ERROR: null value in column "id" of relation xxx violates not-null constraint - Spring Data JPA

Question

我对来自 Spring JPA 的 @GeneratedValue 注释有疑问。

这是我的 class:

@Entity
@NoArgsConstructor
@Getter
@Setter
public class Product {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    private String name;
    private Double price;
    private Integer quantity;

    @ManyToOne
    private Category category;

    @ManyToOne
    private Manufacturer manufacturer;



    public Product(String name, Double price, Integer quantity, Category category, Manufacturer manufacturer) {
        this.name = name;
        this.price = price;
        this.quantity = quantity;
        this.category = category;
        this.manufacturer = manufacturer;
    }
}

当我尝试添加新产品时出现此错误：

2021-12-06 18:03:02.013 ERROR 3720 --- [nio-9090-exec-3] o.h.engine.jdbc.spi.SqlExceptionHelper   : ERROR: null value in column "id" of relation "product" violates not-null constraint
  Detail: Failing row contains (null, Dress, 333, 33, 1, 1).
2021-12-06 18:03:02.028 ERROR 3720 --- [nio-9090-exec-3] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.dao.DataIntegrityViolationException: could not execute statement; SQL [n/a]; constraint [id" of relation "product]; nested exception is org.hibernate.exception.ConstraintViolationException: could not execute statement] with root cause

org.postgresql.util.PSQLException: ERROR: null value in column "id" of relation "product" violates not-null constraint
  Detail: Failing row contains (null, Dress, 333, 33, 1, 1).

这是我的服务的保存方法 class:

@Override
    public Optional<Product> save(String name, Double price, Integer quantity, Long categoryId, Long manufacturerId) {
        Category category = this.categoryRepository.findById(categoryId).orElseThrow(() -> new CategoryNotFoundException(categoryId));
        Manufacturer manufacturer = this.manufacturerRepository.findById(manufacturerId).orElseThrow(() -> new ManufacturerNotFoundException(manufacturerId));

        this.productRepository.deleteByName(name);

        return Optional.of(this.productRepository.save(new Product(name, price, quantity, category, manufacturer)));
    }

老实说，我不知道这是怎么发生的。我在某处读到 PostgreSQL 不支持 GenerationType.IDENTITY，但我不认为是这样，因为我对 Category 和 Manufacturer 使用了相同的生成类型 tables，我可以毫无问题地向它们添加新的元组。我尝试使用生成类型 SEQUENCE 并且 它有效 ，但我不想使用该生成类型并且我不明白为什么 IDENTITY 在这里不起作用 当它对 table 的其他人有效时。有什么想法吗？

编辑 1： 使用 GenerationType.AUTO 对其进行了测试并且它有效，但对于类型 IDENTITY 仍然显示相同的错误。

编辑 2： 共享 SQL 以创建产品 table 和类别 table。

CREATE TABLE IF NOT EXISTS public.product
(
    id bigint NOT NULL,
    name character varying(255) COLLATE pg_catalog."default",
    price double precision,
    quantity integer,
    category_id bigint,
    manufacturer_id bigint,
    CONSTRAINT product_pkey PRIMARY KEY (id),
    CONSTRAINT fk1mtsbur82frn64de7balymq9s FOREIGN KEY (category_id)
        REFERENCES public.category (id) MATCH SIMPLE
        ON UPDATE NO ACTION
        ON DELETE NO ACTION,
    CONSTRAINT fkq5vxx1bolpwm1sngn6krtwsjn FOREIGN KEY (manufacturer_id)
        REFERENCES public.manufacturers (id) MATCH SIMPLE
        ON UPDATE NO ACTION
        ON DELETE NO ACTION
)

TABLESPACE pg_default;

ALTER TABLE public.product
    OWNER to wp;

CREATE TABLE IF NOT EXISTS public.category
(
    id bigint NOT NULL DEFAULT nextval('category_id_seq'::regclass),
    description character varying(4000) COLLATE pg_catalog."default",
    name character varying(255) COLLATE pg_catalog."default",
    CONSTRAINT category_pkey PRIMARY KEY (id)
)

TABLESPACE pg_default;

ALTER TABLE public.category
    OWNER to wp;

最终编辑： 我的问题已得到解答，由于某种原因我的主键未设置为自动递增，这导致了问题。我相信这是因为我只用 @Id 注释创建了 table 并且在创建它之后我添加了生成策略（没有将 id 设置为自动递增。

Answer 1

要使其正常工作，您必须更改产品中的某些内容 table。

@GeneratedValue(strategy = GenerationType.IDENTITY) 只有在您的 ID 列是 SERIAL 类型时才有效。

检查 ID 列是否为该类型。示例：

CREATE TABLE Product(
    id SERIAL NOT NULL,
    name VARCHAR(20),
    etc...
)

ERROR: null value in column "id" of relation xxx violates not-null constraint - Spring Data JPA

ERROR: null value in column "id" of relation xxx violates not-null constraint - Spring Data JPA

java

postgresql

spring-data

spring-data-jpa

spring-boot