OneToMany无法确定SpringBoot / SQLite3的类型

Question

我对关系oneToMany有疑问。我在SQLite数据库中创建了表，这是我的表： 我创建了两个模型CategoryModel和ProductModel。 ProductModel是：

@Entity
@Table(name = "Product_Category")
@JsonIgnoreProperties({ "hibernateLazyInitializer", "handler" })
public class ProductModel {

    @Id
    @Column(name = "id")
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long product_id;
    private Long category_id;

    private String name;
    private String description;
    private int numberOfProduct;
    private String image;
    private int price;

    @JoinColumn(name = "country_id", nullable = false)
    private CategoryModel category;

    //geter's and seter's
}

我的CategoryModel：

@Entity
@Table(name = "Category")
@JsonIgnoreProperties({ "hibernateLazyInitializer", "handler" })
public class CategoryModel {
    @Id
    @Column(name = "id")
    @GeneratedValue(strategy = GenerationType.AUTO)
    private int id;

    private String category_name;
    private String category_description;
    private String image_path;

    @OneToMany( mappedBy = "category")
    private Set<ProductModel> category;
  //Geter's and Seter's

我的存储库：

public interface CategoryRepository extends JpaRepository<CategoryModel, Long>  {

    @Query("SELECT * "
            + "FROM Product_Category d INNER JOIN d.categoryModel e")
    List<ProductModel> fetchEmpDeptDataInnerJoin();

}

我不明白我在哪里犯错。我遇到此错误：

  

无法确定以下类型：   com.dar.darkozmetika.models.CategoryModel，在表格上：product_category，   对于列：[org.hibernate.mapping.Column（category）]

Answer 1

1）：添加@ManyToOne批注：

@ManyToOne
@JoinColumn(name = "country_id", nullable = false)
private CategoryModel category;

2）请记住，您使用的是JPQL，而不是SQL（除非您发送了native="true"）：

   @Query("SELECT p "
        + "FROM ProductModel p INNER JOIN p.category c")