Private Sub Login_Click()
 
    Dim conn As New ADODB.Connection
    Dim rs As New ADODB.Recordset
 
    Dim user As String
    Dim password As String
 
    user = txt_username.Text    'pull data from txt box
    password = txt_password.Text    'pull data from txt box
 
    conn.Open "your_database_connection_string"
    rs.Open "select * from your_login_table"
 
    'make sure rs is not empty
    If rs.BOF = False Then
        While rs.EOF = False
            If user = rs.Fields("Column_Name_For_Username") And _
                password = rs.Fields("Column_Name_For_Password") Then
                MsgBox "Validation successful"
                Exit Sub
            End If
            rs.MoveNext
        Wend
 
        MsgBox "No such user exists"
    Else
        MsgBox "The recordset is empty", vbCritical
    End If
 
End Sub