,
Security security
) {
final CriteriaBuilder builder = entityManager.getCriteriaBuilder();
final CriteriaQuery<TutenBookingMacarena> criteria = builder.createQuery(TutenBookingMacarena.class);
final Root<TutenBookingMacarena> root_Booking = criteria.from(TutenBookingMacarena.class);
Join<TutenBookingMacarena, TutenCaseMacarena> rootJoin = root_Booking.join(String.valueOf(
builder.function("jsonb_extract_path_text",
String.class,
root_Booking.<String>get("data"),
builder.literal("caseId")
)
));
...
}
But when executing those lines of code I get an error message that says the named attribute can not be found. Any idea what's wrong here?
Related
I am using criteria API to create my query. Because of special sorting algorithm I use an "order by case" expression. My Unit-Tests using in memory H2 DB and are working. In the development stage we are using Oracle DB and there I get an "SQLException: ORA-12704" when executing the query.
Assume my root entity 'Foo' has a Set of 'Bar's. Bar has an attribute 'myOrderByColumn'
public class Bar {
...
#NotBlank
#javax.validation.constraints.Size(max = 255)
#Column(name = "MYORDERBYCOL")
private java.lang.String myOrderByColumn;
...
}
Here is the code which produces the exception. It creates the Order object later used in CriteriaQuery.orderBy(..)
private Order buildOrderBy(final CriteriaBuilder cb,
final Root<Foo> rootEntity,
final List<String> somehowSpecialOrderedList) {
final Expression<String> orderByColumn =
rootEntity.join(Foo_.bars, JoinType.LEFT).get(Bars.myOrderByColumn);
CriteriaBuilder.SimpleCase<String, Integer> caseRoot = cb.selectCase(orderByColumn);
IntStream.range(0, somehowSpecialOrderedList.size())
.forEach(i -> caseRoot.when(somehowSpecialOrderedList.get(i), i));
final Expression<Integer> selectCase = caseRoot.otherwise(Integer.MAX_VALUE);
return cb.asc(selectCase);
}
I took a look into the Oracle DB. The type of the column 'myOrderByColumn' ist NVARCHAR2(255).
I guess the problem here ist that the "when" part in the SQL query must match with the type of the 'MYORDERBYCOL' database column, which is NVARCHAR2. In Java I use Strings. Probably Hibernate is not casting this correctly!?
I can produce the database ORA-12704 error by
SELECT FOO.id
FROM FOO
LEFT OUTER JOIN BAR ON FOO.id = BAR.fk_id
ORDER BY
CASE FOO.myorderbycol
WHEN '20' THEN 1
ELSE 2
END ASC;
This SQL works
SELECT FOO.id
FROM FOO
LEFT OUTER JOIN BAR ON FOO.id = BAR.fk_id
ORDER BY
CASE FOO.myorderbycol
WHEN cast('20' as NVARCHAR2(255))
THEN 1ELSE 2
END ASC;
How do I have to adjust my oder by case expression with criteria API so that the query is working with any database? (must later work with at least H2, Oracle, MS SQL, PostgreSQL)
Looks like an Oracle issue to me. Which version are you using? You can try a different approach which might work.
CriteriaBuilder.SearchedCase<Integer> caseRoot = cb.selectCase();
IntStream.range(0, somehowSpecialOrderedList.size())
.forEach(i -> caseRoot.when(cb.equal(orderByColumn, somehowSpecialOrderedList.get(i)), i));
final Expression<Integer> selectCase = caseRoot.otherwise(Integer.MAX_VALUE);
I'm trying to create a criteria to retrieve Rows from 2 tables (UserDetail, Vehicle). A UserDetail has reference to Vehicle. My objective is to retrieve a list of specified field from both Tables, given an UserDetail id. In #Query was easy to do but the client said that this must be coded with criteria with specification and predicate to Join Tables.
My #Query was:
#Repository
public interface UserDao extends CrudRepository<UserDetail, Integer>{
#Query("SELECT ud.userId, ud.userName ,vh.vehicleId, vh.vehicleName "
+ "FROM UserDetail ud LEFT JOIN ud.vehicle vh where ud.vehicleId = vh.vehicleId")
public List<UserVehicleDTO> findAllUserVehicle();
}
Can anyone help me? I Fetch Data Using Specification with predicate as given Query is needed
Criteria query(I did not tested/debugged it, may need modify):
CriteriaBuilder cb = entityManager.getCriteriaBuilder();
CriteriaQuery<Tuple> query = cb.createTupleQuery();
Root<UserDetail> root = query.from(UserDetail.class);
Join<UserDetail, Vehicle> join = root.join("vehicle", JoinType.LEFT);
query.multiselect(
root.get("userId"),
root.get("userName"),
join.get("vehicleId"),
join.get("vehicleName")
))
List<Tuple> x = entityManager.createQuery(query).getResultList();
BTW. JPQL query is wrong. Don't need where condition, it will be created by JPA automatically.
SELECT ud.userId, ud.userName ,vh.vehicleId, vh.vehicleName
FROM UserDetail ud
LEFT JOIN ud.vehicle
I'm writing custom query using projection to reduce amount of queries in one session, when couple of field from antity are needed and using Fetch join.
Unfortunately got stuck into a problem when one types in returned dto is a collection.
I have following class with #ElementCollection (siplified version for this purpose):
#Entity
class MyClass(
val someString: String,
#ElementCollection
#Enumerated(EnumType.STRING)
var enums: MutableSet<Enum>,
#ManyToOne
var condition: Condition
//And so on...
)
And DTO used for projection:
data class ProjectionDTO(
val aString: String,
val enumList: List<Enum>
)
But when using query:
fun query(condition: Condition): List<ProjectionDTO> =
entityManager.createQuery(
"""SELECT NEW com.xxx.ProjectionDTO( m.someString, e ) FROM MyClass m
INNER JOIN FETCH m.enums e
WHERE m.condition = :condition""", ProjectionDTO::class.java)
.setParameter("condition", condition)
.resultList
}
I get following exception:
Exception:[org.hibernate.hql.internal.ast.QuerySyntaxException: Unable to locate appropriate constructor on class [com.xxx.ProjectionDTO]. Expected arguments are: com.xxx.String, com.xxx.Enum [SELECT NEW com.xxx.ProjectionDTO( m.someString, e ) FROM MyClass m
INNER JOIN FETCH m.enums e
WHERE m.condition = :condition]]
Already tried different types of collection, additional constructors and calling field of given #ElementCollection like e.enum in query params.
Is it possible to return a list (or other collection) from this kind of query? If so, how do I tackle it?
It is not allowed to use collection path expressions in constructor query. link
Put just root entity into constructor:
SELECT NEW com.xxx.ProjectionDTO(m) WHERE m.condition = :condition
In constructor assign m.enums, m.someString to fields.
I have following issue. I am using Jquery Datatable serverside and I am now implementing the search box. But I have an issue there in special case, when a dataset has an attribute, what is "null". So the dataset will not be found although it should found cos it matches on one attibute.
The situtation in beginning is like follows. You see there is a dataset with apprentice Fabio Bartels, who has not Fachrichtung. And a dataset with Viktoria.
Now when I search for Viktoria, the filter works as expected:
When I search for Fabio, then Dataset is not found:
=====
The problem I have is, that I don't know how to handle the filter, that a attribute will only be validated against the search string when the attribute is not null.
=====
Serverside Java Classes see like follows:
QueryClass:
class ContractSearchQuery {
private static QContract contract = QContract.contract;
static BooleanExpression getPredicate(final ContractSearch filter) {
BooleanExpression predicate;
if (filter == null || filter.isEmpty()) {
// SHOW ALL PREDICATE ...
} else {
final String search = filter.getSearch();
final List<BooleanExpression> expressions = new ArrayList<BooleanExpression>();
// EXPRESSIONS CURRENTLY ONLY ON AUSZUBILDENDER AND FACHRICHTUNG
// FOR SHOWCASE
expressions.add(containsApprenticeName(search)); // AUSZUBILDENDER
expressions.add(containsSpecialisation(search)); // FACHRICHTUNG
BooleanExpression expression = expressions.get(INTEGER_ZERO);
for (int i = 1; i < expressions.size(); i++) {
expression = expression.or(expressions.get(i));
}
predicate = expression;
}
return predicate;
}
private static BooleanExpression containsApprenticeName(final String search) {
final BooleanExpression expLastName = contract.apprentice.lastName.containsIgnoreCase(search);
final BooleanExpression expFirstName = contract.apprentice.firstName.containsIgnoreCase(search);
return expLastName.or(expFirstName);
}
private static BooleanExpression containsSpecialisation(final String search) {
return contract.companyOccupationCombination.occupationCombination.specialisation.name.containsIgnoreCase(search);
}
}
Spring-Data-Repository Call:
final PageRequest pageRequest = new PageRequest(firstResult / maxResults, maxResults, orderSort);
final Page<Contract> page = contractRepository.findAll(predicate, pageRequest);
return page.getContent();
=======
Database:
By the way I recognized when I do direct request against my db with joining Specialisation Table, then I only get Fabio as record, when not joining Specialisation, I get all three persons. Maybe somethings to do with my issue:
select a.first_name, a.last_name from contract c
join company_occupation_combination coc on c.company_occupation_combination = coc.id
join occupation_combination oc on coc.occupation_combination = oc.id
join apprentice a on c.apprentice = a.id
Result:
"Fabio";"Bartels"
"Viktoria";"Kruczek"
"Lina";"Ehleiter"
With Join:
select a.first_name, a.last_name from contract c
join company_occupation_combination coc on c.company_occupation_combination = coc.id
join occupation_combination oc on coc.occupation_combination = oc.id
join specialisation s on oc.specialisation = s.id
join apprentice a on c.apprentice = a.id
Result: "Viktoria";"Kruczek"
====
EDIT:
Okay, on db site I found out (with Hibernate and JPA I start forgetting SQL-Basices ;-)), that I need a left join for the nullable relation, so my query should result to an sql like:
select a.first_name, a.last_name from contract c
join company_occupation_combination coc on c.company_occupation_combination = coc.id
join occupation_combination oc on coc.occupation_combination = oc.id
left join specialisation s on oc.specialisation = s.id
join apprentice a on c.apprentice = a.id
====
So my question is, how can I manage left Join when I have a Query-Class using QueryDSL and Spring-Data-Repository like mentioned above?
If you really need left join, you can't achieve that via predicate (instead it is possible via sub-query)
To be able to do left-join, you will need JPAQuery.
Assuming you have already configured repositories, and able to use EntitiManager, implement ContractRepositoryCustom , so that in your implementation you can have
#PersistenceContext(unitName = "unitname")
protected EntityManager entityManager;
public List<Contract> findAllContracts() {
return new JPAQuery(entityManager, HQLTemplates.DEFAULT)
.from(QContract.contract)
.join(QContract.contract.companyOccupationCombination, QCompanyOccupationCombination.companyOccupationCombination)
.join(QCompanyOccupationCombination.companyOccupationCombination.occupationCombination, QOccupationCombination.occupationCombination)
.leftJoin(QOccupationCombination.occupationCombination.specialization, QSpecialization.specialization)
.join(QSpecialization.specialization.apprentice, QApprentice.apprentice)
.list(QContract.contract);
}
And for pagination you always apply limit(maxResults) and offset(firstResult)
I really like working with Spring-Data and Query-DSL, cos it makes my code really tidy. But I am really suprised, that for the case of nullable references there seems no solution. Sure you can use another solution like #vtorosyan mentioned and thank you again for that solution, but when you project is builded up with combination of QueryDSL and Spring-Data, you really don't want to bring a second style in your application.
But I needed a solution, so I did now the follows.
The point of the issue was, that when I used data from a nullable entity, a join has been executed what hided the datasets, who had a null reference on it, see examples above. What I now did and I hope I will not get another issue then with that solution on later time of that project. I did the null references to not null and defined something like null-record.
Example I added a record for specialisation like
ID NAME
0 Keine
Instead of null I now use that record what has until now following effects:
First my table shows now "Keine" (engl. "None") for all attributes what are not set. It looks more consistent when having a textoutput then empty string.
Now I can explicitly search for "Keine", when I am interested for data records what have no specialisation set.
And my searchbox works as expected for records, which have no speciafication set. (THAT WAS MY ISSUE FROM BEGINNING WHAT I WANTED TO SOLVE):
Additional to that searchbox I use a modal dialog for filtering. Now I can explicitly filter "Keine" for "nullable" records:
If you think there is another good solution for that issue without rebuild code using Spring-Data and QueryDSL konsequently, don't hesitate to post ;-)
Spring-data, Oliver Gierke's excellent library, has something called a Specification (org.springframework.data.jpa.domain.Specification). With it you can generate several predicates to narrow your criteria for searching.
Can someone provide an example of using a Subquery from within a Specification?
I have an object graph and the search criteria can get pretty hairy. I would like to use a Specification to help with the narrowing of the search, but I need to use a Subquery to see if some of the sub-elements (within a collection) in the object graph meet the needs of my search.
Thanks in advance.
String projectName = "project1";
List<Employee> result = employeeRepository.findAll(
new Specification<Employee>() {
#Override
public Predicate toPredicate(Root<Employee> root, CriteriaQuery<?> query, CriteriaBuilder cb) {
Subquery<Employee> sq = query.subquery(Employee.class);
Root<Project> project = sq.from(Project.class);
Join<Project, Employee> sqEmp = project.join("employees");
sq.select(sqEmp).where(cb.equal(project.get("name"),
cb.parameter(String.class, projectName)));
return cb.in(root).value(sq);
}
}
);
is the equivalent of the following jpql query:
SELECT e FROM Employee e WHERE e IN (
SELECT emp FROM Project p JOIN p.employees emp WHERE p.name = :projectName
)