Batch deletes via SQL cascade delete

Author: AnghelLeonard

HibernateSpringBootBatchDeleteCascadeDelete/src/main/java/com/bookstore/repository/AuthorRepository.java

@@ -1,9 +1,18 @@
 package com.bookstore.repository;
 
 import com.bookstore.entity.Author;
+import java.util.List;
+import javax.persistence.QueryHint;
+import static org.hibernate.jpa.QueryHints.HINT_PASS_DISTINCT_THROUGH;
 import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Query;
+import org.springframework.data.jpa.repository.QueryHints;
 import org.springframework.stereotype.Repository;
 
 @Repository
 public interface AuthorRepository extends JpaRepository<Author, Long> {
+
+    @QueryHints(value = @QueryHint(name = HINT_PASS_DISTINCT_THROUGH, value = "false"))
+    @Query(value = "SELECT DISTINCT a FROM Author a JOIN FETCH a.books b WHERE a.age < ?1")
+    List<Author> fetchAuthorsAndBooks(int age);
 }

HibernateSpringBootBatchDeleteCascadeDelete/src/main/java/com/bookstore/service/BookstoreService.java

@@ -26,7 +26,7 @@ public void batchAuthorsAndBooks() {
             Author author = new Author();
             author.setName("Name_" + i);
             author.setGenre("Genre_" + i);
-            author.setAge(18 + i);
+            author.setAge((int) ((Math.random() + 0.1) * 100));
 
             for (int j = 0; j < 5; j++) {
                 Book book = new Book();