I'm trying to fetch all rows that have the same patient_id, so I'm doing findAllByPatientId. But I'm always receiving one object in the Listinstead of all the rows.
#Entity
#Getter
#Setter
public class MedicalHistory extends BaseEntity {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "id")
private Long id;
#ManyToOne
#JoinColumn(name = "operator_id")
private MedicalOperator medicalOperatorId;
#ManyToOne
#JoinColumn(name = "illness_id")
private Illness illnessId;
#ManyToOne
#JoinColumn(name= "patientId")
private Patient patientId;
}
public List<MedicalHistory> getPatientMedicalRecords(PatientDto patientDto) {
Optional<Patient> getPatient = patientRepository.findByNin(patientDto.getNin());
Long patientId = getPatient.get().getPatientId();
return medicalHistoryRepository.findAllByPatientId(patientId);
}
I want to receive multiple rows using the patient_id but instead, I'm always getting one !!.
I tried native query and hibernate but nothing is working.
public interface MedicalHistoryRepository extends JpaRepository<MedicalHistory, Long> {
// List<MedicalHistory> findAllByPatientId(Long id);
ArrayList<MedicalHistory> findMedicalHistoriesByPatientId(Long id);
#Query(value = "SELECT * FROM medical_history WHERE patient_id = id",nativeQuery = true)
List<MedicalHistory> findAllByPatientId(Long id);
}
Now you are requesting "give me medical_history where id = patient_id" and getting only one result row.
You need to add a colon to the query to set a parameter to fix a result
value = "SELECT * FROM medical_history WHERE patient_id = :id"
Look for JPQL, it's java persistancy query language and spring is automatically turning your #query into it. Spring is also supporting spEL you can also have a look to it here : https://docs.spring.io/spring-data/jpa/docs/current/reference/html/#jpa.query.spel-expressions where you can see than you can grab your parameters ever with ?number or with :name or putting #Param("name") into your parameters definition. As said before there is multiple ways to receive a parameter in you query but certainly not like you previously did.
That's why you don't receive anything.
Related
I wrote native query but I'm getting an error:
The column name covidSymptomId is not valid.
What's wrong?
There are table in mssql
Error picture
CovidSymptom.java
#Data
#AllArgsConstructor
#NoArgsConstructor
#Entity
#Table(name="CovidSymptom")
public class CovidSymptom {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "covidSymptomId")
private int id;
#ManyToOne
#JoinColumn(name = "covidId")
private Covid covidSymptom;
#Column(name = "symptom")
private String symptom;
}
CovidSymptomDao.java
#Query(nativeQuery = true,value = "Select symptom From CovidSymptom GROUP BY symptom order by count(covidSymptomId) desc")
List<CovidSymptom> getMost3SymptomOffCovid();
You need to include all columns that are mapped in your query. So:
Select covidSymptomId, symptom....
I'm not sure why you're getting a column name problem, since your select query returns a list of "symptom"(String), whilst your method provides a list of "CovidSymptom" (Object).
I have an Entity called Student
#Entity
#Table(name = "students")
public class Student implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "STUDENT_ID")
private Integer studentId;
#Column(name = "STUDENT_NAME", nullable = false, length = 100)
private String studentName;
#OneToMany(fetch = FetchType.EAGER, mappedBy = "student", cascade = CascadeType.ALL)
private List<Note> studentNotes;
// Some other instance variables that are not relevant to this question
/* Getters and Setters */
}
and an entity called as Note
#Entity
#Table(name = "notes")
public class Note implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "NOTE_ID")
private Integer noteId;
#Column(name = "NOTE_CONTENT")
private String noteText;
#ManyToOne(fetch = FetchType.EAGER)
#JoinColumn(name = "STUDENT_ID")
private Student student;
/* Getters and Setters */
}
As you can see the relationship dictates that a Student can have multiple number of notes.
For displaying some information about the student on a particular page I need only the studentName, count of notes and all the notes.
I created a StudentDTO for that and it looks something like this:
public class StudentDTO {
private Long count;
private String name;
private List<Note> notes;
/* Getters and setters */
}
And I am using the following code to map the Student and Notes returned from the DB to the StudentDTO
private static void testDTO() {
Session session = getSessionFactory().openSession();
String queryString = "SELECT count(n) as count, s.studentName as name, s.studentNotes as notes " +
"from Student s join s.studentNotes n where s.id = 3";
Query query = session.createQuery(queryString);
List<StudentDTO> list = query.setResultTransformer(Transformers.aliasToBean(StudentDTO.class)).list();
for (StudentDTO u : list) {
System.out.println(u.getName());
System.out.println(u.getCount());
System.out.println(u.getNotes().size());
}
}
The above code fails when there are notes fetched in the query but if I remove the notes and get only name and count it works fine.
When notes is included in the query, this is the error that is fired by Hibernate:
select
count(studentnot2_.NOTE_ID) as col_0_0_,
. as col_3_0_,
studentnot3_.NOTE_ID as NOTE_ID1_2_,
studentnot3_.NOTE_CONTENT as NOTE_CON2_2_,
studentnot3_.STUDENT_ID as STUDENT_3_2_
from
students studentx0_
inner join
notes studentnot2_
on studentx0_.STUDENT_ID=studentnot2_.STUDENT_ID
inner join
notes studentnot3_
on studentx0_.STUDENT_ID=studentnot3_.STUDENT_ID
where
studentx0_.STUDENT_ID=3;
And this is the error message that I get:
You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'as col_3_0_, studentnot3_.NOTE_ID as NOTE_ID1_2_, studentnot3_.NOTE_CONTENT as N' at line 1
Now I can see where the query is wrong but it is generated by Hibernate, not something that I have control on. Is there something that I need to change in my queryString to acheive the result that I need.
I do not want to manually map the results to my DTO, is there a way that I can directly map my studentNotes in Student.java to notes in StudentDTO.java
Looks like this query is wrong. The better way is to get just the student. You can always get collection of notes from a student.
Session session = getSessionFactory().openSession();
String queryString = from Student s where s.studentId = 3;
Query query = session.createQuery(queryString);
Student student = query.getSingleResult();
sysout(student.getNotes().size())
Also, I never retrieved collection this way in SELECT clause; so, not sure but do you really need
join s.studentNotes
in your query? Not sure if my answer is helpful.
Your query is wrong as you would need two joins to also select the count of notes, but that's not even necessary, as you could determine the count by just using the size of the notes collection.
I created Blaze-Persistence Entity Views for exactly that use case. You essentially define DTOs for JPA entities as interfaces and apply them on a query. It supports mapping nested DTOs, collection etc., essentially everything you'd expect and on top of that, it will improve your query performance as it will generate queries fetching just the data that you actually require for the DTOs.
The entity views for your example could look like this
#EntityView(Student.class)
interface StudentDTO {
#Mapping("studentName")
String getName();
#Mapping("studentNotes")
List<NoteDTO> getNotes();
default int getCount() { return getNotes().size(); }
}
#EntityView(Note.class)
interface NoteDTO {
// attributes of Note that you need
#IdMapping Integer getId();
String getNoteText();
}
Querying could look like this
StudentDTO student = entityViewManager.find(entityManager, StudentDTO.class, studentId);
I have a simple spring boot rest app connected with mySQL db and I'm trying to optimize number of queries within simple function:
List<Message> messages = messagesRepository.findBySenderIdOrReceiverIdOrderByTimeDesc(senderId, receiverId);
MessagesRepository:
public interface MessagesRepository extends CrudRepository<Message, Long> {
List<Message> findBySenderIdOrReceiverIdOrderByTimeDesc(Long senderId, Long receiverId);
}
Message:
#Entity
#Table(name="s_messages")
public class Message implements Serializable
{
#Id
#GeneratedValue(strategy=GenerationType.AUTO)
private Long id;
#Transient
private int internalId;
#ManyToOne(fetch = FetchType.EAGER)
#JoinColumn(name="senderId", referencedColumnName = "id", updatable=false, insertable=false)
private ProfileLite sender;
#ManyToOne(fetch = FetchType.EAGER)
#JoinColumn(name="receiverId", referencedColumnName = "id", updatable=false, insertable=false)
private ProfileLite receiver;
#Column(columnDefinition="TEXT")
private String message;
private long time;
private MessageStatus status;
}
ProfileLite:
#Entity
#Table(name="s_profiles")
public class ProfileLite implements Comparable<ProfileLite>
{
#Id
#GeneratedValue(strategy=GenerationType.AUTO)
private Long id;
private String nickname;
private String country;
private String thumb;
private Gender gender;
}
After executing method mentioned above, hibernate generates about 40 SQL's (based on 40 profiles) like this:
SQL Log - PasteBin
so first collecting messages and then for each message creates another sql to gather profile.
Is it any possibility to push hibernate to create just one simple sql instead of 40 like: select * from s_messages m join s_profiles s1 on m.sender_id = s1.id join s_profiles s2 m_receiver_id = s2.id ? (pseudo code)
Thanks!
This could be a n + 1 problem.
You can use a JOIN FETCH in your JPA query to fix this.
A "fetch" join allows associations or collections of values to be initialized along with their parent objects using a single select. This is particularly useful in the case of a collection. It effectively overrides the outer join and lazy declarations of the mapping file for associations and collections.
Update your JPA repository like so
public interface MessagesRepository extends CrudRepository<Message, Long> {
#Query("Select m from Message m join fetch m.sender ms join fetch m.receiver mr where ms.id = :senderId or mr.id = :receiverId order by m.time desc")
List<Message> findBySenderIdOrReceiverIdOrderByTimeDesc(Long senderId, Long receiverId);
}
For a more detailed explanation check out this answer.
PS: I havent tested the query.
I have an web application with hibernate which manages data in multiple languages. Currently basically every request generates a shower of select statements on the languagetranslations. The models are roughly as following:
Data <1-1> Placeholder <1-many> languageTranslation <many-1> language
If I query for all/many Dataobjects, I see lots of single selects which select one languageTranslation for the placeholder. The SQL I optimally would want to generate:
SELECT * FROM data join placeholder join languagetranslation
WHERE data.placeholder_id = placeholder.id
AND languagetranslation.placeholder_id = placeholder.id
AND languagetranslation.language_id = ?
so that I get every data with placeholder with translation in one single call. The languagetranslations have an composite primary key of language_id and placeholder_id.
I have no HBM file, everything is managed with annotations. Modelcode (only relevant sections are shown):
#Entity
public class Data {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#OneToOne(fetch = FetchType.EAGER, cascade = CascadeType.ALL, optional = false)
#Fetch(FetchMode.JOIN)
private Placeholder content;
}
public class Placeholder {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#OneToMany(mappedBy = "primaryKey.placeholder", cascade = CascadeType.ALL, fetch = FetchType.EAGER, orphanRemoval = true)
#Fetch(FetchMode.JOIN)
private Set<LanguageTranslation> languageTranslations = new HashSet<>();
}
public class LanguageTranslation {
#EmbeddedId
private LanguageTranslationPK primaryKey = new LanguageTranslationPK();
#Type(type = "org.hibernate.type.StringClobType")
private String text;
}
#Embeddable
public class LanguageTranslationPK {
#ManyToOne(fetch = FetchType.EAGER)
#Fetch(FetchMode.JOIN)
private TextPlaceholder textPlaceholder;
#ManyToOne(fetch = FetchType.EAGER)
#Fetch(FetchMode.JOIN)
private Language language;
}
public class Language {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
}
I experimented with FetchType and FetchMode but couldn't generate the behavior I want, it always single selects for single languageTranslations.
I also tried multiple ways to query, criteria based, HQL, and raw SQL. My current raw SQL query is the following:
String sql_query = "select data.*, lt.* from Data as data join languagetranslation as lt on data.content_id = lt.textplaceholder_id";
Query q = getSession().createSQLQuery(sql_query).addEntity("data", Data.class).addJoin("data.content_id", "data.title").addJoin("lt", "data.content.languageTranslations").setResultTransformer(Criteria.DISTINCT_ROOT_ENTITY);
return q.list();
Am I doing something generally wrong here? How can I convince hibernate to get all entities in one single database call? Or is there some other methods to improve performance in my case (e.g. batch selecting)?
You may create proxy pojo which have your all entity variables with getter setter and constructor. then initialize this constructor in hibernate query so that you just get all needed data from database.
import com.proxy;
class userProxy{
private string name;
private string password;
private string address;
private int pincode;
private byte[] profilePic;
private int age;
public userProxy(string name,string password){
this.name = name;
this.password = password;
}
//Getter and setter of all variable...
}
Then use this constructor to Hibernate query like
select new com.proxy.userProxy(user.name,user.password) from usertable
Am I doing something generally wrong here?
No, you are not. That is how Hibernate works.
How can I convince hibernate to get all entities in one single database call
You have to use HQL or SQL query to do that. You do not need to have HBM file. It can be done through #NamedQueries / #NamedQuery annotation with list method.
There are many samples on Internet as example simple one:
http://www.mkyong.com/hibernate/hibernate-named-query-examples/
It's possible mapping custom native/named queries to entities? I have something like this
NamedQueries({
NamedQuery(name = "StateBo.findByCountry", query = "SELECT state FROM StateBo state WHERE state.country.id = ?"),
NamedQuery(name = "StateBo.showIdfindByCountry", query = "SELECT state.id FROM StateBo state WHERE state.country.id = ?")
})
#Table(name = "STATE")
#Entity(name = "StateBo")
public class StateBo extends BaseNamedBo {
private static final long serialVersionUID = 3687061742742506831L;
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "STATE_ID")
private Long id;
#Column(name = "ISO_CODE")
private String isoCode;
#ManyToOne
#JoinColumn(name = "COUNTRY_ID")
private CountryBo country;
// getters and setters ...
}
I have my method to call Native/Named queries like this.
#Override
public List<E> executeQuery(String queryName, List<Object> criteria) {
TypedQuery<E> query = entityManager.createNamedQuery(queryName, entityClass);
Integer argumentPosition = 1;
if ( (criteria != null) && (criteria.size() > 0) ){
for(Object object : criteria) {
query.setParameter(argumentPosition, object);
argumentPosition++;
}
}
return (List<E>) query.getResultList();
}
When I call the StateBo.findByCountry the result is mapped to StateBo, but if I call StateBo.showIdfindByCountry the result is not mapped to StateBo because I'm only selected on the query the state.id instead of the fields on the table.
I don't want to select all the fields of the STATE table, I only want in this case the state.id, but when I customize my native query, the result is not mapped to StateBo instead of this, the result is a Long type.
My question is, Is possible map to an Entity the result of StateBo.showIdfindByCountry? I case that I have more fields like state.isoCode, is possible map to StateBo, the custom query? or only is possible if I return all the fields from the query, like the first query StateBo.findByCountry
It is possible, but as JB Nizet said - "your collegues will suffer from such a design decision".
Anyway, in order to do that you should create custom constructor in your entity class. This constructor should accept Long argument and assign it to id field of your entity class.
Then you should change your query to include NEW keyword followed by full qualified entity class name as below:
SELECT NEW your.package.StateBo(sb.id)
FROM StateBo sb
WHERE state.country.id = ?
Please note that all entities retreived from database in such a way will not be managed by persistence context.