Page 303 - DCAP408_WEB_PROGRAMMING

Unit 14: Database Connectivity

 Click “Add” to add a DSN less entry, and then on “Microsoft Access Drive”. If “Microsoft Notes
Access Driver” does not appear on the list, you possibly have not installed Microsoft
Access 7’s, 32 bit ODBC drivers.
 At the “Data Source Name” enter “UserDB1”, then “Select” the database - you can use
“Browse” to select the database users.mdb. With “users” directory created for the application
the path to the database c:\inetsrv\wwwroot\users\users.md

Connecting to the Database - Method

This is done to maintain a connect throughout the user’s session. The connection is closed when
the session ends. This is controlled by the Global.asa file. Each ASP-Based intranet application
can have one global.asa file located in the root directory of the application. The global.asa has
four events - Application-Start , Session-Start, Application-End and Session-End. The connect to
the database for the session is in the Session-Start event , with Session-End being the event used
to close the connection.

!
Caution The language or script being used is VBScript and the ASP is to run on the server.
Connect string in Global.asa
Conn.Open “UserDB1”, “userdblogin”,”userdbpassword”

“Conn” is connect to the database that can be used throughout the session to the DSN less entry
UsersDB1 with a login of “userdblogin” and a password of “userdbpassword”.
The first post-startup request is made to the web server for any *.asp file in an application causes
the Global.asa to be read. So the moment a request is made to any *.asp in the directory in which
the intranet application is stored a connection is established with the DSN less UserDB1. Following
that the default document, in this case default.asp is processed.

Example: Connecting to database method
SUB Session_OnStart
‘—— Open ADO connection to database
Conn.Open “UsersDB1”, “userdblogin”,”userdbpassword”

END SUB

14.1.1 DSN Less

Requires no server setup, just a carefully constructed connection string as demonstrated below.
DSN less connections demand that that you know the name of the file (i.e. file based databases
like Access, Paradox, FoxPro, etc.) or the address of the data server (SQLserver, for example).
Armed with appropriate information you could open a data source without a DSN! This is faster
than a system DSN* since it saves a trip to read the registry each attempt.
To create a DSN-less connection with a Server.MapPath expression:
1. Upload the database file to the remote server.
Make a note of its virtual path—for example, /jsmith/data/statistics.mdb.
2. Open one of your site’s pages in UltraDev and choose Modify > Connections.

The Connections dialog box appears.

LOVELY PROFESSIONAL UNIVERSITY 297