ACC2000: Checking Who Logged into Database with Jet UserRoster

• Microsoft Access 2000

SUMMARY

By using Microsoft Visual Basic for Applications in Microsoft Access 2000, you can output a list of users who are logged into a database. The code example in this article show you how to do this.

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MORE INFORMATION

The user list feature provides a way of determining who is currently connected to a Microsoft Jet database. The list can be obtained via the ADO programming interface and returns the following information for each user:

• Name of the computer that the user is using.



• Security name, that is, the user ID.



• Whether or not the user is currently connected to the database. (A user's ID remains in the lock database until the last user disconnects or until the slot is reclaimed for a new user connection.)



• Whether or not the user connection was terminated normally.



• The user list capability can be used in conjunction with the connection control capability to determine which users are still connected, so that they can be asked to disconnect.

1. Copy the Northwind sample database the C:\ folder.



2. In Microsoft Access, open C:\Northwind.



3. In the Database Window, click Modules under Objects, and then click New.



4. Save the module as ShowUsers.



5. Type the following code in the new ShowUsers module:




Sub ShowUserRosterMultipleUsers()
    Dim cn As New Connection
    Dim cn2 As New Connection
    Dim rs As New Recordset
    Dim i, j As Long

    cn.Provider = "Microsoft.Jet.OLEDB.4.0"
    cn.Open "Data Source=c:\Northwind.mdb"

    cn2.Open "Provider=Microsoft.Jet.OLEDB.4.0;" _
    & "Data Source=c:\Northwind.mdb"

    ' The user roster is exposed as a provider-specific schema rowset
    ' in the Jet 4 OLE DB provider.  You have to use a GUID to
    ' reference the schema, as provider-specific schemas are not
    ' listed in ADO's type library for schema rowsets

    Set rs = cn.OpenSchema(adSchemaProviderSpecific, _
    , "{947bb102-5d43-11d1-bdbf-00c04fb92675}")

    'Output the list of all users in the current database.

    Debug.Print rs.Fields(0).Name, "", rs.Fields(1).Name, _
    "", rs.Fields(2).Name, rs.Fields(3).Name

    While Not rs.EOF
        Debug.Print rs.Fields(0), rs.Fields(1), _
        rs.Fields(2), rs.Fields(3)
        rs.MoveNext
    Wend

End Sub 

6. Close the Northwind database and when prompted, save changes to ShutDownDB (This must be done to release an exclusive lock on the database due to the code you have just added).



7. Re-open C:\Northwind.



8. Press CTRL+G to open the Immediate Window in the Visual Basic Editor.



9. Type the following in the Immediate window and press ENTER:




ShowUserRosterMultipleUsers 

Note that in the Immediate window returns a list of users in the database.

Additional query words: inf

Keywords          : kbdta 
Version           : WINDOWS:2000
Platform          : WINDOWS 
Issue type        : kbhowto 

Last Reviewed: July 6, 1999