CODEWITHSUNDEEP
javahibernatespring-data-jpaone-to-manyspring-repositories
ip696
ip696

Reputation: 7084

Curectly save OneToMany entity if parent has not ID

I have 2 entities:

@Data
@AllArgsConstructor
@NoArgsConstructor
@ToString(exclude = "products")
@Entity
@Table(name = "categories")
public class Category {
  @Id
  @GeneratedValue(strategy = GenerationType.AUTO)
  private Long id;
  private String categoryName;
  private String categoryType;
  @OneToMany(mappedBy = "category", cascade = CascadeType.ALL)
  private List<Product> products;
}

and second entity:

@Data
@AllArgsConstructor
@NoArgsConstructor
@Entity
@Table(name = "products")
public class Product {
  @Id
  @GeneratedValue(strategy = GenerationType.AUTO)
  private Long id;
  private String productName;
  private String productDescription;
  @ManyToOne()
  private Category category;
}

And I have 2 repository for each entity:

@Repository
public interface ProductRepository extends JpaRepository<Product, Long> {
}

@Repository
public interface CategoryRepository extends JpaRepository<Category, Long> {
}

Then I send this JSON to cintroller and I heed save all Product:

{
    "products": [{
        "productName": "product1",
        "productDescription": "productDescription1",
        "category": {
            "categoryName": "catName1",
            "categoryType": "type1"
        }
    },
    {
        "productName": "product2",
        "productDescription": "productDescription2",
        "category": {
            "categoryName": "catName1",
            "categoryType": "type1"
        }
    },
    {
        "productName": "product3",
        "productDescription": "productDescription3",
        "category": {
            "categoryName": "catName2",
            "categoryType": "type2"
        }
    }]
}

And Then I need save it:

@PostMapping(value = "test")
public Category test(@RequestBody() RequestTest products) {

  List<Product> productList = products.getProducts();
  for (Product product : productList) {
  //save all
  }
}

category not have id and when I get this JSON I need create all products and set category, but I have not category id and if I do next:

for (Product product : productList) {
      Category category = product.getCategory();
      Category save = categoryRepository.save(category);
      product.setCategory(save);
      productRepository.save(product);
}

I create new ctegore for each product and I get this:

49  catName1    type1
51  catName1    type1
53  catName2    type2
                                        cat_id
50  productDescription1 product1        49
52  productDescription2 product2        51
54  productDescription3 product3        53

but I need:

49  catName1    type1
51  catName2    type2
                                        cat_id
50  productDescription1 product1        49  
52  productDescription2 product2        49  
54  productDescription3 product3        51

Upvotes: 0

Views: 194

Answers (3)

Ramesh Fadatare
Ramesh Fadatare

Reputation: 589

First insert all the unique categories and check for same exist in database. Make sure categories should be unique.

Upvotes: 0

Maciej Kowalski
Maciej Kowalski

Reputation: 26522

In my opinion the best way would be to keep track of saved categories by introducing a Map.

Assuming that categoryName is a unique column then you could do something following:

Map<String,Category> categoryMap = new HashMap<>();

for (Product product : productList) {
      String categoryName = product.getCategory().getCategoryName(); 
      Category category = categoryMap.get(categoryName);

      if(category == null){
         category = categoryRepository.save(product.getCategory());
         categoryMap.put(categoryName,category);
      }       

      product.setCategory(save);
      productRepository.save(product);
}

Upvotes: 1

Ashish Mathew
Ashish Mathew

Reputation: 823

You might want to find first if the category object already exists.

You could create a query that searches if a category exists by the same name and type. If it exists, use that object, which will have the ID too, or else go on with your current code.

Upvotes: 1

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