使用Jet UserRoster判断谁登陆了Access2002/2003数据库

原文:http://support.microsoft.com/kb/285822

How to determine who is logged on to a database by using Microsoft Jet UserRoster in Access 2002 or in access 2003

Article ID	:	285822
Last Review	:	August 30, 2004
Revision	:	1.0

This article was previously published under Q285822

For a Microsoft access 2000 version of this article, see 198755.

Advanced: Requires expert coding, interoperability, and multiuser skills.

This article applies only to a Microsoft access database (.mdb).

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SUMMARY

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Procedure

SUMMARY

This article shows you how to use Microsoft Visual Basic for Applications to output a list of users who are logged onto a database.

Microsoft provides programming examples for illustration only, without warranty either expressed or implied, including, but not limited to, the implied warranties of merchantability or fitness for a particular purpose. This article assumes that you are familiar with the programming language that is being demonstrated and the tools that are used to create and debug procedures. Microsoft support professionals can help explain the functionality of a particular procedure, but they will not modify these examples to provide added functionality or construct procedures to meet your specific requirements. If you have limited programming experience, you may want to contact a Microsoft Certified Partner or the Microsoft fee-based consulting line at (800) 936-5200. For more information about Microsoft Certified Partners, visit the following Microsoft Web site:

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When you use the following sample code, the following information is returned:

•	Computer name.
•	Logon name.
•	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 under normal circumstances.

This information can also be used to isolate problems with database corruption that is associated with the activities of a specific user.

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Procedure

To determine who is logged onto a database, follow these steps:

1.	CAUTION: If you follow the steps in this example, you modify the sample database Northwind.mdb. You may want to back up the Northwind.mdb file and follow these steps on a copy of the database.
2.	Open the sample database, Northwind.mdb.
3.	On the View menu, point to Database Objects, and then click Modules.
4.	Click New.
5.	Type or paste the following code:Sub ShowUserRosterMultipleUsers() Dim cn As New ADODB.Connection Dim rs As New ADODB.Recordset Dim i, j As Long Set cn = CurrentProject.Connection ' The user roster is exposed as a provider-specific schema rowset ' in the Jet 4.0 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.	Save the module as ShowUsers.
7.	Close and then reopen the database.
8.	Press CTRL+G to open the Immediate Window.
9.	Type the following line in the Immediate window, and then press ENTER:`ShowUserRosterMultipleUsers`Note that the Immediate window returns a list of users who are logged onto the database.