引起：org.postgresql.util.PSQLException：错误：

Question

我正在开发 Spring Data JPA Postgres 示例。在这个例子中，我建立了 Student 和 StudentMember 之间的关系。Student.java@Builder@Data@AllArgsConstructor@NoArgsConstructor@Entity@Table(uniqueConstraints = {        @UniqueConstraint(name="student_name_key",columnNames = {"studentName"})})public class Student{    @Id    @GeneratedValue(strategy = GenerationType.IDENTITY)    @Column(name = "studentId")    private Long studentId;    @Column(name = "studentName", nullable = false)    private String studentName;    @OneToMany(mappedBy = "student", fetch = FetchType.LAZY, cascade = CascadeType.ALL)    private List<StudentMember> studentMembers;}StudentMember.java@Builder@Data@AllArgsConstructor@NoArgsConstructor@Entity@Tablepublic class StudentMember {    @Id    @GeneratedValue(strategy = GenerationType.IDENTITY)    private Long studentMemberId;    @ManyToOne(fetch = FetchType.LAZY)    @JoinColumn(name="studentId", insertable=false, updatable=false, nullable = false,foreignKey=@ForeignKey(name = "fk_student_id"))    private Student student;}MainApp.java@SpringBootApplicationpublic class MyProgramApplication implements CommandLineRunner {    @Autowired    ProgramMemberRepository memberRepository;    @Autowired    ProgramRepository programRepository;    public static void main(String[] args) {        SpringApplication.run(MyProgramApplication.class, args);    }    @Override    public void run(String... args) throws Exception {        Student student = Student.builder().studentName("John Doe").build();        programRepository.save(student);        StudentMember programMember = StudentMember.builder()                .student(student)                .build();        if(Objects.nonNull(student.getStudentMembers())){            student.getStudentMembers().add(programMember);        }

Answer 1

您Student在实体中的关系StudentMember是只读的。

消除insertable=false, updatable=false

@ManyToOne(fetch = FetchType.LAZY)

@JoinColumn(name="studentId", nullable = false,foreignKey=@ForeignKey(name = "fk_student_id"))

private Student student;

否则 Hibernate 不写入外键。

另外我不确定你的映射是否正确。PostgreSQL 抱怨一个列被调用student_id但名称@JoinColum是studentId

先检查这个。