唯一索引或主键冲突：“PUBLIC.STUDENT（STUDENT_ID）[0，NULL，NULL]上的主键”；SQL语句：

Question

尝试通过REST Post方法插入学生对象时出现以下错误

2020-10-08 18:50:08.799错误21708---[nio-8080-exec-7]o. a. c. c.C.[.[.]Servlet.service（）的servlet[调度Servlet]在上下文中的路径[]抛出异常[请求处理失败；嵌套异常是org.springframework.dao.数据完整性违反异常：不能执行语句；SQL[n/a]；约束["学生（STUDENT_ID）[0， NULL， NULL]”；SQL语句：插入学生（class_id，student_name，student_id）值 (?, ?, ?)[23505-200]]；嵌套异常是org.hibernate.exception.ConstraintViolation异常：无法执行语句]的根本原因

组织。h2。jdbc。JdbcSQLIntegrityConstraintViolationException:唯一索引或主键冲突：“PUBLIC.STUDENT（STUDENT_ID）[0，NULL，NULL]上的主键”；SQL语句：将值（？、、、？）插入学生（班级id、学生姓名、学生id）[23505-200]

pplication.properties：

spring.h2.console.enabled=true
spring.h2.console.path=/h2-console
spring.datasource.url=jdbc:h2:mem:testdb
hibernate.check_nullability=false
spring.jpa.hibernate.ddl-auto=create

Student.class

@Entity(name = "STUDENT")
public class Student {

    @Id
    @Column(name = "Student_Id")
    private int studentID;

    @Column(name = "Student_Name")
    private String studentName;

    @ManyToOne(cascade = javax.persistence.CascadeType.ALL)
    @JoinColumn(name = "class_id", nullable = true)
    private Classs classs;

    public int getStudentID() {
        return studentID;
    }

    public void setStudentID(int studentID) {
        this.studentID = studentID;
    }

    public String getStudentName() {
        return studentName;
    }

    public void setStudentName(String studentName) {
        this.studentName = studentName;
    }

    
    public Classs getClasss() {
        return classs;
    }

    public void setClasss(Classs studentClass) {
        this.classs = studentClass;
    }

}

班级

@Entity(name = "CLASSS")
public class Classs {

    @Id
    @Column(name = "Classs_Id")
    private int classsId;
    
    @Column(name = "Classs_Name")
    private String classsName;
    
    @OneToMany(fetch = FetchType.LAZY)
    private List<Student> students;

    public int getClasssId() {
        return classsId;
    }

    public void setClasssId(int classsId) {
        this.classsId = classsId;
    }

    public String getClasssName() {
        return classsName;
    }

    public void setClasssName(String classsName) {
        this.classsName = classsName;
    }

}

学生服务。班

@Service
public class StudentService {

    @Autowired
    private StudentRepostry studentRepository;

    public List<Student> getAllStudents() {
        return studentRepository.findAll();
    }

    public Optional<Student> findById(Integer id) {
        return studentRepository.findById(id);
    }
    
    public Student insertStudent(Student student) {
        return studentRepository.save(student);
    }

    public Student updatingStudent(Student student) {
        return studentRepository.save(student);
    }

    public void deleteStudentById(int id) {
        studentRepository.deleteById(id);
        
    }
}

classs服务。班

@Service
public class ClasssService {
    
    @Autowired
    private ClasssRepository classsRepository;

    public Classs insertClass(Classs classs) {
        return classsRepository.save(classs);
    }
}

大学管理者。班

@RestController
@RequestMapping("/university")
public class UniversityRegController {

    @Autowired
    private StudentService studentService;
    
    @Autowired
    private ClasssService classsService;

    @GetMapping("/students")
    public List<Student> getAllStudentsList() {
        return studentService.getAllStudents();
    }
    
    @GetMapping("/student/{id}")
    public Optional<Student> getStudentById(@PathVariable int id) {
        return studentService.findById(id);
    }

    @PostMapping("/registerStudent")
    public Student registerStudent(@RequestBody Student student) {
        return studentService.insertStudent(student);
    }
    
    @PostMapping("/registerClass")
    public Classs registerClass(@RequestBody Classs classs) {
        return classsService.insertClass(classs);
    }
    
    @PutMapping("/updateStudent")
    public Student updateStudent(@RequestBody Student student) {
        return studentService.updatingStudent(student);
    }
    
    @DeleteMapping("/deleteStudent/{id}")
    public void deleteStudentById(@PathVariable int id) {
        studentService.deleteStudentById(id);
    }
}

URI：http://localhost:8080/university/registerStudentREST POST方法：

{
    "Student": 
            {     "Classs":
                            {
                                "classsId":108,
                                "classsName":"8th Class"
                            },
                "studentID": 11,
                "studentName": "Jasdfngid"
            }
}

Answer 1

您试图创建两行，其中的STUDENT_ID是主键（这意味着两行上的STUDENT_ID不能相同，也不能为NULL）