I have a table patient_details(patient_id, first_name, last_name, address,date_of_birth, gender, contact_number,occupation). I have generated an entity class and a PersistenceUnit. I can only find an object using its ID:
PatientDetails pd = em.find(PatientDetails.class,patient_id);
I want to know how to find an object by using other column name(s) instead of just the primary key.
Have a look on JPQL or JPA Critera.
https://docs.oracle.com/html/E24396_01/ejb3_langref.html
http://docs.oracle.com/javaee/6/tutorial/doc/gjitv.html
Execute Querys:
http://docs.oracle.com/javaee/6/api/javax/persistence/EntityManager.html#createQuery%28javax.persistence.criteria.CriteriaQuery%29
For example:
if
class PatientDetails
String first_name;
#Column(",date_of_birth")
Date birth;
...
}
then
String sql = "SELECT p FROM PatientDetails p where p.first_name = :fname and p.birth > :generation";
Date generation = new Date(int 1980, 0, 1);
TypedQuery<PatientDetails> query = EM.createQuery(sql);
query.setParameter("fname","John");
query.setParameter("generation",generation);
return query.getResultList
returns patients called John and born after 1980.
But you should read the links recommended by #pL4Gu33
Related
I have multiple aggregate classes, such as Request, Scribe, Candidate, and Exam.
Sample schema:
Request (id, scribe_id, candidate_id, exam_id, status)
Scribe (id, name)
Candidate (id, name)
Exam (id, name, schedule)
As you can see, Request table has references to Scribe, Candidate, and Exam tables.
For one of the requirements, I need to return all requests based on a condition by including all the corresponding details of scribe, candidate, and exam.
For this, the query in my repository class will be similar to the following:
SELECT r.id, r.status, c.name, s.name,
e.schedule, e.name
FROM request r
JOIN candidate c ON r.candidate=c.id
JOIN scribe s ON r.scribe=s.id
JOIN exam e ON r.exam=e.id
WHERE <some-condition>
Now, is there a way to map the result of this query directly to a custom Java object and return the same in Spring Data JDBC?
I believe another alternative is to use the Spring JDBC template.
Curious, any out-of-the-box support from Spring Data JDBC?
Thanks.
I am able to return custom Java object by setting rowMapperClass value of org.springframework.data.jdbc.repository.query.Query annotation. For this need to define RowMapper for custom Java object.
Changes look similar to the following:
public class RequestResourceRowMapper implements RowMapper<RequestResource> {
#Override
public RequestResource mapRow(ResultSet resultSet, int rowNumber) throws SQLException { ... }
}
In repository class, need to set rowMapper value.
#Query(value = """
SELECT r.id, r.status, c.name, s.name,
e.schedule, e.name
FROM request r
JOIN candidate c ON r.candidate=c.id
JOIN scribe s ON r.scribe=s.id
JOIN exam e ON r.exam=e.id
WHERE <some-condition>
""",
rowMapperClass = RequestResourceRowMapper.class)
List<RequestResource> searchRequestResources(...);
This could have even been possible without using a custom row mapper as well, but in that case, you will have to assign different names to the columns across the tables. You could have defined a simple class and defined all the fields in there and for mapping the java fields with the corresponding columns in the table, you could have used the #Column attributes example:
public class RequestData {
#Column("id")
private Integer requestId;
#Column("scribe_id")
private String scribeId;
#Column("candidate_id")
private Integer candidateId;
#Column("scribe_name")
private String scribeName;
#Column("candidate_name")
private String candidateName;
#Column("exam_name")
private String examName;
#Column("exam_schedule")
private String examSchedule;
}
However, for such case, you need to have different column names across the schema's which might not be possible in your case as you have same column names in multiple schemas.
I created a a query to only get 4 items from a row in a table which does not include the column cloth style, so i understand why i get the error, but how can i tell Spring Jpa or JPA it is on purpose. and i just want the id, name and color table ?
this is my code:
#RequestMapping(value = "/query/material",method = RequestMethod.GET)
public String QueryMaterialTable(HttpServletRequest request){
DataTableRequest<Material> dataTableInRQ = new DataTableRequest<Material>(request);
PaginationCriteria pagination = dataTableInRQ.getPaginationRequest();
String baseQuery = "SELECT id as id, time as time, name as name, color as color, price as price, (SELECT COUNT(1) FROM MATERIAL) AS totalrecords FROM MATERIAL";
String paginatedQuery = AppUtil.buildPaginatedQuery(baseQuery, pagination);
System.out.println(paginatedQuery);
Query query = entityManager.createNativeQuery(paginatedQuery, Material.class);
#SuppressWarnings("unchecked")
List<Material> materialList = query.getResultList();
DataTableResults<Material> dataTableResult = new DataTableResults<Material>();
dataTableResult.setDraw(dataTableInRQ.getDraw());
dataTableResult.setListOfDataObjects(materialList);
if (!AppUtil.isObjectEmpty(materialList)) {
dataTableResult.setRecordsTotal(String.valueOf(materialList.size())
);
if (dataTableInRQ.getPaginationRequest().isFilterByEmpty()) {
dataTableResult.setRecordsFiltered(String.valueOf(materialList.size()));
} else {
dataTableResult.setRecordsFiltered(String.valueOf(materialList.size()));
}
}
return new Gson().toJson(dataTableResult);
}
If I got the question right, your problem is with the following two lines:
Query query = entityManager.createNativeQuery(paginatedQuery, Material.class);
List<Material> materialList = query.getResultList();
You have various options to fix this:
provide a complete column list, i.e. provide the missing column in the SQL statement and just make them NULL;
Don't use Material but a new class that has the matching attributes.
Don't use a native query but JPQL and a constructor expression.
Use a ResultTransformer.
Use Spring Data and a Projection.
Use a Spring JdbcTemplate.
I'm new in Grails. I have a problem with generation association many to one and one to many between two tables. I'm using postgresql database.
Employee.groovy
class Employee {
String firstName
String lastName
int hoursLimit
Contact contact
Account account
Unit unit
char isBoss
static hasMany = [positionTypes:PositionType, employeePlans: EmployeePlan]
}
EmployeePlan.groovy
class EmployeePlan {
AcademicYear academicYear
HourType hourType
int hours
float weightOfSubject
Employee employee
static belongsTo = [SubjectPlan]
}
I'd like to have access from employee to list of employeePlans and access from EmployeePlan to Employee instance. Unfortunately GORM generates only two tables Employee and EmployeePlan with employee_id. I don't have third table which should have two columns employee_id and employee_plan_id. Could you help me ?
I think your setup is correct, as you write from Employee class you can access to a collection of EmployeePlan (take care, that if you don't explicitly define EmployeePlan like a List, it will be a Set by default) and from EmployeePlan you can access Employee.
If you need List, you can define it like that:
class Employee {
String firstName
String lastName
int hoursLimit
Contact contact
Account account
Unit unit
char isBoss
//explicitly define List
List<EmployeePlan> employeePlans
static hasMany = [positionTypes:PositionType, employeePlans: EmployeePlan]
}
But back to your question. You'd like to have join table between Employee and employeePlan, but why? Its not necessary, since you have bidirectional mapping with sets (unordered), grails will not create a join table. Can you explain why do you need it? In grails the references will be auto-populated, so I don't see any issue here.
If need to preserve order of employeePlans, then define it as List, shown above, and grails will create a join table with corresponding indexes.
have you read the ref-doc? it gives you the answer immediately:
class Person {
String firstName
static hasMany = [addresses: Address]
static mapping = {
table 'people'
firstName column: 'First_Name'
addresses joinTable: [name: 'Person_Addresses',
key: 'Person_Id',
column: 'Address_Id']
}
}
I have the following JPA Entity I want to update:
#Entity(name = "EmployeeImpl")
#Table(name = "EmployeeImpl")
public class EmployeeImpl {
#Id
#Column(name = "employeeId")
#GeneratedValue(strategy = GenerationType.AUTO)
private long id;
#ElementCollection
private List<String> phonenumber;
}
I thought I use a namedQuery like so
#NamedQuery(name = "updateEmployee",
query = "Update EmployeeImpl e SET e.phonenumber :number WHERE e.id = :id")
But that doesn't work: Exception Description: Error compiling the query [updateEmployee: Update EmployeeImpl e SET e.phonenumber = :number WHERE e.id = :id], line 1, column 28: invalid access of attribute [phonenumber] in SET clause target [e], only state fields and single valued association fields may be updated in a SET clause.
Question is, how do I update an #ElementCollection? If it's possible i'd like to do it with a jpql query.
No, that is not possible in JPQL. As kostja says: the message says it clear and also according to the JPA specification, Chapter "4.10 Bulk Update and Delete Operations" you may update only state fields and single values object fields.
The syntax of these operations is as follows:
update_statement ::= update_clause [where_clause]
update_clause ::= UPDATE entity_name [[AS] identification_variable]
SET update_item {, update_item}*
update_item ::= [identification_variable.]{state_field | single_valued_object_field} = new_value
new_value ::=
scalar_expression |
simple_entity_expression |
NULL
WHAT TO DO?
Probably the most clean way to do that is simply to fetch the entities and to add/replace the phone number/s, although you can always do that also with Native Queries, i.e SQL queries as kostja says.
The reason for the failure is stated in the error message. You cannot use bulk updates on non-singular attributes of your entity, since they are stored in a different table.
How do you do it instead? You update the collection table.
The default table name for collection tables is <parent_entity>_<field_name>. So the table you are interested in should be named EmployeeImpl_phonenumber. The id column for the EmployeeImpl (the foreign key) should be named EmployeeImpl_id per default.
EDIT What I posted initially was not valid in JPQL. You might want to use a native query instead. It is simple, so it should be portable:
The native query could then look like this:
UPDATE EmplyeeImpl_phonenumber
SET phonenumber = ?
WHERE employeeimpl_id = ?
I have the following QueryDSL query:
QCustomer customer = QCustomer.customer;
BooleanBuilder builder = new BooleanBuilder();
builder.or(customer.person.name.containsIgnoreCase(query));
builder.or(customer.company.name.containsIgnoreCase(query));
return builder;
And I expect to get results from Persons that contains the name = query and/or Companies that contains the query parameter. But I get nothing.
This is my Customer class mapping:
#OneToOne(orphanRemoval = false, optional = true, cascade = CascadeType.ALL)
private Company company;
#OneToOne(orphanRemoval = false, optional = true, cascade = CascadeType.ALL)
private Person person;
Did someone knows what I'm missing here?
I expect to get a query like this:
select o
from Customer
where o.person.name like '%:name%' or o.company.name like '%:name%'
This is the generated query:
select
count(customer0_.uid) as col_0_0_
from
Customer customer0_
cross join
Person person1_
cross join
Company company2_
where
customer0_.person_uid=person1_.uid
and customer0_.company_uid = company2_.uid
and (lower(person1_.name) like ? escape '!' or lower(company2_.name) like ? escape '!') limit ?
It uses a count because it's the first query that Spring Data use to paginate the result.
The query looks ok. Most probably you get wrong results because the implicit property based joins make the joins inner joins.
Using left joins you might get the results you need.
QPerson person = QPerson.person;
QCompany company = QCompany.company;
BooleanBuilder builder = new BooleanBuilder();
builder.or(person.name.containsIgnoreCase(str));
builder.or(company.name.containsIgnoreCase(str));
query.from(customer)
.leftJoin(customer.person, person)
.leftJoin(customer.company, company)
.where(builder);