JpaSort using 'nulls last' with Spring Data - spring-data

How do I use JpaSort in Spring Data to return nulls last?
I currently use this kind of construct for my sorting:
new JpaSort( JpaSort.path( Datasheet_.componentSubtype )
.dot( ComponentSubtype_.componentType )
.dot( ComponentType_.name ) )
.and( new JpaSort( JpaSort.path( Datasheet_.componentSubtype )
.dot( ComponentSubtype_.name ) ) )
I saw in this answer that the Hibernate critaria API does allow it, but would like to use JPA.

The short answer is: you can't, as JPA (read: neither Criteria API nor JPQL) doesn't define means to define the sort ordering for nulls.
You might wanna look into using Querydsl as an alternative as our matching abstraction exposes the necessary API to define this. Note however, Querydsl uses persistence provider specific extensions to the JPQL generated

If you are using Spring Data Pageable in Spring MVC controller in this way
#RequestMapping(method = RequestMethod.GET)
public Page<Address> list(Pageable pageable) {...}
And you are using MySql, these URL params might help
?page=0&size=100&sort=isnull(streetLine2)&sort=streetLine2,desc

Related

Spring JPA findByColumnNameLike not working

I have a method -> findByfileNameLike(fileName,1, pageable) and its declaration in a repository that extends JPA Repository is
#Query(value = QUERY)
#Transactional(propagation = Propagation.REQUIRED, readOnly = true)
#LogExecutionTime
Page<BatchDTO> findByfileNameLike(String
fileName,#Param("departmentId")Integer departmentId, Pageable pageable)
Query is Select new DTO(bdm.id.batch.status) from Table bdm where bdm.id.departmentId =:departmentId and bdm.id.batch.status <> 7";
I want to filter the query by the column fileName.I have read to give the method name as given according to the doc of spring data jpa.But its not working.
Where and how will i give the fileName to be filtered?Should it be first parameter in the method?
Once you specify a query using the annotation #Query, Spring data jpa will not automatically create a query for you based on the method name and it will rely on the query provided by using the annotation.
The method findByfileNameLike will not make any difference here as a query is provided explicitly. Hope that answers your question

Spring JPA findBy accent

I am developing a spring-data-jpa application.
I 've ridden the repository with findBy but does not work when I look content with an accent. Does anyone know why?
I am using the following:
Page<Dades> findByNomcomercialIgnoreCaseContaining (#Param ("nomcom") String nomcom, Pageable pageable);
The database is Oracle.
Thanks for your interest.
It's because ignoreCase does not deal with accents. It only compares both String after uppercasing them. See the documentation for more informations.
I don't know any simple solution to ignore accents with Spring Jpa. You coud either :
Remove this parameter in your query, and filter the result in Java afterward (comparing Strings after doing org.apache.commons.lang3.StringUtils.stripAccents).
Use Spring Jpa Specifications. Again, it provides only functionslike upper, like, ... so you have to write your own, depending on what database you are using.
#Param is not required. if you have any query i.e if you are using #Query then we need use #param to pass the specific value releated to query.Below you can check how to use #Query and #Param
#Query("SELECT t.title FROM Todo t where t.id = :id")
String findTitleById(#Param("id") Long id);
if you are not added these annotation use in your repository layer
#Transactional
#Repository
Check another thing i.e
#Transactional
#Repository
public interface IXyzRepository extends CrudRepository<ABC,Integer>{
//some methods you have
}
whether the primary id of class ABC is of type Integer

Writing custom n1ql queries in spring

I'm trying to query a spring-data couchbase repository using N1QL queries. I have two doubts:
I'm using #Query annotation to generate queries, my code looks like this:
#Query("#{#n1ql.selectEntity} WHERE $0 = $1 AND #{#n1ql.filter}")
public Page<GsJsonStore> matchJson(String term, String value, Pageable pageable);
//Query
Page<GsJsonStore> p = repo.matchJson("_object.details.status", "ready", pg);
This query doesn't return any results. However, when I run the same query (below) in cbq I get the desired result:
select * from default where _object.details.status = 'ready';
How can I view the query string generated by the Couchbase repository? I'm using spring-boot. Am I correct in using the #Query annotation for this use-case?
Also, how can I perform n1QL queries on CouchbaseOperations template? I know that there's a findByN1QL method, but I didn't find any good documentation about it. Could someone please explain how to use this?
The query looks ok. You did persist your GsJsonStore entities using the Spring Data Couchbase repository did you?
In order to log all the queries generated and executed by the framework (including inline queries like in your case), you can configure the logger like so in a logback.xml configuration:
<logger name="org.springframework.data.couchbase.repository.query" level="debug"/>
You'll see that the query that got executed and the query that you ran in cbq are not the same, since at least you didn't use a WHERE clause.
In CouchbaseOperations there are two methods relative to N1QL queries:
findByN1QL: this expects specific structure of the query, in order to make sure all data necessary to correct deserialization of a Spring Data annotated entity is selected (which is the purpose of the #n1ql.selectEntity and #n1ql.filter SpEL).
findByN1QLProjection is more free-form. If Jackson can deserialize the results of the provided query to the requested Class, then it will. As such, the SELECT clause is much less implicitly restricted in this method.
To use both, you must pass in a N1qlQuery object from the SDK. Such queries can be constructed using factory methods of the N1qlQuery class, for example:
//a version of the query that is constructed from positional parameters
N1qlQuery queryWithParameter = N1qlQuery.parameterized("SELECT name FROM `beer-sample` WHERE name LIKE $0", JsonArray.from("%dog%"));
//let Spring Data execute the query, projecting to the String class
List<String> beerNamesContainingDog = template.findByN1QLProjection(queryWithParameter, String.class);

Spring LDAP JPA - Limit number of result

I'm using spring-ldap 2.0.4 and spring-data-jpa 1.9.0.
I built a JPA repository like this :
public interface PersonRepo extends LdapRepository<Person> {
Person findByUid (String uid);
#Query("(&(attribute=*{0}*)(attribute2=X)(attribute3=Y))")
List<Person> findByAttributeContains(String attribute);
}
So far everything is fine. I could write methods that fill my needs thanks to query methods.
For some queries i had to use #Query annotation because they were many and operator.
But i would like to limit the number of result to return from my second query method.
I know there is there is the Top and First keywords to define query methods in spring JPA. But I didn't manage to get it work. Plus I want to use multiple and operator in the method.
Thanks
I managed to limit the number of result using XML LDAP configuration.
<ldap:ldap-template context-source-ref="contextSource" count-limit="100"/>

Adding OrderBy clause to a named query

Is it possible to add an OrderBy clause in to JPA Named query at runtime?
Named queries are processed by the persistence provider when the EntityManagerFactory is created. You can't change/modify/append anything about a named query dynamically at runtime.
If you are using JPA 2.0 and you need a way to do high-performance dynamic queries at runtime, you should look into the Criteria API.
From Java EE 5 Documentation : "Is used to specify a named query in the Java Persistence query language, which is a static query expressed in metadata. Query names are scoped to the persistence unit".
As it says, it is static & you can't change the query at runtime.
Rather use custom query or if ordering element is fixed then you can use annotation;
Field:
#OrderBy(value="nickname")
List<Person> friends;
Method:
#OrderBy("nickname ASC")
public List<Person> getFriends() {...};
Even if you can't add order-by clause to your named query, you can provide a parametric orderBy. The following is a perfectly valid query:
SELECT u FROM User u ORDER BY :orderBy
And you are going to change ordering with something like:
query.setParameter("orderBy", "id");