I have two entities connected bidirectional and I want to query the Location and its votes only for a specific date.
Location:
#Entity
#Table(name = "TAB_LOCATION")
#NamedQueries({
#NamedQuery(name = "Location.getVotedLocations", query = "SELECT l FROM Location l JOIN l.votes v WHERE v.location = l AND DATE(v.createdAt) = DATE(:date) ORDER BY l.name")
})
public class Location extends AbstractEntity {
#Basic
#Size(min = 5, max = 50)
private String name;
#Basic
#Size(min = 0, max = 50)
private String address;
#OneToMany(mappedBy = "location")
private Set<Vote> votes;
#Basic
private String description;
Vote:
#Entity
#Table(name = "TAB_VOTE")
public class Vote extends AbstractEntity {
#Basic
#ManyToOne
#NotNull
private User user;
#Basic
#ManyToOne
#NotNull
private Location location;
I was trying to use the named query but it seems that the Location always contains all votes regardless the condition.
Isn't it possible to map the queried values back to the object?
entityManager.createNamedQuery("Location.getVotedLocations").
setParameter("date", date).getResultList();
What is wrong?
If it isn't possible with NamedQueries, I also can use the Criteria API.
Here's a simple MySql statement that will return locationIDs not Location entity which are voted on a particular date.
Select DISTINCT LocationID FROM VOTE WHERE DATE == dateCreated;
And you can then get the Location entity by LocationID.
When you get an entity as a result from some query, you get the whole entity. It is not possible in JPA to get just a subset of all data, trimmed by where condition.
Well, if you use Hibernate, take a look at Hibernate Filters, with them you could get the result you want.
Note about your query, you have JOIN l.votes so you don't need to join it again with WHERE v.location = l.
Related
Let say I have an entity object Customer with an "OneToMany" relation to Order. I want that when ever a "Customer" get loaded, only his orders with the Id = 1234, 5678 get loaded to.
Any ideas?
#Entity
#Table(name = "Customer")
public class Customer extends TraceableJPA {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "customer_id")
private Long id;
#OneToMany(cascade = CascadeType.ALL, mappedBy = "Customer", targetEntity = Order.class)
#Column(name = "order_id", value = {"1234","5678"} (?))
#OrderBy("isrtdate ASC")
#BatchSize(size = 20)
private List<Order> orders = new ArrayList<Order>();
Hibernate
If you use hibernate Session and its abilites , you can always use #FilterJoinTable mechanism.
Check THIS article for more information.
Yet it is not global, you have to predefine this filter and then explicitly configure Session object to use it.
JPA
JPA in its standard has NO SUCH FUNCTIONALITY, for global relations filtering.
You can always filter it in your queries : )
I am attempting to have a station projection include a list of associated logos. Below is my domain:
#Table(name = "Station")
public class Station implements Serializable {
#Id
#Column(name = "Id")
private int id;
#OneToMany(cascade = CascadeType.ALL,
fetch = FetchType.LAZY,
mappedBy = "station")
private Set<Logo> logos;
}
The #OneToMany associated logos:
#Table(name = "Logo")
public class Logo {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private int id;
#Transient
private String fullUrl; // calculated
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "StationId", nullable = false)
private Station station;
}
My repository and query is as follows:
#Query(value = "SELECT s.id AS Id, s.logos As Logos FROM Station s JOIN s.users su WHERE su.username = ?1")
Collection<StationListViewProjection> findStationsByUsername(String username);
My station projection expects the Id and a list of logoProjections
#Projection(name = "StationListViewProjection", types = Station.class)
public interface StationListViewProjection {
int getId();
Set<LogoProjection> getLogos();
}
The logoProjection only needs the url
#Projection(name = "LogoProjection", types = Logo.class)
public interface LogoProjection {
String getFullUrl();
}
When i execute my query I get a strange response:
MySQLSyntaxErrorException: 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_5_0_, . as col_6_0_, stationlog3_.id as id1_20_0_'
If I understand this
#Transient
private String fullUrl; // calculated
correct, your fullUrl gets calculated inside your java code and more important, it doesn't have a matching column in the database. You can't use such field in projections directly. You might be able to use an Open Projection and specify the calculation to obtain the fullUrl using a #Value annotation.
I need assistance in troubleshooting a relationship / query with EclipseLink 2.5.x provider.
The relationship from ThreePhaseMotorInput to ValidationMessage is supposed to be a uni-directional OneToMany, i.e. each motor can have 0..n messages and in Java object graph ValidationMessage does not have a reference back to ThreePhaseMotorInput.
I am getting an error that JPA can't find the attributes that are part of the ValidationMessage class when accessed via ThreePhaseMotor. (See error text below)
Thanks for thinking about my question!
Query
select msg.validationMsg, COUNT(m.id) from ThreePhaseMotorInput AS m JOIN m.valMessages AS msg GROUP BY msg.validationMsg
Error
org.eclipse.persistence.exceptions.JPQLException:
Exception Description: Problem compiling [select msg.validationMsg, COUNT(m.id) from ThreePhaseMotorInput AS m JOIN m.valMessages AS msg GROUP BY msg.validationMsg].
[7, 24] The state field path 'msg.validationMsg' cannot be resolved to a valid type.
[71, 84] The collection-valued path 'm.valMessages' cannot be resolved to a valid association field.
[119, 136] The state field path 'msg.validationMsg' cannot be resolved to a valid type.
ThreePhaseMotorInput class
#Entity
#Table(name = "three_phase_motor_input")
public class ThreePhaseMotorInput implements IThreePhaseMotorInput, Serializable {
private static final long serialVersionUID = 8084370807289186987L;
#Transient
private final PropertyChangeSupport propertyChangeSupport = new PropertyChangeSupport(this);
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#Version
private Integer version;
private Integer status;
#Transient
private Integer numMessages;
#OneToOne(cascade = CascadeType.ALL, optional = true, targetEntity = UnapprovedThreePhaseMotor.class)
#JoinColumn(name = "unapproved_id")
private IThreePhaseMotor unapprovedMotor;
#OneToOne(cascade = CascadeType.ALL, optional = true, targetEntity = ApprovedThreePhaseMotor.class)
#JoinColumn(name = "approved_id")
private IThreePhaseMotor approvedMotor;
#OneToMany(orphanRemoval = true, cascade = CascadeType .ALL, fetch = FetchType.LAZY, targetEntity = ValidationMessage.class)
#JoinColumn(name = "input_id", referencedColumnName = "id", nullable = false)
#OrderColumn(name = "idx")
private List<IValidationMessage> valMessages;
ValidationMessage class
#Entity
#Table(name = "validation_message")
public class ValidationMessage implements Serializable, IValidationMessage {
private static final long serialVersionUID = 8765213112015434057L;
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#Column(name = "record_id")
private Long recordId;
#Column(name = "field_name")
private String fieldName;
#Column(name = "validation_msg")
private String validationMsg;
private Integer status;
#Column(name = "fail_field")
private String failField;
#Column(name = "error_source")
private Integer errorSource;
The problem seems to be in the following query: select m.approvedMotor, m.valMessages, m.valMessages.validationMsg, count(m.valMessages.id) from ThreePhaseMotorInput m group by m.valMessages.validationMsg.
That query should be a JPQL query, i.e a query where you specify entities and their Java properties. Also you must use JOINs if you want to jump to another entity's properties: m.valMessages.validationMsg is not correct, but INNER JOIN m.valMessages msg GROUP BY msg is correct.
So try the following query:
select m, COUNT(msg) from ThreePhaseMotorInput AS m LEFT JOIN m.valMessages AS msg GROUP BY msg.validationMsg
You can't use a path expression with a Collection value association.
The documentation says: JPQL Path Expressions
It is syntactically illegal to compose a path expression from a path expression that evaluates to a collection.
In your query, m.valMessages is illegal because it references a collection of ValidationMessages.
In the other hand, m.approvedMotor is legal because it is a single value association.
As suggested in Andrei response, you need to modify your query to add another path expression:
select msg.validationMsg, COUNT(m.id) from ThreePhaseMotorInput m JOIN m.valMessages msg GROUP BY msg.validationMsg
you should use JOINs if you want to jump to another entity's properties. try the following JPQL query
select m, COUNT(msg) from ThreePhaseMotorInput AS m LEFT JOIN m.valMessages AS msg GROUP BY msg.validationMsg
I want make a query where I join 2 tables, using the CriteriaBuilder. In MySQL the query I'm trying to make would look like this:
SELECT * FROM order
LEFT JOIN item
ON order.id = item.order_id
AND item.type_id = 1
I want to get all orders and if they have an item of type #1, I want to join with this item. However, if no item of type #1 is found, I still want to get the order. I can't figure out how to make this with the CriteriaBuilder. All I know how to make is:
CriteriaBuilder cb = em.getCriteriaBuilder();
CriteriaQuery<Order> cq = cb.createQuery(Order.class);
Root<Order> order = cq.from(Order.class);
Join<Order, Item> item = order.join(Order_.itemList, JoinType.LEFT);
Join<Item, Type> type = order.join(Item_.type, JoinType.LEFT);
cq.select(order);
cq.where(cb.equal(type.get(Type_.id), 1));
This query is broke, since it results in something like this in MySQL:
SELECT * FROM order
LEFT JOIN item
ON order.id = item.order_id
WHERE item.type_id = 1
The result will only contain orders with items of type #1. Orders without are excluded. How can I use the CriteriaBuilder to create a query like in the first example?
It is possible starting from the version 2.1 of JPA using the on method Join<Z, X> on(Predicate... restrictions);
Here is how:
Root<Order> order = cq.from(Order.class);
Join<Order, Item> item = order.join(Order_.itemList, JoinType.LEFT);
item.on(cb.equal(item.get(Item_.type), 1));
I think this is the same problem as posed in this question. It looks like it is not possible in CriteriaBuilder. It is possible in Hibernate Criteria API, but that probably won't help you.
JPA Criteria API: Multiple condition on LEFT JOIN
I know this question was made a long time a go, but recently a had the same problem and i found this solution from an Oracle forum, i copied and pasted just in case the link is not longer available.
MiguelChillitupaArmijos 29-abr-2011 1:41 (en respuesta a 840578) Think
you should use something like:
em.createQuery("SELECT DISTINCT e.Id" +
" from Email e " +
" left join e.idEmailIn e2 *with* e2.responseType = 'response'" +
" where e.type = 'in' and e.responseMandatory = true").getSingleResult();
An this is the link.
JPA Criteria : LEFT JOIN with an AND condition
There is a workaround if you are using Hibernate 3.6 with JPA 2.0
It is not the better solution, however it works perfect for me.
I´ve duplicate the entity with the #Where hibernate annotation.It means that everytime you use the join with this entity, hibernate will add the extra condition on the join statement at generated SQL.
For instance, initially we have the follow example:
#Entity
#Table(name = "PERSON")
public class Person {
#Id
#Column(name = "PERSON_ID")
private Long id;
#Id
#Column(name = "PERSON_NAME")
private String name;
#OneToMany(mappedBy = "person", fetch = FetchType.LAZY)
private Set<Address> addresses;
}
#Entity
#Table(name = "ADDRESS")
public class Address {
#Id
#Column(name = "ADDRESS_ID")
private Long id;
#Id
#Column(name = "ADDRESS_STREET")
private String street;
#ManyToOne
#JoinColumn(name = "PERSON_ID")
private Person person;
}
In order to add extra conditions on criteria Join, we need duplicate the Address #Entity mapping , adding the #Where annotation #Where(clause = " ADDRESS_TYPE_ID = 2").
#Entity
#Table(name = "ADDRESS")
#Where(clause = " ADDRESS_TYPE_ID = 2")
public class ShippingAddress {
#Id
#Column(name = "ADDRESS_ID")
private Long id;
#Id
#Column(name = "ADDRESS_STREET")
private String street;
#OneToOne
#JoinColumn(name = "PERSON_ID")
private Person person;
}
Also, we need to add the duplicate mapping association for the new entity.
#Entity
#Table(name = "PERSON")
public class Person {
#Id
#Column(name = "PERSON_ID")
private Long id;
#Id
#Column(name = "PERSON_NAME")
private String name;
#OneToMany(mappedBy = "person", fetch = FetchType.LAZY)
private Set<Address> addresses;
#OneToOne(mappedBy = "person")
private ShippingAddress shippingAddress;
}
Finally, you can use a join with this specific Entity in your criteria :
PersonRoot.join(Person_.shippingAddress, JoinType.LEFT);
The Hibernate Snippet SQL should seems like this :
left outer join
address shippingadd13_
on person11_.person_id=shippingadd13_.person_id
and (
shippingadd13_.ADDRESS_TYPE_ID = 2
)
ON clause is supported in Hibernate 4.3 version, anyone is aware if there is a parameter indexing issue between the parameter index of the additional custom conditions with the index of the existing mapping filters when doing an outer join with ON clause?
Using the Person entity class below as an example, say I am adding this filter to limit the address types and the filter is enabled to populate the IN clause. The parameter index for the IN clause will cause the issue [2] when I add additional conditions (such as using 'street' column) part of the ON clause. Is is a known issue?
[1] #Filter(name = "addressTypes", condition = "ADDRESS_TYPE in (:supportedTypes)")
[2]
Caused by: ERROR 22018: Invalid character string format for type BIGINT.
private Set addresses;
I have the following entities and would like to seek help on how to query for selected attributes from both side of the relationship. Here is my model. Assume all tables are properly created in the db. JPA provider I am using is Hibernate.
#Entity
public class Book{
#Id
private long id;
#Column(nullable = false)
private String ISBNCode;
#ManyToOne(cascade = CascadeType.DETACH, fetch = FetchType.LAZY, optional = false)
private Person<Author> author;
#ManyToOne(cascade = CascadeType.DETACH, fetch = FetchType.LAZY, optional = true)
private Person<Borrower> borrower;
}
#Inheritance
#DiscriminatorColumn(name = "personType")
public abstract class Person<T>{
#Id
private long id;
#OneToOne(cascade = CascadeType.ALL, fetch = FetchType.EAGER)
private Info information;
}
#Entity
#DiscriminatorValue(PersonType.Author)
public class Author extends Person<Author> {
private long copiesSold;
}
#Entity
#DiscriminatorValue(PersonType.Borrower)
public class Borrower extends Person<Borrower> {
.....
}
#Entity
public class Info {
#Id
private long id;
#Column(nullable=false)
private String firstName;
#Column(nullable=false)
private String lastName;
......;
}
As you can see, the book table has a many to one relation to Person that is not nullable and Person that is nullable.
I have a requirement to show, the following in a tabular format -
ISBNCode - First Name - Last Name - Person Type
How can I write a JPA query that will allow me to select only attributes that I would want. I would want to get the attributes ISBN Code from Book, and then first and last names from the Info object that is related to Person Object that in turn is related to the Book object. I would not want to get all information from Info object, interested only selected information e.g first and last name in this case.
Please note that the relation between the Borrower and Book is marked with optional=true, meaning there may be a book that may not have been yet borrowed by someone (obviously it has an author).
Example to search for books by the author "Marc":
Criteria JPA Standard
CriteriaQuery<Book> criteria = builder.createQuery( Book.class );
Root<Book> personRoot = criteria.from( Book.class );
Predicate predicate = builder.conjunction();
List<Expression<Boolean>> expressions = predicate.getExpressions();
Path<Object> firtsName = personRoot.get("author").get("information").get("firstName");
expressions.add(builder.equal(firtsName, "Marc"));
criteria.where( predicate );
criteria.select(personRoot);
List<Book> books = em.createQuery( criteria ).getResultList();
Criteria JPA Hibernate
List<Book> books = (List<Book>)sess.createCriteria(Book.class).add( Restrictions.eq("author.information.firstName", "Marc") ).list();
We recommend using hibernate criterias for convenience and possibilities.
Regards,