无法启用约束。一行或多行包含违反非空，唯一或外键约束的值

Question

我的错误很简单，但对我来说很难修复它，因为我的知识不好。这是当我通过单击AddStudent记录添加按钮输入记录，然后记录，我删除记录StudentID = 1，名字= Raju，姓氏= Abbasi

后删除它，然后按保存更改甚至之后，当我再次尝试使用ID = 1只表示与ID = 1进入记录，我已被删除并记录StudentID = 1，名字=拉姆，姓氏=俏皮。然后误差发生的是

 

    private static SqlDataAdapter CreateSutdentDataAdapter() 
      { 

       string gettSQL = "SELECT * FROM Student"; 

       string insertSQL = "SET IDENTITY_INSERT Student ON;INSERT INTO Student(StudentID, FirstName,LastName,Gender,GPA,MyImage)" + 
        "VALUES (@StudentID,@FirstName,@LastName,@Gender,@GPA,@MyImage);SET IDENTITY_INSERT Student OFF"; 
       string updateSQL = "UPDATE Student SET [email protected],[email protected] ,[email protected], [email protected]," + 
       " [email protected] WHERE [email protected]"; 
       string deleteSQL = "DELETE FROM Student WHERE [email protected]"; 

       SqlDataAdapter dataAdapter = new SqlDataAdapter(); 

       dataAdapter.SelectCommand = new SqlCommand(gettSQL, ConnectionManager.GetConnection()); 

       dataAdapter.InsertCommand = new SqlCommand(insertSQL, ConnectionManager.GetConnection()); 

       dataAdapter.InsertCommand.Parameters.Add("@StudentID", SqlDbType.Int).SourceColumn = "StudentID"; 
       dataAdapter.InsertCommand.Parameters.Add("@FirstName", SqlDbType.VarChar,25).SourceColumn = "FirstName"; 
       dataAdapter.InsertCommand.Parameters.Add("@LastName", SqlDbType.VarChar, 25).SourceColumn = "LastName"; 
       dataAdapter.InsertCommand.Parameters.Add("@Gender", SqlDbType.VarChar ,1).SourceColumn = "Gender"; 
       dataAdapter.InsertCommand.Parameters.Add("@GPA", SqlDbType.Float).SourceColumn = "GPA"; 
       dataAdapter.InsertCommand.Parameters.Add("@MyImage", SqlDbType.VarBinary).SourceColumn = "MyImage"; 

       dataAdapter.UpdateCommand = new SqlCommand(updateSQL, ConnectionManager.GetConnection()); 
       dataAdapter.UpdateCommand.Parameters.Add("@StudentID", SqlDbType.Int).SourceColumn = "StudentID"; 
       dataAdapter.UpdateCommand.Parameters.Add("@FirstName", SqlDbType.VarChar,25).SourceColumn = "FirstName"; 
       dataAdapter.UpdateCommand.Parameters.Add("@LastName", SqlDbType.VarChar, 25).SourceColumn = "LastName"; 
       dataAdapter.UpdateCommand.Parameters.Add("@Gender", SqlDbType.VarChar ,1).SourceColumn = "Gender"; 
       dataAdapter.UpdateCommand.Parameters.Add("@GPA", SqlDbType.Float).SourceColumn = "GPA"; 
       dataAdapter.UpdateCommand.Parameters.Add("@MyImage", SqlDbType.VarBinary).SourceColumn = "MyImage"; 
       dataAdapter.DeleteCommand = new SqlCommand(deleteSQL, ConnectionManager.GetConnection()); 
       dataAdapter.DeleteCommand.Parameters.Add("@StudentID", SqlDbType.Int).SourceColumn = "StudentID"; 

       return dataAdapter; 

      } 

     private static void DefinestudentTableSchema(DataTable table) 
     { 
      DataColumn StudentIDColumn = table.Columns.Add("StudentID", typeof(string)); 
      StudentIDColumn.AllowDBNull = false; 

      table.PrimaryKey = new DataColumn[] { StudentIDColumn }; 

      DataColumn StudentFirstName = table.Columns.Add("FirstName", typeof(string)); 
      StudentFirstName.MaxLength = 150; 
      DataColumn StudentLastName = table.Columns.Add("LastName", typeof(string)); 
      StudentLastName.MaxLength = 150; 
      DataColumn StudentGender = table.Columns.Add("Gender", typeof(string)); 

      DataColumn StudentGPA = table.Columns.Add("GPA", typeof(string)); 
      DataColumn StudentImage = table.Columns.Add("MyImage", typeof(Byte[])); 

     } 
     private static DataSet CreateStudentTrackerDataSet() 
     { 
      DataSet StudentTrackerDataSet = new DataSet(); 
      DataTable StudentTable = StudentTrackerDataSet.Tables.Add("Student"); 
      DefinestudentTableSchema(StudentTable); 
      return StudentTrackerDataSet; 
     } 

     public static DataSet GetData() 
     { 
      DataSet StudentTrakerDataSet = CreateStudentTrackerDataSet(); 
      StudentTrakerDataSet.EnforceConstraints = false; 
      StudentDataAdapter.Fill(StudentTrakerDataSet.Tables["Student"]); 

      StudentTrakerDataSet.EnforceConstraints = true; 
      return StudentTrakerDataSet; 
     } 

     public AddModifyStudentRecords(DataSet ds, DataRow row) 
     { 
public static void SaveData(ref DataSet changesDataSet) 
     { 
      DataSet addedDataSet = changesDataSet.GetChanges(DataRowState.Added); 
      if (addedDataSet != null) 
      { 
       StudentDataAdapter.Update(addedDataSet.Tables["Student"]); 
       changesDataSet.Merge(addedDataSet); // Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints 
      } 
      DataSet modifiedDataSet = changesDataSet.GetChanges(DataRowState.Modified); 
      if (modifiedDataSet != null) 
      { 
       StudentDataAdapter.Update(modifiedDataSet.Tables["Student"]); 
       changesDataSet.Merge(modifiedDataSet); 
      } 
      DataSet deletedDataSet = changesDataSet.GetChanges(DataRowState.Deleted); 
      if (deletedDataSet != null) 
      { 
       StudentDataAdapter.Update(deletedDataSet.Tables["Student"]); 
      deletedDataSet.Merge(deletedDataSet); 
      } 

这里是我的Addmodifyform逻辑，用于添加StudentID

 
public partial class AddModifyStudentRecords : Form 
    { 

     DataSet StudentTrackerDataSet; 
     DataRow currentRow; 


     public AddModifyStudentRecords() 
     { 
      InitializeComponent(); 
     } 

     public AddModifyStudentRecords(DataSet ds) 
     { 
      InitializeComponent(); 
      StudentTrackerDataSet = ds; 
      currentRow = null; 
     } 
    public AddModifyStudentRecords(DataSet ds, DataRow row) 
    { 
    InitializeComponent(); 
    StudentTrackerDataSet = ds; 
    currentRow = row; 
    textBox1.Text =currentRow["StudentID"] .ToString(); 
    textBox2.Text = currentRow["FirstName"].ToString(); 
    textBox4.Text = currentRow["LastName"].ToString(); 
    textBox3.Text = currentRow["Gender"].ToString(); 
    textBox5.Text = currentRow["GPA"].ToString(); 
    txtBrowseFile.Text = currentRow["MyImage"].ToString(); 
    byte[] data = (byte[])currentRow ["MyImage"]; 
    MemoryStream ms = new MemoryStream(data); 
    pictureBox1.Image = Image.FromStream(ms); 
    string StudentID = textBox1.Text.ToString(); 
    string StudentFirstName = textBox2.Text.ToString(); 
    string StudentLastName = textBox4.Text.ToString(); 
    string Gender = textBox3.Text.ToString(); 
    string GPA = textBox5.Text.ToString(); 
    Image MyImage = pictureBox1.Image; 
    DataTable table = StudentTrackerDataSet.Tables["Student"]; 
    if (currentRow == null) { 
    currentRow = table.NewRow(); 
    currentRow["StudentID"] = textBox1.Text.ToString(); 
    table.Rows.Add(currentRow); 
    } 
    currentRow .BeginEdit(); 
    currentRow ["StudentID" ]=StudentID ; 
    currentRow["FirstName"] = StudentFirstName; 
    currentRow["LastName"] = StudentLastName; 
    currentRow["Gender"] = Gender; 
    currentRow["GPA"] = GPA; 
    currentRow["MyImage"] = convertToByte(txtBrowseFile.Text); 
    currentRow.EndEdit(); 
    Close(); 
    } 

公共部分类AditStudent：表格 { //创建类可变数据集以跟踪学生 私人DataSet StudentTrackerDataset;

 public AditStudent() 
     { 
      InitializeComponent(); 

      dataGridView1.DataError += DataGridView1_DataError; 
      StudentTrackerDataset = ProjectOfSchool.DataAccessLayer.DAC.GetData(); 

      DataTable StudentTable = StudentTrackerDataset.Tables["Student"]; 

      dataGridView1.DataSource = StudentTable; 
      //StudentTable.Columns["ID"].AutoIncrement = true; 
      for (int i = 0; i < dataGridView1.Columns.Count; i++) 
       if (dataGridView1.Columns[i] is DataGridViewImageColumn) 
       { 
        ((DataGridViewImageColumn)dataGridView1.Columns[i]).ImageLayout = DataGridViewImageCellLayout.Stretch; 
        break; 
       } 
     } 
     private void DataGridView1_DataError(object sender, DataGridViewDataErrorEventArgs e) 
     { 

      string message = string.Format("Error in {0} columan in row {1}:{2}", e.ColumnIndex, e.RowIndex, e.Exception.Message); 

      MessageBox.Show(message, "Data Error", MessageBoxButtons.OK, MessageBoxIcon.Exclamation); 
     } 
     private void button1_Click(object sender, EventArgs e) 
     { 
      AddModifyStudentRecords AddStudent = new AddModifyStudentRecords(StudentTrackerDataset); 
      AddStudent.ShowDialog(); 
     } 
     private void button2_Click(object sender, EventArgs e) 
     { 
      object id = dataGridView1.CurrentRow.Cells["StudentID"].Value; 
      DataRow StudentRow = StudentTrackerDataset.Tables["Student"].Rows.Find(id); 
      AddModifyStudentRecords modifyStudent = new AddModifyStudentRecords(StudentTrackerDataset, StudentRow); 
      modifyStudent.ShowDialog(); 
     } 
     private void button3_Click(object sender, EventArgs e) 
     { 
      DialogResult result = MessageBox.Show("Are you sure", "Delete Current Row", MessageBoxButtons.YesNo, MessageBoxIcon.Question); 
      if (result == DialogResult.Yes) 
      { 
       object id = dataGridView1.CurrentRow.Cells["StudentID"].Value; 
       DataRow currentRow = StudentTrackerDataset.Tables["Student"].Rows.Find(id); 
       currentRow.Delete(); 
      } 
     } 
     private void button4_Click(object sender, EventArgs e) 
     { 
      if (!StudentTrackerDataset.HasChanges()) 
      { 
       MessageBox.Show("There are no Change to Save ", "Save Changes", MessageBoxButtons.OK, MessageBoxIcon.Exclamation); 
      } 
      else 
      { 
       try 
       { 
        DataSet changesDateSet = StudentTrackerDataset.GetChanges(); 
        ProjectOfSchool.DataAccessLayer.DAC.SaveData(ref changesDateSet); 
        StudentTrackerDataset.Merge(DAC.GetData()); 
        MessageBox.Show("Data Save Successfully.", "Save Changes"); 
       } 
       catch (SqlException ex) 
       { 
        MessageBox.Show("Data Not Saved:" + ex.Message, "Save Changes", MessageBoxButtons.OK, MessageBoxIcon.Exclamation); 
       } 
      } 
     } 
     private void button5_Click(object sender, EventArgs e) 
     { 
      if (!StudentTrackerDataset.HasChanges()) 
      { 
       MessageBox.Show("There are no Changes to Save.", "Save Changes", MessageBoxButtons.OK, MessageBoxIcon.Exclamation); 
      } 
      else 
      { 
       DialogResult result = MessageBox .Show ("Are you Sure?","Reject Changes", MessageBoxButtons.YesNo, MessageBoxIcon.Question); 
       if (result == DialogResult.Yes) 
       { 
        StudentTrackerDataset.RejectChanges(); 
       } 
      } 
     } 

，当我终止该程序，并重新执行该程序然后我看到StudntID = 1也保存到ID = 1

数据库或当我删除StudentID = 1然后按保存更改后按保存更改时，我也终止程序并重新计算，然后当我输入StudentID = 1然后没有错误发生

而其他方式没有终止是删除记录StudentID1但当你添加t他学生记录，但不添加StudentID = 1但在此情况下添加StudentID，否则错误也不会发生。亲爱的谢里克我已经解决了我的其他错误，但我仍然有错误，这是在我的Tittle所以请回应我的这个错误，我重新编辑我的代码也请所有重播我谢谢

我有记录在我的数据库有哪些以下数据类型作为

StudentID = INT，

姓= VARCHAR，则

名字= VARCHAR，则

性别= VARCHAR，则

GPA =浮动，

MYIMAGE = Vabinary（MAX）

，或者可以是数据行无法删除记录或更新该记录。我不知道请告诉我，谢谢回复我，我正在等待您的回复。

Answer 1

错误消息似乎表明您正在击中主键约束。 我建议你先停止允许用户输入学生证字段。让它在任何你使用的数据库中作为自动递增键生成。在Access中，它被称为自动编号。

一旦你这样做了，重新测试并发布结果。