How to join a table with a selection using CriteriaBuilder?
Suppose I have this query:
SELECT
tbl1.*,
tbl2.total
FROM
table_1 tbl1
LEFT JOIN
(SELECT col_id AS id, SUM(value) AS total FROM table_2 WHERE active = 1 GROUP BY col_id) tbl2
ON
tbl1.id = tbl2.id;
Where the definition of table_1 is:
CREATE TABLE table_1(
id NUMBER(19, 0),
-- other columns
)
... and table_2 ...
CREATE TABLE table_2(
id NUMBER(19, 0),
col_id NUMBER(19, 0),
value NUMBER(14, 2),
-- other columns
FOREING KEY (col_id) REFERENCES table_1(id);
)
This is not possible with plain JPA or Hibernate. With Hibernate you can model this query if the subquery is static, but for dynamic subqueries you will need something like Blaze-Persistence which works on top of JPA/Hibernate and provides support for these things.
For the static query solution you can do this:
#Entity
#Table(name = "table1")
public class Table1 {
#Column(name = "id")
private Integer id;
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "id", insertable = false, updatable = false)
private Table2 table2;
}
#Entity
#Subselect("SELECT col_id AS id, SUM(value) AS total FROM table_2 WHERE active = 1 GROUP BY col_id")
public class Table2Query {
#Column(name = "id")
private Integer id;
#Column(name = "total")
private BigDecimal total;
}
Here is a nice article by Vlad Mihalcea about Blaze-Persistence if you want a dynamic solution i.e. where the query structure isn't fixed: https://vladmihalcea.com/blaze-persistence-jpa-criteria-queries/
Use the join method in root and use it to get the values from the other table.
Note: you need to add the relation in the entity depending on the relationship of these tables (onetone, manytoone or onetomany). Something like this:
Entity code Table1:
#OneToOne
private Table2 table2;
Search code example:
(Root<Table1> root, CriteriaQuery<?> query, CriteriaBuilder cb) -> {
Join<Table1, Table2> joinTable2 = root.join("table2");
cb.equal(joinTable2.get("active"), 1);
.. other filters ..
};
Related
I'm getting what I think are needless CROSS JOINs when I'm doing a select IN SUBQUERY, which is hurting performance. I'm using Postgres if that makes a difference.
I'm aiming to generate the following query
select a1.first_name from author a1
where a1.last_name = ?
and (a1.id in
(select distinct b.author_id
from book b
where (b.published_on between ? and ?)
group by b.author_id
having count(b.author_id) >= 2))
But I get
select a1.first_name from author a1
where a1.last_name = ?
and (a1.id in
(select distinct b.author_id
from book b
cross join author a2 where b.author_id = a2.id -- <<< I don't want this cross join!
and (b.published_on between ? and ?)
group by b.author_id
having count(b.author_id) >= 2))
Code
CriteriaBuilder cb = entityManager.getCriteriaBuilder();
CriteriaQuery<String> cq = cb.createQuery(Author.class);
Root<Author> authorRoot = cq.from(Author.class);
Subquery<Long> countSubquery = cq.subquery(Long.class);
Root<Book> bookRoot = countSubquery.from(Book.class);
Expression<Long> count = cb.count(bookRoot.get(Book_.author));
countSubquery.select(bookRoot.get(Book_.AUTHOR))
.distinct(true)
.where(cb.between(bookRoot.get(Book_.publishedOn),
LocalDate.of(2021, MARCH, 1),
LocalDate.of(2021, MARCH, 31)))
.groupBy(bookRoot.get(Book_.author))
.having(cb.greaterThanOrEqualTo(count, 2L));
cq.where(
cb.equal(authorRoot.get(Author_.lastName), "Smith"),
cb.in(authorRoot.get(Author_.ID)).value(countSubquery));
cq.select(authorRoot.get(Author_.FIRST_NAME));
TypedQuery<String> query = entityManager.createQuery(cq);
return query.getResultList();
In reality I'm generating the queries from a user driven query builder, this code recreates the exact problem I'm having.
When using the query builder the user could end up with multiple select in subqueries so I need this to perform as well as possible.
I don't see why I should need any join/cross join for my query to work.
Entities
#Entity
public class Author {
#Id
#GeneratedValue
private Long id;
private String firstName;
private String lastName;
#OneToMany(mappedBy = "author", cascade = CascadeType.ALL, fetch = FetchType.LAZY)
private Set<Book> books;
}
#Entity
public class Book {
#Id
#GeneratedValue
private Long id;
private String name;
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "author_id")
private Author author;
private LocalDate publishedOn;
}
This expression: bookRoot.get(Book_.author) means you're joining Author to Book implicitly.
To get rid of the extra join, you would have to either use a native query, or map Book.author_id once more as a simple column:
#Column(name = "author_id", insertable = false, updatable = false)
private Long authorId;
And use Book_.authorId instead.
The below code snippet does not work:
#Id
private Long id;
#ManyToMany(fetch = FetchType.LAZY)
#JoinFormula("""
(SELECT DISTINCT ON (product11.id, text26.language, textsourced28.source) text26.id
FROM product AS product11
JOIN producttexttitle AS producttexttitle27 ON product11.id = producttexttitle27.product
JOIN text AS text26 ON producttexttitle27.text = text26.id
JOIN textsourced AS textsourced28 ON text26.id = textsourced28.text
WHERE product11.id=id
ORDER BY product11.id, text26.language, textsourced28.source, textsourced28.time DESC)
""")
private List<Text> titles;
However this does,
#Id
private Long id;
#ManyToOne(fetch = FetchType.LAZY)
#JoinFormula("""
(SELECT DISTINCT ON (product11.id, text26.language, textsourced28.source) text26.id
FROM product AS product11
JOIN producttexttitle AS producttexttitle27 ON product11.id = producttexttitle27.product
JOIN text AS text26 ON producttexttitle27.text = text26.id
JOIN textsourced AS textsourced28 ON text26.id = textsourced28.text
WHERE product11.id=id
ORDER BY product11.id, text26.language, textsourced28.source, textsourced28.time DESC
LIMIT 1)
""")
private Text titles;
The only problem is that the latter one only returns one instance, where I am looking for several.
Can figure it out.
#CollectionTable or #ElementCollection usage perhaps?
I need to supply a custom sql.
Our in-house framework built with Java 11, Spring Boot, Hibernate 5 and QueryDSL does a lot of auto-generation of queries. I try to keep everything efficient and load associations only when needed.
When loading full entities, the programmer can declare a NamedEntityGraph to be used. Now there is one case where a query like this is generated:
select user.groups
from User user
where user.id = ?1
Where the Entities in question look like this:
#Entity
#NamedEntityGraph(name = User.ENTITY_GRAPH,
attributeNodes = {
#NamedAttributeNode(User.Fields.permissions),
#NamedAttributeNode(value = User.Fields.groups, subgraph = "user-groups-subgraph")
},
subgraphs = #NamedSubgraph(
name = "user-groups-subgraph",
attributeNodes = {
#NamedAttributeNode(Group.Fields.permissions)
}
))
public class User {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#Enumerated(EnumType.STRING)
#ElementCollection(targetClass = Permission.class)
#CollectionTable(name = "USERS_PERMISSIONS", joinColumns = #JoinColumn(name = "uid"))
private Set<Permission> permissions = EnumSet.of(Permission.ROLE_USER);
#ManyToMany(fetch = LAZY)
private Set<Group> groups = new HashSet<>();
}
#Entity
#NamedEntityGraph(name = Group.ENTITY_GRAPH,
attributeNodes = {
#NamedAttributeNode(value = Group.Fields.permissions)
})
public class Group {
#Id
#GeneratedValue(strategy = GenerationType.SEQUENCE)
private Long id;
#Enumerated(EnumType.STRING)
#ElementCollection(targetClass = Permission.class)
#CollectionTable(
name = "GROUPS_PERMISSIONS",
joinColumns = #JoinColumn(name = "gid")
)
#NonNull
private Set<Permission> permissions = EnumSet.noneOf(Permission.class);
}
When selecting either User or Group directly, the generated query simply applies the provided NamedEntityGraphs. But for the above query the exception is:
org.hibernate.QueryException:
query specified join fetching, but the owner of the fetched association was not present in the select list
[FromElement{explicit,collection join,fetch join,fetch non-lazy properties,classAlias=user,role=foo.bar.User.permissions,tableName={none},tableAlias=permission3_,origin=null,columns={,className=null}}]
I first tried the User graph, but since we are fetching Groups, I tried the Group graph. Same Exception.
Problem is, there is no easy way to add a FETCH JOIN to the generated query, since I don't know which properties of the association should be joined in anyway. I would have to load the Entitygraph, walk it and any subgraph and generated the right join clauses.
Some more details on Query generation:
// QueryDsl 4.3.x Expressions, where propType=Group.class, entityPath=User, assocProperty=groups
final Path<?> expression = Expressions.path(propType, entityPath, assocProperty);
// user.id = ?1
final BooleanExpression predicate = Expressions.predicate(Ops.EQ, idPath, Expressions.constant(rootId));
// QuerydslJpaPredicateExecutor#createQuery from Spring Data JPA
final JPQLQuery<P> query = createQuery(predicate).select(expression).from(path);
// Add Fetch Graph
((AbstractJPAQuery<?, ?>) query).setHint(GraphSemantic.FETCH.getJpaHintName(), entityManager.getEntityGraph(fetchGraph));
EDIT:
I can reproduce this with a simple JPQL Query. It's very strange, if I try to make a typed query, it will select a List of Sets of Group and untyped just a List of Group.
Maybe there is something conceptually wrong - I'm selecting a Collection and I'm trying to apply a fetch join on it. But JPQL doesn't allow a SELECT from a subquery, so I'm not sure what to change..
// em is EntityManager
List gs = em
.createQuery("SELECT u.groups FROM User u WHERE u.id = ?1")
.setParameter(1, user.getId())
.setHint(GraphSemantic.FETCH.getJpaHintName(), em.getEntityGraph(Group.ENTITY_GRAPH))
.getResultList();
Same Exception:
org.hibernate.QueryException: query specified join fetching, but the owner of the fetched association was not present in the select list
So the problem can be distilled down to a resolution problem of the Entit Graphs attributes:
select user.groups
from User user
where user.id = ?1
With the Entity Graph
EntityGraph<Group> eg = em.createEntityGraph(Group.class);
eg.addAttributeNodes(Group.Fields.permissions);
Gives an Exception that shows that Hibernate tries to fetch User.permissions instead of Group.permissions. This is the bug report.
And there is another bug regarding the use of #ElementCollection here.
Good evening,
Let my pojo Athor be:
public class Author {
private long id;
private String name;
#JoinColumn(name = "id", nullable = false)
private Editor editor;
}
I'd like to know if is there any difference, like performance, executions, etc between this two JPQL queries using Hibernate:
select a.name, b.name from Author a inner join a.editor e where a.id = 1;
and
select a.name, a.editor.name from Athor a where a.id = 1;
Thanks!
I have two entities in MySQL as below. The primary key of nnm_tran is a composite of id and source. The primary key of bargains is actually a foreign key link to the nnm_tran table
I'm trying to use JPA inheritance to represent these.
nnm_tran entity
#Entity
#Table(name = "nnm_tran")
#IdClass(CommonTransactionKey.class)
#Inheritance(strategy = InheritanceType.JOINED)
#DiscriminatorColumn(name = "bargain_flag", discriminatorType = DiscriminatorType.CHAR)
#DiscriminatorValue("N")
public class CommonTransaction {
#Id
#Column(name = "id", nullable = false)
private String transactionId;
#Column(name = "plan_number", nullable = false)
private String planNumber;
#Column(name = "tran_date")
private LocalDateTime transactionDatetime;
#Column(name = "bargain_flag")
private String bargainFlag;
...
}
bargains entity
#Data
#EqualsAndHashCode(callSuper = true)
#Entity
#Table(name = "bargains")
#DiscriminatorValue("B")
#PrimaryKeyJoinColumns({ #PrimaryKeyJoinColumn(name = "nnm_tran_id", referencedColumnName = "id"), #PrimaryKeyJoinColumn(name = "nnm_tran_source", referencedColumnName = "source") })
public class Bargain extends CommonTransaction implements Serializable {
#Column(name = "unit_price")
private BigDecimal unitPrice;
#Column(name = "client_price")
private BigDecimal clientPrice;
...
}
I think so far this is all hooked up correctly. My problem comes when I attach a spring-data repository with a custom query.
Repository
public interface CommonTransactionRepository extends CrudRepository<CommonTransaction, CommonTransactionKey> {
#Query("select t from CommonTransaction t left join IoPlan p ON t.planNumber = p.planNumber "
+ "where (p.planNumber is NULL or p.planNumber = '') "
+ "and t.transactionDatetime between ?1 and ?2 "
+ "and t.cancelled = false")
public Iterable<CommonTransaction> findOrphanedTransactionsByTranDate(LocalDateTime fromDate, LocalDateTime toDate);
...
}
When this gets proxied and the method is executed it generates the SQL statement
SELECT DISTINCT nnm_tran.bargain_flag FROM nnm_tran t1 LEFT OUTER JOIN io_plan t0 ON (t1.plan_number = t0.plan_number) WHERE ((((t0.plan_number IS NULL) OR (t0.plan_number = ?)) AND (t1.tran_date BETWEEN ? AND ?)) AND (t1.CANCELLED = ?))
The issue with this is that the nnm_tran table is aliased to t1 but the discriminator column is referencing the full table name nnm_tran.bargain_flag The result is a lovely
UnitOfWork(17171249)--Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.5.2.v20140319-9ad6abd): org.eclipse.persistence.exceptions.DatabaseException
Internal Exception: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Unknown column 'nnm_tran.bargain_flag' in 'field list'
Question here is, am I doing something wrong or is this a bug in spring-data and/or eclipselink?
Versions: spring-data 1.7.2, Eclipselink 2.5.2, MySQL 5.6.28
Using #manish's sample app as a starting point I started layering back on the complexity that was missing and quickly stumbled across the thing causing the rogue SQL. It was down to the join I had performed in the JPQL
NOTE: If you've come here from the future then ignore the remainder of this answer and instead use #Chris's comment instead.
Most of the time I don't need to look at or even think about the IoPlan table that can be seen in the #Query
#Query("select t from CommonTransaction t left join IoPlan p ON t.planNumber = p.planNumber "
+ "where (p.planNumber is NULL or p.planNumber = '') "
+ "and t.transactionDatetime between ?1 and ?2 "
+ "and t.cancelled = false")
and so this table is not a part of the CommonTransaction entity as a field. Even the result of this query doesn't really care because it's looking only as a one off for CommonTransaction with no associated join in the IoPlan table.
When I added the join back in to the sample app from #manish it all broke in the same way my app has in EclipseLink, but broke in a different way for Hibernate. Hibernate requires a field for you to join with, which if you ask me defeats the purpose of writing the join in the #Query. In fact in Hibernate you have to define the join purely in JPA so you might as well then use dot notation to access it in the JPQL.
Anyway, going along with this idea I tried adding a dummy field to hold an IoPlan in my CommonTransaction entity and it almost worked. It defaulted some of the join logic but it was closer
SELECT DISTINCT t1.bargain_flag FROM nnm_tran t1 LEFT OUTER JOIN io_plan t0 ON ((t0.ID = t1.IOPLAN_ID) AND (t1.plan_number = t0.plan_number)) WHERE ((((t0.plan_number IS NULL) OR (t0.plan_number = ?)) AND (t1.tran_date BETWEEN ? AND ?)) AND (t1.CANCELLED = ?))
In this case t1.IOPLAN_ID and t0.ID don't exist. So I ended up defining the entire join in my CommonTransaction entity
#OneToOne
#JoinColumn(insertable = false, updatable = false, name = "plan_number", referencedColumnName = "plan_number")
private IoPlan ioPlan;
and voila, it started working. It's not pretty and now I have a redundant join condition
LEFT OUTER JOIN io_plan t1
ON ((t1.plan_number = t0.plan_number) AND (t0.plan_number = t1.plan_number))
but I can fix that. It's still annoying that I have to define a field for it whatsoever, I don't actually want or need it there, not to mention that the result from this query is returning CommonTransaction entities that have no IoPlan so the field will be permanently null.