检查员工身份证号码的唯一性

Question

似乎无法弄清楚如何检查唯一的员工 ID 号。我知道验证必须在表单加载中进行，只是不知道如何去做。

Public Class Form1
  Dim filename As String
  Dim dataFile As System.IO.File
  Dim dataWrite As System.IO.StreamWriter

  ''LOADING AND WRITE TO TEXT DOCUMENT
  Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    'asks user for file name 
    filename = InputBox("Enter output file name")
    If IO.File.Exists(filename) Then
      dataWrite = IO.File.AppendText(filename)
    Else
      MessageBox.Show("filename does not exist")
      filename = InputBox("Enter output file name")
      dataWrite = IO.File.CreateText(filename)
    End If
    cboDepart.Items.Add("Accounting")
    cboDepart.Items.Add("Administration")
    cboDepart.Items.Add("Marketing")
    cboDepart.Items.Add("MIS")
    cboDepart.Items.Add("Sales")
  End Sub
  '------

  Public EMPLOYEEIDS As String
  Dim employeeID1 As ServerData()
  Dim employeeID2 As ServerData()
  Dim reader As String = My.Computer.FileSystem.ReadAllText("servers.lst")
  Dim s() As String
  Dim Totalemployeeids As String = CStr(reader.Length)
  Dim x As Integer = 0
  Dim myArray As String() = reader.Split("|"c)
  For x = 1 To Totalemployeeids
    employeeID1(x).ServerName = myArray(0)
    employeeID2(x).IDname = myarray(0)

    Form1_load.ListBox1.Items.Add(Servers(x).ServerName)
    x += 1
  Next

  Structure ServerData
  End Structure
End Class

Answer 1

您通常不要从客户端插入唯一 ID。相反，它由数据库服务器自动插入。有一种方法可以取回插入的 ID，如果您需要它进行显示（也可以作为成功插入记录的确认）：

SELECT SCOPE_IDENTITY()

此答案中显示了一个示例：

• How to get last inserted id? (C#)

在客户端，您需要实现除 ID 之外的所有内容的插入，在这种情况下，您不需要检查唯一性。不过，提交时可能会出现其他验证问题（唯一密钥违规、数据类型不匹配） - 确保您捕获异常并将它们适当地显示给用户。