Here is my entity class:
public class User {
#Id
UserIdentifier userIdentifier;
String name;
}
public class UserIdentifier {
String ssn;
String id;
}
Here is what I am trying to do:
public interface UserRepository extends MongoRepository<User, UserIdentifier>
{
User findBySsn(String ssn);
}
I get an exception message (runtime) saying:
No property ssn found on User!
How can I implement/declare such a query?
According to Spring Data Repositories reference:
Property expressions can refer only to a direct property of the managed entity, as shown in the preceding example. At query creation time you already make sure that the parsed property is a property of the managed domain class. However, you can also define constraints by traversing nested properties.
So, instead of
User findBySsn(String ssn);
the following worked (in my example):
User findByUserIdentifierSsn(String ssn);
Related
I am working with Spring Data 2.0.6.RELEASE.
I am working about pagination for performance and presentation purposes.
Here about performance I am talking about that if we have a lot of records is better show them through pages
I have the following and works fine:
interface PersonaDataJpaCrudRepository extends PagingAndSortingRepository<Persona, String> {
}
The #Controller works fine with:
#GetMapping(produces=MediaType.TEXT_HTML_VALUE)
public String findAll(Pageable pageable, Model model){
Through Thymeleaf I am able to apply pagination. Therefore until here the goal has been accomplished.
Note: The Persona class is annotated with JPA (#Entity, Id, etc)
Now I am concerned about the following: even when pagination works in Spring Data about the amount the records, what about of the content of each record?.
I mean: let's assume that Persona class contains 20 fields (consider any entity you want for your app), thus for a view based in html where a report only uses 4 fields (id, firstname, lastname, date), thus we have 16 unnecessary fields for each entity in memory
I have tried the following:
interface PersonaDataJpaCrudRepository extends PagingAndSortingRepository<Persona, String> {
#Query("SELECT p.id, id.nombre, id.apellido, id.fecha FROM Persona p")
#Override
Page<Persona> findAll(Pageable pageable);
}
If I do a simple print in the #Controller it fails about the following:
java.lang.ClassCastException:
[Ljava.lang.Object; cannot be cast to com.manuel.jordan.domain.Persona
If I avoid that the view fails with:
Caused by:
org.springframework.expression.spel.SpelEvaluationException:
EL1008E:
Property or field 'id' cannot be found on object of type
'java.lang.Object[]' - maybe not public or not valid?
I have read many posts in SO such as:
java.lang.ClassCastException: [Ljava.lang.Object; cannot be cast to
I understand the answer and I am agree about the Object[] return type because I am working with specific set of fields.
Is mandatory work with the complete set of fields for each entity? Should I simply accept the cost of memory about the 16 fields in this case that never are used? It for each record retrieved?
Is there a solution to work around with a specific set of fields or Object[] with the current API of Spring Data?
Have a look at Spring data Projections. For example, interface-based projections may be used to expose certain attributes through specific getter methods.
Interface:
interface PersonaSubset {
long getId();
String getNombre();
String getApellido();
String getFecha();
}
Repository method:
Page<PersonaSubset> findAll(Pageable pageable);
If you only want to read a specific set of columns you don't need to fetch the whole entity. Create a class containing requested columns - for example:
public class PersonBasicData {
private String firstName;
private String lastName;
public PersonBasicData(String firstName, String lastName) {
this.firstName = fistName;
this.lastName = lastName;
}
// getters and setters if needed
}
Then you can specify query using #Query annotation on repository method using constructor expression like this:
#Query("SELECT NEW some.package.PersonBasicData(p.firstName, p.lastName) FROM Person AS p")
You could also use Criteria API to get it done programatically:
CriteriaBuilder cb = entityManager.getCriteriaBuilder();
CriteriaQuery<PersonBasicData> query = cb.createQuery(PersonBasicData.class);
Root<Person> person = query.from(Person.class);
query.multiselect(person.get("firstName"), person.get("lastName"));
List<PersonBasicData> results = entityManager.createQuery(query).getResultList();
Be aware that instance of PersonBasicData being created just for read purposes - you won't be able to make changes to it and persist those back in your database as the class is not marked as entity and thus your JPA provider will not work with it.
Say I have a #MappedSuperClass like this:
#MappedSuperclass
public abstract class Rating
{
#Id
private Long id;
#Column(name="USER_ID")
private Long userId;
private int rating;
...
With a concrete child entity like this
#Entity
#Table(name="ACTIVITY_RATING")
public class ActivityRating extends Rating
{
private Long activitySpecificData;
...
Then there is a Spring Data JPA repository like this:
#NoRepositoryBean
public interface RatingRepository<R extends Rating> extends JpaRepository<R, ID>
{
public List<R> findByUserId(Long userId);
...
and this:
public interface ActivityRatingRepository extends RatingRepository<ActivityRating>
{
}
This all works great and I can call findByUserId() on any of specific rating repositories that extend RatingRepository. I am now wanting to write some JPQL in the RatingRepository that all the child interfaces can inherit. I just don't know what (or if it's even possible) to put after the FROM in the query. For example:
#Query("SELECT NEW com.foo.RatingCountVo(e.rating, COUNT(e.rating)) FROM ??????? e GROUP BY e.rating")
public List<RatingCountVo> getRatingCounts();
I can add this method to each of the individual repositories that extend RatingRepository but everything would be exactly the same except for the specific entity name. If I want to change the query, I'd then have to go to all the child repositories and update them individually. I really want the query to live in the parent class and not be duplicated. Is there any way to accomplish this?
I'm currently using spring-data-jpa 1.7.2 and eclipselink 2.5.2. I'm not necessarily opposed to switching to newer versions if necessary.
Will it work if you will split query into 3 parts: start, entity and end of query? Than, if it'll work, in each interface you define constant like
String ENTITY = "ActivityRating";
And then you can use it like
#Query(RatingRepository.QUERY_START + ENTITY + RatingRepository.QUERY_END)
List<RatingCountVo> getRatingCounts();
BTW, there is no need to define public modifier in interface.
UPDATE: here is described another way:
#Query("SELECT NEW com.foo.RatingCountVo(e.rating, COUNT(e.rating)) FROM #{#entityName} e GROUP BY e.rating
I use code first approach in my project. In the prject I have classes with MetadataType attribute, which I don't use in my EF model. Class with metadata has some constant public fields (in addition to fields from main type). Now when I tried to query EF it threw exception that in metadata class there fields not mapped... se below in details
class M1
{
int Id;
string Name
}
class M2
{
int Id;
DateTime Date
}
[MetadataType(typeof(PageOFSRevenueMetadata))]
class NotRelatedToModel
{
int Prop1;
int Prop2;
}
class PageOFSRevenueMetadata
{
public const string RuleSet1 = "r1";
public const string RuleSet2 = "r2";
// Data Vaidation Attrs...
int Prop1;
int Prop2;
}
In my context I have mapping only for M1 and M2. In the DB exists table with name 'NotRelatedToModel', but I don't want to use it in my model. I use EF 6
Now when I try to make join query on M1 and M2 it threw below exception
'NotRelatedToModel' contains the following unknown properties or fields: RuleSet1, RuleSet2. Please make sure that the names of these members match the names of the properties on the main type
I can move this static fields to another place and it seems to work, but I would like to know why it is happend ? How the EF code first mapping works ?
Thanks in advance
I try to use inheritance with Ebean in Play! Framework 2.1.0. The inheritance strategy is "single table", as it is the only one supported by Ebean. I closely follow example from JPA Wikibook
#Entity
#Inheritance
#DiscriminatorColumn(name="price_type")
#Table(name="prices")
public abstract class Price {
#Id
public long id;
// Price value
#Column(precision=2, scale=18)
public BigDecimal value;
}
#Entity
#DiscriminatorValue("F")
public class FixedPrice extends Price {
// NO id field here
...
}
#Entity
#DiscriminatorValue("V")
public class VariablePrice extends Price {
// NO id field here
...
}
This code passes compilation, but I get
RuntimeException: Abstract class with no readMethod for models.Price.id
com.avaje.ebeaninternal.server.deploy.ReflectGetter.create(ReflectGetter.java:33)
com.avaje.ebeaninternal.server.deploy.BeanDescriptorManager.setBeanReflect(BeanDescriptorManager.java:1353)
com.avaje.ebeaninternal.server.deploy.BeanDescriptorManager.createByteCode(BeanDescriptorManager.java:1142)
com.avaje.ebeaninternal.server.deploy.BeanDescriptorManager.readDeployAssociations(BeanDescriptorManager.java:1058)
com.avaje.ebeaninternal.server.deploy.BeanDescriptorManager.readEntityDeploymentAssociations(BeanDescriptorManager.java:565)
com.avaje.ebeaninternal.server.deploy.BeanDescriptorManager.deploy(BeanDescriptorManager.java:252)
com.avaje.ebeaninternal.server.core.InternalConfiguration.<init>(InternalConfiguration.java:124)
com.avaje.ebeaninternal.server.core.DefaultServerFactory.createServer(DefaultServerFactory.java:210)
com.avaje.ebeaninternal.server.core.DefaultServerFactory.createServer(DefaultServerFactory.java:64)
com.avaje.ebean.EbeanServerFactory.create(EbeanServerFactory.java:59)
play.db.ebean.EbeanPlugin.onStart(EbeanPlugin.java:79)
Google search brings only one relevant link which is source code of ReflectGetter.java. The comment there says
For abstract classes that hold the id property we need to use reflection to get the id values some times.
This provides the BeanReflectGetter objects to do that.
If I drop abstract keyword from superclass declaration, exception disappears. I would really prefer not to make superclass concrete though.
Add getter/setter for your id field and it will go away.
As far as I am aware, for the property to be saved in the database it cannot be ReadOnly.
IIdentity properties: AuthenticationType, IsAuthenticated and Name are all ReadOnly.
Is making the wrapper to the properties that need to be saved the only solution or there are better ones?
EDIT:
I might not have explained my question that well. Here is the sample code for one of the ReadOnly properties, I have added UserName property for the Entity Framework:
Public Property UserName As String
Get
Return _userName
End Get
Private Set(value As String)
userName = value
End Set
Public ReadOnly Property Name As String Implements System.Security.Principal.IIdentity.Name
Get
Return UserName
End Get
End Property
What I wanted to ask is if there is any better way of doing it.
IIdentity properties are read only but the implementation can have setters. If you are using EDMX for mapping you don't have to expose these setters as public.
Edit:
This is possible in C# so hopefully you can use similar approach with VB.NET (I can only read VB code, not write):
public interface ITest {
string Name { get; }
}
public class Test : ITest {
public string Name { get; set; }
}
The class offers setter even the interface didn't define it.
The EF persists objects, not interfaces. Your object can have whatever properties you would like it to have. You cannot add an interface to your entity model, but you can add an object type which implements that interface.