C# ASP.NET核心Web API-POST方法引发重复（自动递增）PK异常

我在这样的代码中遇到了奇怪的行为：

// POST: /tutors 
        [HttpPost]
        public async Task<IActionResult> CreateTutor([FromBody] TutorViewModel vmTutor) {

            if (vmTutor == null)
                return new StatusCodeResult(500); // Internal Server Error 

            try
            {
                // check if the Person with given personId exists 
                Person person = await _unitOfWork.People.GetAsync(vmTutor.PersonId);
                if (person == null) throw new Exception("Given Person doesn't exists.");

                // create new Tutor entity for given Person entity 
                var newTutor = new Tutor
                {
                    Description = vmTutor.Description,
                    Qualifications = vmTutor.Qualifications,
                    IsSuperTutor = vmTutor.IsSuperTutor,
                    //PersonId = vmTutor.PersonId
                    Person = person
                };

                // Add new Tutor to DBContext and save changes 
                await _unitOfWork.Tutors.AddAsync(newTutor);
                _unitOfWork.Complete();

                vmTutor.TutorId = newTutor.TutorId;

                return CreatedAtAction(nameof(GetTutor), new { tutorId = vmTutor.TutorId }, vmTutor);

            } catch(Exception e) {
                return new ObjectResult(new { error = e.Message }); 
            }
        }

正如我所记得的，当存在其非异步版本时，相同的代码可以正常工作，即如下所示：

Microsoft.EntityFrameworkCore.DbUpdateException: An error occurred while updating the entries. See the inner exception for details. ---> System.Data.SqlClient.SqlException: Cannot insert duplicate key row in object 'dbo.Tutors' with unique index 'IX_Tutors_PersonId'. The duplicate key value is (6).
      The statement has been terminated.

// POST: /tutors 
        [HttpPost]
        public IActionResult CreateTutor([FromBody] TutorViewModel vmTutor) {

            if (vmTutor == null)
                return new StatusCodeResult(500); // Internal Server Error 

            try
            {
                // check if the Person with given personId exists 
                Person person =  _unitOfWork.People.Get(vmTutor.PersonId);
                if (person == null) throw new Exception("Given Person doesn't exists.");

                // create new Tutor entity for given Person entity 
                var newTutor = new Tutor
                {
                    Description = vmTutor.Description,
                    Qualifications = vmTutor.Qualifications,
                    IsSuperTutor = vmTutor.IsSuperTutor,
                    PersonId = vmTutor.PersonId
                    //Person = person
                };

                // Add new Tutor to DBContext and save changes 
                _unitOfWork.Tutors.AddAsync(newTutor);
                _unitOfWork.Complete();

                vmTutor.TutorId = newTutor.TutorId;

                return CreatedAtAction(nameof(GetTutor), new { tutorId = vmTutor.TutorId }, vmTutor);

            } catch(Exception e) {
                return new ObjectResult(new { error = e.Message }); 
            }
        }

您能解释一下为什么我在使用异步版本时不能直接在Tutor实体中分配外键PersonId吗？并向我解释什么时候应该首选此异步版本而不是临时的实体CRUD操作

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谢谢你的帮助和解释

例外情况没有提到与您的PK冲突。它在似乎是唯一索引的IX_Tutors_PersonId上抛出错误。通常PK或FK是唯一的？但数据库中并没有像PersonId这样具有键值的记录。使用具有相同id的Person对象关联时的插入可以正常工作。我还记得，当没有这个异步/等待修饰符和使用_unitOfWork.People.GetAsync（）方法显式检查数据库中的人员存在时，这个方法可以很好地工作