Hi,
I am trying to get to grips with the “NULL” dates in SQL database.

Q1) The PrepareDateForDb code works OK on an update of a record, but when I try add a record with a null date it throws an exception?

Q2) The date time when I retrieve the datetime stored in the database as ToOADate format, the date time is a day out. I assume as I use a UK date time it is placing my date two hours behind. My customers may not have the same datetime location.

Thanks

This works OK
Code:
strSQL = "UPDATE [Business] SET" & _
...
" ,DateVerified = " & PrepareDateForDb(mtbDateVerified.Text) & _
...
This throws an exception
Code:
...
With cmSQL
...
.Parameters.Add(New SqlParameter("@DateVerified", SqlDbType.DateTime)).Value = PrepareDateForDb(mtbDateVerified.Text)
Code:
‘ Prepare date for inserting into database
    Function PrepareDateForDb(ByVal strValue As String) As String
        'Empty MaskedTextBox field gives “  /  /”
        If strValue.StartsWith(" ") Then
            Return "NULL"
            Exit Function
        End If
        'Empty date field
        If strValue.Trim() = "" Then
            Return "NULL"
        Else
            'Convert date to ToOADate 
            Dim strDt As String = CDate(strValue).ToOADate
            Return strDt
        End If
    End Function