I've already searched a lot but can't get it to work.
I've also found this, which comes close but it requires a unnecessary join and can't ignore case sensitivity: Criteria API not in #ElementCollection
This is the simplified entity:
#Entity(name = "Users")
public class User {
#Id
#Column(columnDefinition = "TEXT")
private String id;
#ElementCollection
#LazyCollection(LazyCollectionOption.FALSE)
private List<String> communities;
}
The jpa/hibernate magic translates this into two tables: users(text id) and users_communities(text id, text communities)
The plain sql statement I would like to map to a criteria is:
select u.id from users u
where u.users_id not in (
select uc.users_id
from users_communities uc
where lower(communities) = 'test_user_app'
);
This is my current java code. How can use "criteriaBuilder.lower()" on the subJoin? Is there no easier way? Isn't it possible to avoid the manual subJoin?
Subquery<String> subquery = criteria.subquery(String.class);
Root<User> subRoot = subquery.from(User.class);
Join<Object, Object> subJoin = subRoot.join("communities");
subquery.select(subRoot.get("id"));
subquery.where(criteriaBuilder.equal(root.get("id"), subRoot.get("id")), subJoin.in("community_to_find"));
return criteriaBuilder.exists(subquery);
Unbelievable that took me all day ...
In case one does NOT need case insensitivity or like expression, the simplest way is:
criteriaBuilder.isMember(
"community_to_find",
criteria.from(User.class).get("communities")
);
In case one DOES require like expressions or case insensitivity:
It doesn't seem it's currently possible to avoid the unnecessary sub join! Anyway this is finally making my tests green again :-) :
Subquery<String> subquery = criteria.subquery(String.class);
Root<User> subRoot = subquery.from(User.class);
subquery.select(subRoot.get("id"));
subquery.where(criteriaBuilder.like(criteriaBuilder.lower(subRoot.join("communities")), argument));
return criteriaBuilder.in(root.get("id")).value(subquery);
Hint:
You do probably already have the Root defined from the outer query and since it's an ElementCollection it's most likely the same class.
In that case you can define the subRoot more generic by just:
Root<? extends User> subRoot = subquery.from(root.getJavaType());
Related
I get following error when doing a rather complicated query: for SELECT DISTINCT, ORDER BY expressions must appear in select list
In the query I need to find all distinct Requests that have an ExploitationSite that contains a search term in their dutch or french name. The result has to be ordered by the Activity's dutch name and limited to the first 10 for pagination.
To do this query I use the Page <T> findAll(Specification<T> spec, Pageable pageable) method of JpaSpecificationExecutor.
This will result in a SELECT DISTINCT query which has to be ORDERed BY a property that is not in SELECT. (details below)
I tried to fetch the activities eagerly in the hope it would place those differently in the SELECT. I did my best trying to get the DISTINCT in a subquery and then have the ORDER BY + LIMIT around that, but I did not succeed in that.
Has someone an idea how I can get this query to work?
The (simplified) Request entity
#Entity
#Table(name = "request_requests")
#History("Request")
public class Request extends EqualByStateObject {
#GeneratedValue
#Id
private int id;
#Embedded
private RequestNumber requestNumber;
#OneToMany(cascade = CascadeType.ALL, orphanRemoval = true)
#JoinColumn(name = "fk_request")
private List<ExploitationSite> exploitationSites = new ArrayList<>();
#OneToOne(cascade = CascadeType.ALL)
#JoinColumn(unique = true, name = "fk_activity")
private Activity activity;
...
}
The Specification (I have to use distinct here because since a Request contains a List of ExploitationSites it was possible I got the same request multiple times back if multiple ExploitationSites contained the search term)
public class ExploitationSiteSpecification extends EqualByStateObject implements Specification<Request> {
private final String exploitationSiteName;
protected ExploitationSiteSpecification(String exploitationSiteName) {
this.exploitationSiteName = exploitationSiteName;
}
#Override
public Predicate toPredicate(Root<Request> root, CriteriaQuery<?> query, CriteriaBuilder criteriaBuilder) {
query.distinct(true);
ListJoin<Object, Object> exploitationSites = root.joinList("exploitationSites");
return criteriaBuilder.or(
criteriaBuilder.like(
criteriaBuilder.lower(exploitationSites.get("name").get("dutchName")), "%" + exploitationSiteName.toLowerCase() + "%"),
criteriaBuilder.like(
criteriaBuilder.lower(exploitationSites.get("name").get("frenchName")), "%" + exploitationSiteName.toLowerCase() + "%")
);
}
}
The Pageable
public Pageable getPageable() {
Sort sort = Sort.by(Sort.Order.asc("activity.name.dutchName"));
PageRequest.of(0, 10, sort);
}
This results in a generated query like this one
select distinct request0_.id as id1_23_,
request0_.fk_activity as fk_acti15_23_,
request0_.request_number as request12_23_
from request_requests request0_
inner join request_exploitation_sites exploitati1_ on request0_.id=exploitati1_.fk_request
left outer join request_activity activity2_ on request0_.fk_activity=activity2_.id
where lower(exploitati1_.dutch_name) like $1
or lower(exploitati1_.french_name) like $2
order by activity2_.dutch_name asc limit $3
which then gives the for SELECT DISTINCT, ORDER BY expressions must appear in select list error
Assuming you put the distinct because the join with exploitationSites would return multiple rows, the following two options would work without using distinct.
right after the join you could do an additional fetch
ListJoin<Object, Object> exploitationSites = root.joinList("exploitationSites");
root.fetch("exploitationSites")
this would result in hibernate to create an additional join of ExploitationSites as well as selecting additional columns
select request0_.id as id1_23_,
request0_.fk_activity as fk_acti15_23_,
request0_.request_number as request12_23_,
exploitati3_.id as exploitati3_id,
exploitati3_.name as exploitati3_name,
...
from request_requests request0_
inner join request_exploitation_sites exploitati1_ on request0_.id=exploitati1_.fk_request
left outer join request_activity activity2_ on request0_.fk_activity=activity2_.id
inner join request_exploitation_sites exploitati3_ on request0_.id=exploitati3_.fk_request
where lower(exploitati1_.dutch_name) like $1
or lower(exploitati1_.french_name) like $2
order by activity2_.dutch_name asc limit $3
use fetch in the first place and cast it to Join
Join<Object, Object> exploitationSites = (Join<Object, Object>) root.fetch("exploitationSites");
By casting the Fetch to a Join you can still use where clauses.
Note that this will also select additional columns, but won't do an additional join in the resulting query.
In both cases the fetch will result in a join fetch which hibernate internally will remove duplicates from the parent entity (see https://stackoverflow.com/a/51177569)
Update: look my answer below on how to check if 2 list intersects (both for #ElementCollection with string/enums and usual entities list mapped like #OneToMany)
I have an entity which contains #ElementCollectionfield with enums.
public enum StatusType {
NEW, PENDING, CLOSED;
}
#Entity
public class MyEntity {
#ElementCollection
#CollectionTable(name = "status_type", joinColumns = {#JoinColumn(name = "my_entity_id")})
#Column(name = "status_type", nullable = false)
private Set<StatusType > statusTypes = new HashSet<StatusType >();
...
}
Now I want to get all entities which contains status NEW or PENDING (or both).
I'm trying to use this query:
SELECT DISTINCT u FROM MyEntity u WHERE u.statusTypes in :statusTypes
But I'm getting exception: org.postgresql.util.PSQLException: No value specified for parameter 9.
How to properly query on collections and filter by intersections?
Problem solved by adding JOIN clause to HQL. Hibernate couldn't implicitly recognize that query needs JOIN clause. May be it will help someone:
SELECT DISTINCT u FROM MyEntity u
LEFT JOIN u.statusTypes statusTypes
WHERE statusTypes in :statusTypes
I set the query params like this:
query.setParameter( "statusTypes", listOfStatusTypesEnums);
It will select rows where at least one element of listOfStatusTypesEnums list is present in entity's statusTypes property (i.e. if 2 list are intersects in some way).
If you have usual list of entities (which are not #ElementCollection, but #OneToMany etc), same rule will work as well. Just use like this: LEFT JOIN u.subEntities subEntities WHERE subEntities.id in :subEntityIds
I am trying to use the JPA CriteriaBuilder to generate a query for an entity called "TestContact" that has a many-to-many join with another entity called "SystemGroup" where the attribute for this join called "groups". The objective of the query is to retrieve records from the "TestContact" entity where the "groups" attribute is either in a list or is empty.
The code I'm using is as follows
public List<TestContact> findWithCriteriaQuery(List<SystemGroup> groups) {
CriteriaBuilder cb = em.getCriteriaBuilder();
CriteriaQuery<TestContact> cq = cb.createQuery(TestContact.class);
Root<TestContact> testContact = cq.from(TestContact.class);
cq.select(testContact);
Path<List<SystemGroup>> groupPath = testContact.get("groups");
// cq.where(groupPath.in(groups));
// cq.where(cb.isEmpty(groupPath));
cq.where(cb.or(cb.isEmpty(groupPath), groupPath.in(groups)));
TypedQuery<TestContact> tq = em.createQuery(cq);
return tq.getResultList();
}
The problem is this query only returns results where group is in the list "groups" but for some reason isn't also returning the results where group is empty (i.e. there is no entry in the join table)
If I change the where clause to cq.where(cb.isEmpty(groupPath)); then the query correctly returns the results where group is empty.
If I change the where clause to cq.where(groupPath.in(groups)); then the query correctly returns the results where the group is in the list "groups".
What I don't understand is why when I try to combine these two predicates using the CriteriaBuilder or method the results don't include the records where the group is either in the list or is empty.
The groups attribute in the "TestContact" entity is declared as follows
#ManyToMany(fetch=FetchType.EAGER)
#JoinTable(name = "TEST_CONTACT_GROUPS", joinColumns = { #JoinColumn(name = "CONTACT_ID", referencedColumnName = "CONTACT_ID") }, inverseJoinColumns = { #JoinColumn(name = "GROUP_ID", referencedColumnName = "GROUP_ID") })
private List<SystemGroup> groups;
The JPA provider is EclipseLink 2.5.0, the Java EE application server is GlassFish 4 and the database is Oracle 11gR2.
Can anyone please point out where I'm going wrong?
Update
I've tried the suggestion from #Chris but Eclipse is returning the following error on Join<List<SystemGroup>> groupPath = testContact.join("groups", JoinType.LEFT)
Incorrect number of arguments for type Join; it cannot be
parameterized with arguments >
Looking at the JavaDoc for Join it says the type parameters are...
Z - the source type of the join, X - the target type of the join
I've tried Join<TestContact, SystemGroup> groupPath = testContact.join("groups", JoinType.LEFT); which then causes Eclipse to return the following error on cb.isEmpty
Bound mismatch: The generic method isEmpty(Expression) of type
CriteriaBuilder is not applicable for the arguments
(Join). The inferred type SystemGroup is not
a valid substitute for the bounded parameter >
The testContact.get("groups"); clause forces an inner join from testContact to groups, which filters out testContacts with no groups. You need to specify a left outer join, and use that in your isEmpty and in clauses.
Root<TestContact> testContact = cq.from(TestContact.class);
cq.select(testContact);
Join<TestContact, SystemGroup> groupPath = testContact.join("groups", JoinType.LEFT);
cq.where(cb.or(cb.isEmpty(testContact.get("groups")), groupPath.in(groups)));
I usually refer to https://en.wikibooks.org/wiki/Java_Persistence/Criteria#Join for examples
I am using Spring Data JpaRepository and I find it extremely easy to use. I actually need all those features - paging, sorting, filtering. Unfortunately there is one little nasty thing that seems to force me to fall back to use of plain JPA.
I need to order by a size of associated collection. For instance I have:
#Entity
public class A{
#Id
private long id;
#OneToMany
private List<B> bes;
//boilerplate
}
and I have to sort by bes.size()
Is there a way to somehow customize the ordering still taking the advantage of pagination, filtering and other Spring Data great features?
I've solved the puzzle using hints and inspirations from:
Limiting resultset using #Query anotations by Koitoer
How to order by count() in JPA by MicSim
Exhaustive experiments on my own
The first and most important thing I've not been aware of about spring-data is that even using #Query custom methods one can still create paging queries by simply passing the Pageable object as parameter. This is something that could have been explicitely stated by spring-data documentation as it is definitely not obvious though very powerful feature.
Great, now the second problem - how do I actually sort the results by size of associated collection in JPA? I've managed to come to a following JPQL:
select new package.AwithBCount(count(b.id) as bCount,c) from A a join a.bes b group by a
where AwithBCount is a class that the query results are actually mapped to:
public class AwithBCount{
private Long bCount;
private A a;
public AwithBCount(Long bCount, A a){
this.bCount = bCount;
this.a = a;
}
//getters
}
Excited that I can now simply define my repository like the one below
public interface ARepository extends JpaRepository<A, Long> {
#Query(
value = "select new package.AwithBCount(count(b.id) as bCount,c) from A a join a.bes b group by a",
countQuery = "select count(a) from A a"
)
Page<AwithBCount> findAllWithBCount(Pageable pageable);
}
I hurried to try my solution out. Perfect - the page is returned but when I tried to sort by bCount I got disappointed. It turned out that since this is a ARepository (not AwithBCount repository) spring-data will try to look for a bCount property in A instead of AwithBCount. So finally I ended up with three custom methods:
public interface ARepository extends JpaRepository<A, Long> {
#Query(
value = "select new package.AwithBCount(count(b.id) as bCount,c) from A a join a.bes b group by a",
countQuery = "select count(a) from A a"
)
Page<AwithBCount> findAllWithBCount(Pageable pageable);
#Query(
value = "select new package.AwithBCount(count(b.id) as bCount,c) from A a join a.bes b group by a order by bCount asc",
countQuery = "select count(a) from A a"
)
Page<AwithBCount> findAllWithBCountOrderByCountAsc(Pageable pageable);
#Query(
value = "select new package.AwithBCount(count(b.id) as bCount,c) from A a join a.bes b group by a order by bCount desc",
countQuery = "select count(a) from A a"
)
Page<AwithBCount> findAllWithBCountOrderByCountDesc(Pageable pageable);
}
...and some additional conditional logic on service level (which could be probably encapsulated with an abstract repository implementation). So, although not extremely elegant, that made the trick - this way (having more complex entities) I can sort by other properties, do the filtering and pagination.
One option, which is much simpler than the original solution and which also has additional benefits, is to create a database view of aggregate data and link your Entity to this by means of a #SecondaryTable or #OneToOne.
For example:
create view a_summary_view as
select
a_id as id,
count(*) as b_count,
sum(value) as b_total,
max(some_date) as last_b_date
from b
Using #SecondaryTable
#Entity
#Table
#SecondaryTable(name = "a_summary_view",
pkJoinColumns = {#PrimaryKeyJoinColumn(name = "id", referencedColumnName= "id")})
public class A{
#Column(table = "a_summary_view")
private Integer bCount;
#Column(table = "a_summary_view")
private BigDecimal bTotal;
#Column(table = "a_summary_view")
private Date lastBDate;
}
You can now then sort, filer, query etc purely with reference to entity A.
As an additional advantage you have within your domain model data that may be expensive to compute in-memory e.g. the total value of all orders for a customer without having to load all orders or revert to a separate query.
Thank you #Alan Hay, this solution worked fine for me. I just had to set the foreignKey attribute of the #SecondaryTable annotation and everything worked fine (otherwise Spring Boot tried to add a foreignkey constraint to the id, which raise an error for a sql View).
Result:
#SecondaryTable(name = "product_view",
pkJoinColumns = {#PrimaryKeyJoinColumn(name = "id", referencedColumnName = "id")},
foreignKey = #javax.persistence.ForeignKey(ConstraintMode.NO_CONSTRAINT))
I don't know much about Spring Data but for JPQL, to sort the objects by size of associated collection, you can use the query
Select a from A a order by a.bes.size desc
You can use the name of an attribute found in the select clause as a sort property:
#Query(value = "select a, count(b) as besCount from A a join a.bes b group by a", countQuery = "select count(a) from A a")
Page<Tuple> findAllWithBesCount(Pageable pageable);
You can now sort on property besCount :
findAllWithBesCount(PageRequest.of(1, 10, Sort.Direction.ASC, "besCount"));
I used nativeQuery to arrange sorting by number of records from another table, pagable works.
#Query(value = "SELECT * FROM posts where posts.is_active = 1 and posts.moderation_status = 'ACCEPTED' " +
"group by posts.id order by (SELECT count(post_id) FROM post_comments where post_id = posts.id) desc",
countQuery = "SELECT count(*) FROM posts",
nativeQuery = true)
Page <Post> findPostsWithPagination(Pageable pageable);
For SpringBoot v2.6.6, accepted answer isn't working if you need to use pageable with child's side field especially when using #ManyToOne.
For the accepted answer:
You can return new object with static query method, which have to include order by count(b.id)
And also order by bCount isn't working.
Please use #AlanHay solution, it is working, but you can't use primitive field and change foreign key constraint. For instance, change long with Long. Because:
When saving a new entity Hibernate does think a record has to be written to the secondary table with a value of zero. (if you use primitive type)
Otherwise you will get an exception:
Caused by: org.postgresql.util.PSQLException: ERROR: cannot insert into view "....view"
Here is the example:
#Entity
#Table(name = "...")
#SecondaryTable(name = "a_summary_view,
pkJoinColumns = {#PrimaryKeyJoinColumn(name = "id",
referencedColumnName= "id")},
foreignKey = #javax.persistence.ForeignKey(name = "none"))
public class UserEntity {
#Id
private String id;
#NotEmpty
private String password;
#Column(table = "a_summary_view",
name = "b_count")
private Integer bCount;
}
We have a DB table that is mapped into a hibernate entity. So far everything goes well...
However what we want is to only map enentitys that satisty a specific criteria, like ' distinct(fieldA,fieldB) '...
Is it possible to map with hibernate and hibernate annotations? How can we do it? With #Filter?
I would recommend that you use #Where annotation. This annotation can be used on the element Entity or target entity of a collection. You provide a clause attribute written in sql that will be applied to any select that hibernate performs on that entity. It is very easy to use and very readable.
Here is an example.
#Entity
//I am only interested in Donuts that have NOT been eaten
#Where(clause = "EATEN_YN = 'N'")
public class Donut {
#Column(name = "FILLING")
private String filling;
#Column(name = "GLAZED")
private boolean glazed = true;
#Column(name = "EATEN_YN")
private boolean eaten = false;
...
}
You could create a view and then map that view to entity:
create view my_data as
select ... from ...
#Entity(table="my_data")
public class MyData { ... }
One option is to map the table normally, then you could fetch your always entities through a query or a filter.
You could also make a native SQL query and map the entity on the results:
Query q = sess.createSQLQuery("SELECT DISTINCT fieldA, fieldB FROM some_table")
.addEntity(MyEntity.class);
List<MyEntity> cats = q.list();
It might be also possible to add DISTINCT to this type of HQL query:
select new Family(mother, mate, offspr)
from DomesticCat as mother
join mother.mate as mate
left join mother.kittens as offspr
Methods 1, 3 and 4 will make a read-only mapping.
Could you be more specific about the criteria you are using? The view approach is more generic since you can't do everything with a hibernate query or filter.
perhaps you could create a new Pojo that encapsulates the fields and the condition that they should statisy . And then then make that class a 'custom user defined type', such that Hibernate will have to use the mapping class that you provide, for mapping that 'type'..
In addition to the options mentioned by Juha, you can also create an object directly out of a SQL query using the NamedNativeQuery and SqlResultSetMapping annotations.
#Entity
#SqlResultSetMapping(name = "compositekey", entities =
#EntityResult(entityClass = MiniBar.class,
fields = { #FieldResult(name = "miniBar", column = "BAR_ID"), })
)
#NamedNativeQuery(name = "compositekey",
query = "select BAR_ID from BAR", resultSetMapping = "compositekey")
#Table(name = "BAR")
public class Bar {
Flavor the SQL query to your taste