anghelleonard/hibernate-springboot

Collection of 300+ best practices for Java persistence performance in Spring Boot applications

hibernate-springboot's Issues

duplicate records fetched while using findall method with specification and payable

I'm seeing some weird issue while working with findAll() method with the specification and pageable arguments. If I set the lower page i.e. 0 size i.e. 10 then I don't have any issues. but if I set the page i.e. 0 and size to 30 I'm getting the duplicate records.

e.g.

ID	NAME
1	test
2	test
3	test
4	test
5	test
6	test
7	test
8	test
9	test
1	test
2	test
3	test
4	test
11	test
6	test
7	test
18	test

I have the following in the database.

ID	NAME
1	test
2	test
3	test
4	test
5	test
6	test
7	test
8	test
9	test
10	test
11	test
12	test
13	test
14	test
15	test
16	test
17	test
18	test

@Entity
@Table(name = "table_name")
@JsonIgnoreProperties(ignoreUnknown = true)
@DynamicUpdate
public class Emp implements Persistable<String> {

    @Id
    @Column(name = "emp_id", nullable = false, columnDefinition = "BINARY(16)")
    public String empId;
    
    @Column(name = "name");
    public String name;
    // other fields
    
    //setters and getters
    
}

@Repository
public interface EmpRepository extends JpaRepository<Emp, String> {
    Page<Emp> findAll(Specification<Emp> specification, Pageable page);
}

public class EmpSpecification {
    public static Specification<Emp> nameEquals(String name) {
        return (root, query, builder) -> name == null ? null : builder.equal(root.get("name"), name);
    }
}

in the service class we are trying to fetch data using the following code:

Specification<Emp> specifications = Specification.where(EmpSpecification.nameEquals(name)));
details = consolidatedTradeSummaryRepository.findAll(specifications, page);

http://localhost:8080/emp?name=test&page=0&size=10
http://localhost:8080/emp?name=test&page=0&size=20

Spring boot version : 2.2.2.RELEASE

HibernateSpringBootLeftJoinFetch/README.md error

Similar, we can fetch all Book, including those with no registered Author. This can be done via JOIN FETCH or **JOIN**.
JOIN didn't return all Book. The result excluding the record when the author_id is null.

HibernateSpringBootOneToManyBidirectional has issue with removeBooks method

Hi,

Thanks for awesome book.

HibernateSpringBootOneToManyBidirectional has helper method removeBooks.

    @Transactional
    public void deleteAllBooksOfAuthor() {
        Author author = authorRepository.findByName("Joana Nimar");
        author.removeBooks(); // use removeBooks() helper    
    }

But if you see carefully, it calls delete for each book entity. Can we optimize it somehow to call like IN queries instead?

Also purpose of these helper methods is to call on managed entities or detached ones only?

Interesting, I am using the same approach but still duplicated records

I am using findAll(Specification, Pageable) with hints, but the result still contains duplicated records.

Hibernate 5.3.x
Postgres 9.6

Extra queries on @OneToOne relation with lazy fetch type

I tried the example with the hibernate-enhance-maven-plugin activated, and confirmed that direct @OnetoOne relations were being lazily loaded. I created a Book class with a @OnetoOne to Author, and every time I fetched a book, the author was being fetched lazily:

select book0_.id as id1_1_0_, book0_.author as author2_1_0_ from book book0_ where book0_.id=?

However, when I fetch an Author, which has an inverse @OnetoOne relation with Book, an extra query is being excecuted:

select author0_.id as id1_0_0_, author0_.age as age2_0_0_, author0_.avatar as avatar3_0_0_, author0_.genre as genre4_0_0_, author0_.name as name5_0_0_ from author author0_ where author0_.id=?
select book0_.id as id1_1_0_, book0_.author as author2_1_0_ from book book0_ where book0_.author=?  // <-- This shouldn't be fetched

I read that this happens because hibernate does not know if it has to create a proxy or load it with a null reference, but I thought that the enhancement plugin fixed this.

This is the book class I created:

@Entity
public class Book implements Serializable {
    private static final long serialVersionUID = 2L;

    @Id
    public Long id;

    @OneToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "author")
    public Author author;
}

and the author class is the same as in the example, but I added the inverse relation:

@OneToOne(mappedBy = "author", fetch = FetchType.LAZY)
Book book;

Is there an error in my tests or it's still a limitation in the library? How are we suposed to solve this problem? Since if I fetch a list of objects with inverse relations, I will be making several extra queries and it will negatively impact on the performance

Forgot to mention: I also tried using @LazyToOne and @LazyGroup annotations in each field, but had the same results.