Read and write File ODBC data sources

A file DSN is nothing but a text file that contains all the parameters for an ODBC connection. To prove this, just go to the default directory that holds all File DSNs (this is the \Program Files\Common Files\ODBC\Data Sources directory on Windows's boot drive) and load any .dsn file into a text editor such as Notepad. For example, this is the typical contents of such a file:


[ODBC]
DRIVER=SQL Server
UID=sa
DATABASE=pubs
WSID=P2
APP=Visual Basic
SERVER=(local)
Description=Pubs in local SQL Server

That said, it's pretty easy to manually write a Visual Basic procedure that creates a File DSN. For example, the following routine creates a connection to any database on the local SQL Server, using the provided username and password:


' create a File DSN that points to a SQL Server database
'
' if ServerName is omitted, it connects to the local SQL Server

Sub CreateSQLServerDSN(ByVal DSNFile As String, ByVal DatabaseName As String, _
    ByVal UserName As String, ByVal Password As String, _
    Optional ByVal ServerName As String, Optional ByVal Description As String)
    Dim fnum As Integer
    Dim isOpen As Boolean
    
    On Error GoTo ErrorHandler
    
    fnum = FreeFile
    Open DSNFile For Output As #fnum
    isOpen = True
    
    Print #fnum, "[ODBC]"
    Print #fnum, "DRIVER=SQL Server"
    Print #fnum, "UID=" & UserName
    Print #fnum, "DATABASE=" & DatabaseName
    Print #fnum, "SERVER=" & IIf(ServerName = "", "(local)", ServerName)
    If Not IsMissing(Description) Then
        Print #fnum, "DESCRIPTION=" & Description
    End If
    
    Close #fnum
    Exit Sub
    
ErrorHandler:
    If isOpen Then Close #fnum
    Err.Raise Err.Number, , Err.Description

End Sub

Francesco Balena

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