Hi, How do i prevent user to insert duplicate record in my database? I need to check whether there is any staffNo same in the database, how do i go abt the codes? Can u pls help mi, n give mi some sample codes?
Below are my codes for e inserting of new record.

Private Sub addStaff()
' Validate form values.
If Not IsValidForm() Then
Exit Sub
End If

Dim cnSQL As SqlConnection
Dim cmSQL As SqlCommand
Dim strSQL As String

Try
strSQL = "INSERT INTO StaffInfo(SurName, Name, StaffNo, Designation, Department, ExtNo, Email) VALUES ('" + txtSur.Text + " ','" + txtName.Text + "','" + txtStaffNo.Text + "','" + txtDes.Text + "','" + txtDep.Text + "','" + txtExt.Text + "', '" + txtEmail.Text + "')"
cnSQL = New SqlConnection(ConnectionString)
cnSQL.Open()
cmSQL = New SqlCommand(strSQL, cnSQL)

'Execute query
cmSQL.ExecuteNonQuery()

' Close and Clean up objects
cnSQL.Close()
cmSQL.Dispose()
cnSQL.Dispose()

Catch Exp As SqlException
MsgBox(Exp.Message, MsgBoxStyle.Critical, "SQL Error")

Catch Exp As Exception
MsgBox(Exp.Message, MsgBoxStyle.Critical, "General Error")
End Try

MessageBox.Show(Me, "Your record is saved!", "Record Saved", MessageBoxButtons.OK, MessageBoxIcon.Asterisk)
Me.Close()
End Sub