Question

I have ManyToMany relationship between Author and Book.
table :AUTHOR
id | name

table :ASSIGN
*id | author_id | book_id*

table : BOOK
id | title

But I am using not standart ManyToMany mapping, I am using next

class Book
{
   @Id
   long id;

   String title;

   @OneToMany
   List<Assign> authors;
}

class Assign
{
   @Id
   long id;

   @ManyToOne
   Book book

   @ManyToOne
   Author author;
}

class Author
{
   @Id
   long id;

   String name;

   @OneToMany
   List<Assign> books;
}  

What is query to get all Books for Author’s name? Also What is query to get all Books’ names for Author’s name?

Answer 1

You simply have two OneToMany associations. You just need to use joins in your query, as described in the Hibernate documentation over HQL.

select book from Author author 
left join author.books assign
left join assign.book book
where author.name = :name

The second query is the same, except you just want the book names:

select book.name from Author author ...

Side note: you shouldn’t name your collection of Assigns books or authors: it’s very confusing. Name it assigns.