ODBC includes the ability to save Data Source Name (DSN)
information (which basically amounts to persisted connection strings) in a
simple file rather than in the registry.
ActiveX Data Objects
(ADO)provides similar functionality in the form of a Data Link file (*.udl).
Create a Data Link File
- Right-click the directory where you want to store the file,
point to New, and then click Microsoft Data
Link. A new file appears in the directory with the name New Microsoft
Data Link.udl. Rename the file to Pubs.udl. Note: If using Windows 2000, right-click where you want to store the
file, point to New, and then click Text
Document. Change the txt filename extension to
- Double-click the newly created file to set the properties
for the Data Link. You see the following tabs:
Provider | Connection | Advanced | All
- The Provider tab allows you to specify the
provider (the default is Microsoft OLE-DB provider for ODBC drivers). Use the
Default provider, and then click Next.
- The Connection tab allows you to specify
either the data source name that is designated in the ODBC Administrator, or
allows you to provide the connection string.
You can provide
information with one of the following two methods:
Assuming that you have already created a System DSN for the
pubs database, you see the DSN in the drop-down list box (Use Data source).
Choose the DSN for Connection and test it by clicking Test
Connection. You can also build your connection strings.
- Use a predefined DSN name for the connection (it has
all the information to connect to the Data source)
- Build a connection string, or use a known connection
- To complete the settings, click OK . To
learn more about Data Link files, see the Msdasc.hlp Help file, that you can
find in the following directory: C:\Program Files\Common Files\System\ole
- Open a text editor, such as Notepad, and then drag the
DataLink icon to a blank document. You see the connect string
that the data link represents. You can use this connect string in your
Use a Data Link File in Code with an ADO Connection
Using a Data Link file for an ADO connection is fairly simple.
The following is the syntax, using an absolute path:
cnPubs.ConnectionString = "File Name=C:\Path\To\Pubs.UDL;"
For additional information, click the following article number
to view the article in the Microsoft Knowledge Base:
How To Use Data Link Files with the OleDbConnection Object in Visual Basic .NET
For additional information, see the following
Microsoft Web sites:
Article ID: 189680 - Last Review: July 15, 2004 - Revision: 3.6
- Microsoft ActiveX Data Objects 2.0
- Microsoft ActiveX Data Objects 2.1 Service Pack 2
- Microsoft ActiveX Data Objects 2.5
- Microsoft ActiveX Data Objects 2.6
- Microsoft ActiveX Data Objects 2.7
- Microsoft Visual Basic 5.0 Professional Edition
- Microsoft Visual Basic 6.0 Professional Edition
- Microsoft Visual Basic 5.0 Enterprise Edition
- Microsoft Visual Basic Enterprise Edition for Windows 6.0
|kbdatabase kbfaq kbhowto KB189680|