I have the following entity class where objectId is alphanumeric string
#Data
#Entity
#Table(name = "CASE_INFO")
public class CaseInfo {
#Id
#Column(name = "ID")
private UUID id;
#Column(name = "OBJECT_ID")
private String objectId;
}
I also have the following repository
#Repository
public interface CaseInfoRepository extends JpaRepository<CaseInfo, UUID>, JpaSpecificationExecutor<CaseInfo> { }
Now when I make a query based on Specification and Pageable objects like this
Specification<CaseInfo> specification = (Specification<CaseInfo>) (root, query, criteriaBuilder) -> criteriaBuilder.and();
Pageable pageable = PageRequest.of(0, 25, Sort.by("objectId"));
caseInfoRepository.findAll(specification, pageable);
I want to be able to sort result based on CaseInfo.objectId numerically so that the order by in sql query would look something like this
... order by to_number(OBJECT_ID) ...
If I do something like
PageRequest.of(0, 25, Sort.by("objectId"))
it orders alphabetically so that "100" is before "2" which is wrong for my use case.
I found https://www.baeldung.com/spring-data-jpa-query where it uses
JpaSort.unsafe("LENGTH(name)")
but this does not seem to work because if I do
PageRequest.of(0, 25, JpaSort.unsafe("to_number(objectId)"))
It gives error message "No property to found for type CaseInfo! Did you mean 'id'?"
Does anybody know a way to give custom expression to Sort object?
You could add a formula field casting the string value to the numeric one and then sort by this field or use default implementation findAll(Pageable pageable):
#Data
#Entity
#Table(name = "CASE_INFO")
public class CaseInfo {
#Id
#Column(name = "ID")
private UUID id;
#Column(name = "OBJECT_ID")
private String objectId;
#Formula(value = "CAST(OBJECT_ID AS NUMERIC(10, 0))")
private int numObjectId;
}
Repository:
#Repository
public interface CaseInfoRepository extends
JpaRepository<CaseInfo, UUID>, JpaSpecificationExecutor<CaseInfo> {
// sort by formula field
List<CaseInfo> findAllByOrderByNumObjectId(Pageable pageable);
}
There is a trick with using CAST function in #Formula -- it is very likely to fail when casting to INT, INTEGER, BIGINT but it works when casting to NUMERIC(10, 0).
Numeric also should be large enough to contain the value within the string after cast otherwise an integer overflow may occur.
I am using Spring JPA to perform all database operations. However I don't know how to select specific columns from a table in Spring JPA?
For example:
SELECT projectId, projectName FROM projects
You can use projections from Spring Data JPA (doc). In your case, create interface:
interface ProjectIdAndName{
String getId();
String getName();
}
and add following method to your repository
List<ProjectIdAndName> findAll();
I don't like the syntax particularly (it looks a little bit hacky...) but this is the most elegant solution I was able to find (it uses a custom JPQL query in the JPA repository class):
#Query("select new com.foo.bar.entity.Document(d.docId, d.filename) from Document d where d.filterCol = ?1")
List<Document> findDocumentsForListing(String filterValue);
Then of course, you just have to provide a constructor for Document that accepts docId & filename as constructor args.
You can set nativeQuery = true in the #Query annotation from a Repository class like this:
public static final String FIND_PROJECTS = "SELECT projectId, projectName FROM projects";
#Query(value = FIND_PROJECTS, nativeQuery = true)
public List<Object[]> findProjects();
Note that you will have to do the mapping yourself though. It's probably easier to just use the regular mapped lookup like this unless you really only need those two values:
public List<Project> findAll()
It's probably worth looking at the Spring data docs as well.
In my situation, I only need the json result, and this works for me:
public interface SchoolRepository extends JpaRepository<School,Integer> {
#Query("select s.id, s.name from School s")
List<Object> getSchoolIdAndName();
}
in Controller:
#Autowired
private SchoolRepository schoolRepository;
#ResponseBody
#RequestMapping("getschoolidandname.do")
public List<Object> getSchool() {
List<Object> schools = schoolRepository.getSchoolIdAndName();
return schools;
}
With the newer Spring versions One can do as follows:
If not using native query this can done as below:
public interface ProjectMini {
String getProjectId();
String getProjectName();
}
public interface ProjectRepository extends JpaRepository<Project, String> {
#Query("SELECT p FROM Project p")
List<ProjectMini> findAllProjectsMini();
}
Using native query the same can be done as below:
public interface ProjectRepository extends JpaRepository<Project, String> {
#Query(value = "SELECT projectId, projectName FROM project", nativeQuery = true)
List<ProjectMini> findAllProjectsMini();
}
For detail check the docs
In my case i created a separate entity class without the fields that are not required (only with the fields that are required).
Map the entity to the same table.
Now when all the columns are required i use the old entity, when only some columns are required, i use the lite entity.
e.g.
#Entity
#Table(name = "user")
Class User{
#Column(name = "id", unique=true, nullable=false)
int id;
#Column(name = "name", nullable=false)
String name;
#Column(name = "address", nullable=false)
Address address;
}
You can create something like :
#Entity
#Table(name = "user")
Class UserLite{
#Column(name = "id", unique=true, nullable=false)
int id;
#Column(name = "name", nullable=false)
String name;
}
This works when you know the columns to fetch (and this is not going to change).
won't work if you need to dynamically decide the columns.
In my opinion this is great solution:
interface PersonRepository extends Repository<Person, UUID> {
<T> Collection<T> findByLastname(String lastname, Class<T> type);
}
and using it like so
void someMethod(PersonRepository people) {
Collection<Person> aggregates =
people.findByLastname("Matthews", Person.class);
Collection<NamesOnly> aggregates =
people.findByLastname("Matthews", NamesOnly.class);
}
I guess the easy way may be is using QueryDSL, that comes with the Spring-Data.
Using to your question the answer can be
JPAQuery query = new JPAQuery(entityManager);
List<Tuple> result = query.from(projects).list(project.projectId, project.projectName);
for (Tuple row : result) {
System.out.println("project ID " + row.get(project.projectId));
System.out.println("project Name " + row.get(project.projectName));
}}
The entity manager can be Autowired and you always will work with object and clases without use *QL language.
As you can see in the link the last choice seems, almost for me, more elegant, that is, using DTO for store the result. Apply to your example that will be:
JPAQuery query = new JPAQuery(entityManager);
QProject project = QProject.project;
List<ProjectDTO> dtos = query.from(project).list(new QProjectDTO(project.projectId, project.projectName));
Defining ProjectDTO as:
class ProjectDTO {
private long id;
private String name;
#QueryProjection
public ProjectDTO(long projectId, String projectName){
this.id = projectId;
this.name = projectName;
}
public String getProjectId(){ ... }
public String getProjectName(){....}
}
Using Spring Data JPA there is a provision to select specific columns from database
---- In DAOImpl ----
#Override
#Transactional
public List<Employee> getAllEmployee() throws Exception {
LOGGER.info("Inside getAllEmployee");
List<Employee> empList = empRepo.getNameAndCityOnly();
return empList;
}
---- In Repo ----
public interface EmployeeRepository extends CrudRepository<Employee,Integer> {
#Query("select e.name, e.city from Employee e" )
List<Employee> getNameAndCityOnly();
}
It worked 100% in my case.
Thanks.
You can use JPQL:
TypedQuery <Object[]> query = em.createQuery(
"SELECT p.projectId, p.projectName FROM projects AS p", Object[].class);
List<Object[]> results = query.getResultList();
or you can use native sql query.
Query query = em.createNativeQuery("sql statement");
List<Object[]> results = query.getResultList();
You can apply the below code in your repository interface class.
entityname means your database table name like projects.
And List means Project is Entity class in your Projects.
#Query(value="select p from #{#entityName} p where p.id=:projectId and p.projectName=:projectName")
List<Project> findAll(#Param("projectId") int projectId, #Param("projectName") String projectName);
It is possible to specify null as field value in native sql.
#Query(value = "select p.id, p.uid, p.title, null as documentation, p.ptype " +
" from projects p " +
"where p.uid = (:uid)" +
" and p.ptype = 'P'", nativeQuery = true)
Project findInfoByUid(#Param("uid") String uid);
You can use the answer suggested by #jombie, and:
place the interface in a separate file, outside the entity class;
use native query or not (the choice depended on your needs);
don't override findAll() method for this purpose but use name of your choice;
remember to return a List parametrized with your new interface (e.g. List<SmallProject>).
Using Native Query:
Query query = entityManager.createNativeQuery("SELECT projectId, projectName FROM projects");
List result = query.getResultList();
public static final String FIND_PROJECTS = "select ac_year_id,ac_year from tbl_au_academic_year where ac_year_id=?1";
#Query(value = FIND_PROJECTS, nativeQuery = true)
public List<Object[]> findByAcYearId(Integer ac_year_id);
this works for me
You can update your JPARepository as below.
#Query("select u.status from UserLogin u where u.userId = ?1 or u.email = ?1 or u.mobile = ?1")
public UserStatus findByUserIdOrEmailOrMobile(String loginId);
Where UserStatus is a Enum
public enum UserStatus
{
New,
Active,
Deactived,
Suspended,
Locked
}
Use:
#Query("SELECT e FROM #{#entityName} e where e.userId=:uid")
List<ClienteEnderecoEntity> findInfoByUid(#Param("uid") UUID uid);
{
"Comments":"Why not using JDBCTemplate",
"Url":"https://www.baeldung.com/spring-jdbc-jdbctemplate"
}
How it is possible to use arbitrary sql query (I mean native sql query) in some repository? My actual problem is this:
#Data //lombok thing
#Entity
public class A extends AuditModel {
private long id;
private String name;
#OneToMany(mappedBy="a") //Comments.a is owning side of association, i.e. comments table does have column called a_id as foreign key
#ToString.Exclude
private Set<Comments> comments = new HashSet();
#OneToMany(mappedBy="a") //SimpleFile.a is owning side of association
private Set<SimpleFile> comments = new HashSet();
}
Than I have my repository, which exposes nice crud interface using HAL+json representation. I am trying to enrich it with some projection/view particularly due to web UI to load one page data in single request. I am aware of excerps and projections, but they seems not to be enough powerful.
#Repository
#RepositoryRestResource
#Transactional(readOnly = true)
public interface ARepository extends PagingAndSortingRepository<A, Long> {
Page<A> findByNameContaining(String namePart, Pageable pageable);
#Query(
value = "SELECT a.name,\n" +
"(SELECT CAST(count(ac.id) AS int) FROM COMMENTS ac WHERE ac.a_id = a.id),\n" +
"(SELECT listagg(asf.id) FROM SIMPLE_FILES asf WHERE asf.a_id = a.id)\n" +
"FROM AS a\n" +
"WHERE a.id = :id",
nativeQuery = true
)
Optional<ACustomPage42DTO> getByIdProjectedForScreen42(Long id);
}
I have also tried to use JPQL, but there I had problem with fetch join (as I am not familiar with JPQL). My last evaluation query was something like this:
#Query("SELECT new sk.qpp.qqq.documents.projections.ACustomPage42DTO(" +
"a " +
"(SELECT CAST(count(ac) AS int) FROM COMMENTS ac WHERE ac.a = a)" +
")\n" +
"FROM A a\n" +
"LEFT JOIN FETCH a.simpleFiles\n" +
"WHERE a.id = :id"
)
I would like to get some general advice about what approach is best to implement custom and complex query to be returned in DTO (ideally with some specific links to actions when needed).
PS: Implementing interface and returning simple (primitive) data works. Also using JPQL to create custom DAO instance works (with simple types and with single instance of type A for example). Method for using given query method does appear in search methods of given entity endpoint. I would like to have something more reasonable, so I would like to have projection as defined in spring data rest project.
I have my DTO object fully under my control. I prefer it to use #Value or #Data annotation from project lombok, but it is not a need. I have tried also these versions of DTO definition (using interface works for simple data and similarly class works for simple data).
interface ACustomPage42DTO {
String getName();
long getCommentsCount();
Object getAsdf();
}
Or using equivalent class with some bonus, like custom toString() method possible, or some custom getter for computed data:
#Value //lombok thing, imutable "POJO"
public class ACustomPage42DTO {
String name;
long commentsCount;
Set<SimpleFile> simpleFiles;
public ACustomPage42DTO(A a, long count) {
// constructor used by JPQL, if it works
name = a.getName();
this.commentsCount = count;
this.simpleFiles = a.getSimpleFiles(); // should be already fetched, due to fetch join in JPQL
}
}
Both working approaches can be called using "search" url, instead of projection. I see my method getByIdProjectedForScreen42 on url http://localhost:9091/api/a/search listing. I would like to use it like (I think that is the "right" way) http://localhost:8080/api/a?projection=ACustomPage42DTOProjection .
Question is quite broad and touches couple of aspects:
custom JPA repository method using #Query
selecting results in your #Query
mapping #Query results to an interface
exposing new repository method through #RepositoryRestResource
TLDR: wrote an example of what is talked about with couple of basic tests https://github.com/ivarprudnikov/test-spring-jpa-repository-query-exposed-through-http
custom JPA repository method using #Query
As you have mentioned it is quite straightforward, just annotate a method with #Query and make sure your return type corresponds to what is being returned from the query, eg:
public interface FooRepository extends JpaRepository<FooEntity, Long> {
#Query(nativeQuery = true, value = "select f from foo f where f.name = :myParam")
Optional<FooEntity> getInSomeAnotherWay(String myParam);
}
selecting results in your #Query
You have given an example already but I'll simplify to make it easier and shorter.
Given entities FooEntity.java and BarEntity.java:
#Entity
#Table(name = "foo")
public class FooEntity {
#Id
#Column(name = "id", unique = true, nullable = false)
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#Column(name = "name", nullable = false)
private String name;
#OneToMany(mappedBy = "foo")
private Set<BarEntity> bars = new HashSet<>();
// getter setters excluded for brevity
}
#Entity
#Table(name = "bar")
public class BarEntity {
#Id
#Column(name = "id", unique = true, nullable = false)
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#Column(name = "name", nullable = false)
private String name;
#ManyToOne(targetEntity = FooEntity.class)
#JoinColumn(name = "foo_id", nullable = false, foreignKey = #ForeignKey(name = "fk_bar_foo"))
private FooEntity foo;
// getter setters excluded for brevity
}
We want now to return custom result set which contains FooEntity.name and count of FooEntity.bars:
SELECT f.name as name, count(b.id) as barCount FROM foo f, bar b WHERE f.id = :id AND b.foo_id = :id
+-----------------+----------+
| name | barCount |
+-----------------+----------+
| Jonny tables | 1 |
+-----------------+----------+
mapping #Query results to an interface
To map above result set we need an interface where getters nicely reflect what is being selected:
public interface ProjectedFooResult {
String getName();
Long getBarCount();
}
Now we can rewrite our repository method to:
#Query(nativeQuery = true,
value = "SELECT f.name as name, count(b.id) as barCount FROM foo f, bar b WHERE f.id = :id AND b.foo_id = :id")
Optional<ProjectedFooResult> getByIdToProjected(Long id);
exposing new repository method through #RepositoryRestResource
I am not very familiar with this but after adding org.springframework.data:spring-data-rest-hal-browser dependency I got this nice interface that exposed available methods after repository was annotated with #RepositoryRestResource. For a given repository which contains above mentioned details:
#RepositoryRestResource(path = "foo")
public interface FooRepository extends JpaRepository<FooEntity, Long> {
#Query(nativeQuery = true, value = "SELECT f.name as name, count(b.id) as barCount FROM foo f, bar b WHERE f.id = :id AND b.foo_id = :id")
Optional<ProjectedFooResult> getByIdToProjected(Long id);
}
the method will be exposed through http://localhost:8080/foo/search/getByIdToProjected?id=1 when running locally.
As mentioned above the reference implementation is on Github https://github.com/ivarprudnikov/test-spring-jpa-repository-query-exposed-through-http
Additional helpful documentation for 'Custom Implementations for Spring Data Repositories'
So I am writing native queries because they are very complex to get all the needed data and so on. I am currently facing a problem which is normally done by Hibernate/JPA etc.
Imagine the following:
#Entity
FooEntity{
#Id
public Long id;
#ManyToMany
public List<FeeEntity> feeEntities;
}
#Entity
FeeEntity{
#Id
public Long id;
#Column
public String name;
}
And some DTO
FooDTO{
private final Long id;
private final List<FeeDTO> someStrings;
public FooDTO(Long id, List<FeeDTO> feeDtos){
...
}
}
My #SqlResultSetMapping looks basically like
#SqlResultSetMapping(name = "FooDTO",
classes = #ConstructorResult(targetClass = FooDTO.class, columns = {
#ColumnResult(name = "id", type = Long.class),
//TODO #ColumnResult(name = "feeDtos", type = FeeDtos.class)
})
)
The named native query looks something like:
#NamedNativeQueries({
#NamedNativeQuery(
name = "FooData",
query = "SELECT MAINSELECT.ID AS id, " +
"???" +
" FROM Foo MAINSELECT WHERE ... " +
...,
resultSetMapping = "FooDTO")
})
How do I have to write the native query? Is this even possible without a subquery or do I have to do/execute a subquery for each datarow of the result? I was not able to find something on beloved google.
That's not possible.
The result of SQL query is always a table. So there are no nested tables and hence you cannot map it to a Collection.
I want to create a hibernate SQL query and cast it to an object without creating the table.
for example i have
StringBuilder query = new StringBuilder();
query.append("SELECT groupId, categoryId, name FROM AssetCategory");
SQLQuery sqlQuery = session.createSQLQuery(query.toString());
sqlQuery.addEntity("Categories", Categories.class);
List<Categories> list = sqlQuery.list();
The category object is declared like this :
#Entity
public class Categories implements Serializable {
#Column(name = "name")
String name;
#Column(name = "categoryId")
Long categoryId;
#Column(name = "groupId")
Long groupId;
Of course this cant work because there is no ID. And this table does not need to be created either. So how would i go about declaring this ?
Any hints ?
I just cant find the documentation.
you can use a SQLTransformer to do this.. you wont need the annotations in the pojo even.
read this. it will help you realize what you should be doing.