我无法使用Entity Framework Core更新/编辑一对一关系

Question

All CRUD operations are working except updating/editing. I am using Pomelo since I am using Mysql. For the issue am facing, am using the same create form to edit the data but it throws an exception when I try editing.

This is the exception:

fail: Microsoft.EntityFrameworkCore.Update[10000]
An exception occurred in the database while saving changes for context type 'ICFERApp.Data.ApplicationDbContext'.

Microsoft.EntityFrameworkCore.DbUpdateException: An error occurred while updating the entries. See the inner exception for details.

MySql.Data.MySqlClient.MySqlException: Duplicate entry '3' for key 'IX_Education_StudentId'

MySql.Data.MySqlClient.MySqlException: Duplicate entry '3' for key 'IX_Education_StudentId'

at MySqlConnector.Core.ResultSet.ReadResultSetHeaderAsync(IOBehavior ioBehavior) in C:\\projects\\mysqlconnector\\src\\MySqlConnector\\Core\\ResultSet.cs:line 43
--- End of inner exception stack trace ---
at MySql.Data.MySqlClient.MySqlDataReader.ActivateResultSet(ResultSet resultSet) in C:\\projects\\mysqlconnector\\src\\MySqlConnector\\MySql.Data.MySqlClient\\MySqlDataReader.cs:line 81
at MySql.Data.MySqlClient.MySqlDataReader.ReadFirstResultSetAsync(IOBehavior ioBehavior) in C:\\projects\\mysqlconnector\\src\\MySqlConnector\\MySql.Data.MySqlClient\\MySqlDataReader.cs:line 307

These are my model classes:

public class Student
{
        [Key]
        public long Id { get; set; }
        [Display(Name="First Name")]
        public string FirstName { get; set; }
        [Display(Name="Middle Name")]
        public string MiddleName { get; set; }
        [Display(Name="Last Name")]
        public string LastName { get; set; }
        [Display(Name="Nationality")]
        public string Nationality { get; set; }
        [Display(Name="Gender")]
        public string Gender { get; set; }
        [Display(Name="Religion")]
        public string Religion { get; set; }
        [Display(Name="Medical Condition")]
        public string MedicalCondition { get; set; }
        [Display(Name="Deceased")]
        public string Deceased { get; set; }
        [Display(Name="Home Address")]
        public string HomeAddress { get; set; }
        [Display(Name="Country Of Residence")]
        public string CountryOfResidence { get; set; }
        [Display(Name="City")]
        public string City { get; set; }
        [Display(Name="Date Of Birth")]
        public DateTime DateOfBirth { get; set; }
        public int Age { get; set; }

        public virtual Parents Parents { get; set; }
        public virtual Education Education { get; set; }
}

public class Parents
{
        public long Id { get; set; }
        [Display(Name="Religion Of Deceased Father")]
        public string ReligionOfDeceasedFather { get; set; }
        [Display(Name="Religion Of Deceased Mother")]
        public string ReligionOfDeceasedMother { get; set; }
        [Display(Name="Date Of Demise Father")]
        [DisplayFormat(DataFormatString = "{0:dd.MM.yyyy}")]
        public DateTime DateOfDemiseOfFather { get; set; }
        [Display(Name="Date Of Demise Mother")]
        [DisplayFormat(DataFormatString = "{0:dd.MM.yyyy}")]
        public DateTime DateOfDemiseOfMother { get; set; }
        [Display(Name="Names of Mother")]
        public string NamesOfMother { get; set; }
        [Display(Name="Names of Father")]
        public string NamesOfFather { get; set; }
        [Display(Name="Religion of Mother")]
        public string ReligionOfMother { get; set; }
        [Display(Name="Marital Status of Mother")]
        public string MaritalStatusOfMother { get; set; }
        [Display(Name="Occupation of Mother")]
        public string OccupationOfMother { get; set; }
        [Display(Name="Monthly Income")]
        public double MonthlyIncome { get; set; }
        public virtual Student Student { get; set; }

        public long? StudentId { get; set; }
}

public class Education
{
    public long Id { get; set; }
    [Display(Name="Education Level")]
    public string EducationLevel { get; set; }
    [Display(Name="School")]
    public string School { get; set; }
    [Display(Name="Address of School")]
    public string AddressOfSchool { get; set; }
    [Display(Name="Head Teacher")]
    public string HeadTeacher { get; set; }
    [Display(Name="Telephone")]
    public string Telephone { get; set; }
    public  virtual Student Student { get; set; }

    public long? StudentId { get; set; }
}

My question would be why can't I be able to update automatically with the Entity Framework Core?

These are the methods responsible for editing in my Controller class :

[HttpPost]
public IActionResult New(Student student, string IsEditMode)
{
     if (!ModelState.IsValid)
     {
         ViewBag.IsEditMode = IsEditMode;
         return View(student);
     }

     try
     {
         if (IsEditMode.Equals("false"))
         {
              _studentRepository.Create(student);
         }
         else
         {
             _studentRepository.Edit(student);
         }

         return RedirectToAction(nameof(Index));
     }
     catch (Exception e)
     {
         return RedirectToAction(nameof(Index));
     }
}

public IActionResult Edit(int id)
{
    try
    {
        ViewBag.IsEditMode = "true";

        var student = _studentRepository.GetSingleStudent(id);

        return View("New", student);
    }
    catch (Exception ex)
    {
        return Content("Could not find Pet");
    }
}

Then, in my Repository class, this is the Edit method:

public void Edit(Student student)
{
    _context.Students.Update(student);
    _context.SaveChanges();
} 

I will be very grateful with help regarding this blocker. Thanks.

EDIT

This is my form which handles both Creating and Editing.

@model Student

<form asp-action="New" method="Post" asp-controller="Student">
    <div asp-validation-summary="All"></div>

    <input asp-for="Id" type="hidden"/>
    <input name="IsEditMode" id="IsEditMode" value="@ViewBag.IsEditMode" type="hidden"/>

    <div class="form-row">
        <div class="col">
            <label asp-for="FirstName"></label>
            <input asp-for="FirstName" class="form-control"/>
            <span asp-validation-for="FirstName" class="text-danger"></span>
        </div>
        <div class="col">
            <label asp-for="MiddleName"></label>
            <input asp-for="MiddleName" class="form-control"/>
            <span asp-validation-for="MiddleName" class="text-danger"></span>
        </div>
    </div>
    <div class="form-row">
        <div class="col">
            <label asp-for="LastName"></label>
            <input asp-for="LastName" class="form-control"/>
            <span asp-validation-for="LastName" class="text-danger"></span>
        </div>
        <div class="col">
            <label asp-for="Nationality"></label>
            <input asp-for="Nationality" class="form-control"/>
            <span asp-validation-for="Nationality" class="text-danger"></span>
        </div>
    </div>
    <div class="form-row">
        <div class="col">
            <label asp-for="Gender"></label>
            <input asp-for="Gender" class="form-control"/>
            <span asp-validation-for="Gender" class="text-danger"></span>
        </div>
        <div class="col">
            <label asp-for="Religion"></label>
            <input asp-for="Religion" class="form-control"/>
            <span asp-validation-for="Religion" class="text-danger"></span>
        </div>
    </div>

<div class="form-row">
    <div class="col">
        <label asp-for="MedicalCondition"></label>
        <input asp-for="MedicalCondition" class="form-control"/>
        <span asp-validation-for="MedicalCondition" class="text-danger"></span>
    </div>
    <div class="col">
        <label asp-for="Deceased"></label>
        <input asp-for="Deceased" class="form-control"/>
        <span asp-validation-for="Deceased" class="text-danger"></span>
    </div>
</div>

    <div class="form-row">
        <div class="col">
            <label asp-for="HomeAddress"></label>
            <input asp-for="HomeAddress" class="form-control"/>
            <span asp-validation-for="HomeAddress" class="text-danger"></span>
        </div>
        <div class="col">
            <label asp-for="CountryOfResidence"></label>
            <input asp-for="CountryOfResidence" class="form-control"/>
            <span asp-validation-for="CountryOfResidence" class="text-danger"></span>
        </div>
    </div>
<div class="form-row">
    <div class="col">
        <label asp-for="City"></label>
        <input asp-for="City" class="form-control"/>
        <span asp-validation-for="City" class="text-danger"></span>
    </div>
    <div class="col">
        <label asp-for="DateOfBirth"></label>
        <input asp-for="DateOfBirth" class="form-control"/>
        <span asp-validation-for="DateOfBirth" class="text-danger"></span>
    </div>
</div>
<div class="form-row">
    <div class="col">
        <label asp-for="Parents.ReligionOfDeceasedFather"></label>
        <input asp-for="Parents.ReligionOfDeceasedFather" class="form-control"/>
        <span asp-validation-for="Parents.ReligionOfDeceasedFather" class="text-danger"></span>
    </div>
    <div class="col">
        <label asp-for="Parents.ReligionOfDeceasedMother"></label>
        <input asp-for="Parents.ReligionOfDeceasedMother" class="form-control"/>
        <span asp-validation-for="Parents.ReligionOfDeceasedMother" class="text-danger"></span>
    </div>
</div>
    <div class="form-row">
        <div class="col">
            <label asp-for="Parents.DateOfDemiseOfFather"></label>
            <input asp-for="Parents.DateOfDemiseOfFather" class="form-control"/>
            <span asp-validation-for="Parents.DateOfDemiseOfFather" class="text-danger"></span>
        </div>
        <div class="col">
            <label asp-for="Parents.DateOfDemiseOfMother"></label>
            <input asp-for="Parents.DateOfDemiseOfMother" class="form-control"/>
            <span asp-validation-for="Parents.DateOfDemiseOfMother" class="text-danger"></span>
        </div>
    </div>
    <div class="form-row">
        <div class="col">
            <label asp-for="Parents.NamesOfMother"></label>
            <input asp-for="Parents.NamesOfMother" class="form-control"/>
            <span asp-validation-for="Parents.NamesOfMother" class="text-danger"></span>
        </div>
        <div class="col">
            <label asp-for="Parents.NamesOfFather"></label>
            <input asp-for="Parents.NamesOfFather" class="form-control"/>
            <span asp-validation-for="Parents.NamesOfFather" class="text-danger"></span>
        </div>
    </div>
    <div class="form-row">
        <div class="col">
            <label asp-for="Parents.ReligionOfMother"></label>
            <input asp-for="Parents.ReligionOfMother" class="form-control"/>
            <span asp-validation-for="Parents.ReligionOfMother" class="text-danger"></span>
        </div>
        <div class="col">
            <label asp-for="Parents.MaritalStatusOfMother"></label>
            <input asp-for="Parents.MaritalStatusOfMother" class="form-control"/>
            <span asp-validation-for="Parents.MaritalStatusOfMother" class="text-danger"></span>
        </div>
    </div>
    <div class="form-row">
        <div class="col">
            <label asp-for="Parents.OccupationOfMother"></label>
            <input asp-for="Parents.OccupationOfMother" class="form-control"/>
            <span asp-validation-for="Parents.OccupationOfMother" class="text-danger"></span>
        </div>
        <div class="col">
            <label asp-for="Parents.MonthlyIncome"></label>
            <input asp-for="Parents.MonthlyIncome" class="form-control"/>
            <span asp-validation-for="Parents.MonthlyIncome" class="text-danger"></span>
        </div>
    </div>
<div class="form-row">
    <div class="col">
        <label asp-for="Guardian.FirstName"></label>
        <input asp-for="Guardian.FirstName" class="form-control"/>
        <span asp-validation-for="Guardian.FirstName" class="text-danger"></span>
    </div>
    <div class="col">
        <label asp-for="Guardian.MiddleName"></label>
        <input asp-for="Guardian.MiddleName" class="form-control"/>
        <span asp-validation-for="Guardian.MiddleName" class="text-danger"></span>
    </div>
</div>
<div class="form-row">
    <div class="col">
        <label asp-for="Guardian.LastName"></label>
        <input asp-for="Guardian.LastName" class="form-control"/>
        <span asp-validation-for="LastName" class="text-danger"></span>
    </div>
    <div class="col">
        <label asp-for="Guardian.RelationshipToOrphan"></label>
        <input asp-for="Guardian.RelationshipToOrphan" class="form-control"/>
        <span asp-validation-for="Guardian.RelationshipToOrphan" class="text-danger"></span>
    </div>
</div>
<div class="form-row">
    <div class="col">
        <label asp-for="Guardian.Occupation"></label>
        <input asp-for="Guardian.Occupation" class="form-control"/>
        <span asp-validation-for="Guardian.Occupation" class="text-danger"></span>
    </div>
    <div class="col">
        <label asp-for="Guardian.MonthlyIncome"></label>
        <input asp-for="Guardian.MonthlyIncome" class="form-control"/>
        <span asp-validation-for="Guardian.MonthlyIncome" class="text-danger"></span>
    </div>
</div>
<div class="form-row">
    <div class="col">
        <label asp-for="Guardian.EmployersName"></label>
        <input asp-for="Guardian.EmployersName" class="form-control"/>
        <span asp-validation-for="Guardian.EmployersName" class="text-danger"></span>
    </div>
    <div class="col">
        <label asp-for="Guardian.WorkAddress"></label>
        <input asp-for="Guardian.WorkAddress" class="form-control"/>
        <span asp-validation-for="Guardian.WorkAddress" class="text-danger"></span>
    </div>
</div>
<div class="form-row">
    <div class="col">
        <label asp-for="Guardian.MobileNo"></label>
        <input asp-for="Guardian.MobileNo" class="form-control"/>
        <span asp-validation-for="Guardian.MobileNo" class="text-danger"></span>
    </div>
    <div class="col">
        <label asp-for="Guardian.PhysicalLocation"></label>
        <input asp-for="Guardian.PhysicalLocation" class="form-control"/>
        <span asp-validation-for="Guardian.PhysicalLocation" class="text-danger"></span>
    </div>
</div>
    <div class="form-row">
        <div class="col">
            <label asp-for="Guardian.Comments"></label>
            <input asp-for="Guardian.Comments" class="form-control"/>
            <span asp-validation-for="Guardian.Comments" class="text-danger"></span>
        </div>
        <div class="col">
            <label asp-for="Education.EducationLevel"></label>
            <input asp-for="Education.EducationLevel" class="form-control"/>
            <span asp-validation-for="Education.EducationLevel" class="text-danger"></span>
        </div>
    </div>
<div class="form-row">
    <div class="col">
        <label asp-for="Education.School"></label>
        <input asp-for="Education.School" class="form-control"/>
        <span asp-validation-for="Education.School" class="text-danger"></span>
    </div>
    <div class="col">
        <label asp-for="Education.AddressOfSchool"></label>
        <input asp-for="Education.AddressOfSchool" class="form-control"/>
        <span asp-validation-for="Education.AddressOfSchool" class="text-danger"></span>
    </div>
</div>
<div class="form-row">
    <div class="col">
        <label asp-for="Education.HeadTeacher"></label>
        <input asp-for="Education.HeadTeacher" class="form-control"/>
        <span asp-validation-for="Education.HeadTeacher" class="text-danger"></span>
    </div>
    <div class="col">
        <label asp-for="Education.Telephone"></label>
        <input asp-for="Education.Telephone" class="form-control"/>
        <span asp-validation-for="Education.Telephone" class="text-danger"></span>
    </div>
</div>
    <div class="form-row">
        <div class="col">
            <label asp-for="Siblings.NumberOfBrothers"></label>
            <input asp-for="Siblings.NumberOfBrothers" class="form-control"/>
            <span asp-validation-for="Siblings.NumberOfBrothers" class="text-danger"></span>
        </div>
        <div class="col">
            <label asp-for="Siblings.NumberOfSisters"></label>
            <input asp-for="Siblings.NumberOfSisters" class="form-control"/>
            <span asp-validation-for="Siblings.NumberOfSisters" class="text-danger"></span>
        </div>
    </div>

<div class="form-group">
    <input asp-for="FirstName" type="submit" value="Save Student" class="btn btn-primary"/>
</div>

</form>

Answer 1

This is how you can update all the tables

public void Edit(Student student)
{
    var existingStudent = _context.Students.FirstOrDefault(s => s.Id == student.Id);
    if (existingStudent != null)
    {
        //do the update to the database             
        _context.Entry(existingStudent).CurrentValues.SetValues(student);
        _context.Entry(existingStudent).State = System.Data.Entity.EntityState.Modified;

        //then update the parent this way
        //first get the particular parent for this student
        var parent = _context.Parents.FirstOrDefault(m => m.StudentId == existingStudent.Id);

        _context.Entry(parent).CurrentValues.SetValues(student.Parents);
        _context.Entry(parent).State = System.Data.Entity.EntityState.Modified;

        //do the same for Educations
    }
    _context.SaveChanges();
}