Getting Started With Microsoft Data Access Components

Microsoft® Data Access Components (MDAC) provides easy-to-use, programmatic access to all types of data throughout the enterprise. Data-driven client/server applications deployed over the Web or a LAN can use these components to easily integrate information from a variety of sources, both relational (SQL) and non-relational. Microsoft Data Access Components consist of ActiveX™ Data Objects (ADO) and the Remote Data Service (RDS), the Microsoft OLE DB Provider for ODBC, Open Database Connectivity (ODBC), and ODBC drivers for Microsoft SQL Server, Microsoft Access and other desktop databases, and Oracle databases. All of these components are released, documented, and supported together.

The Microsoft® Data Access Components (MDAC) support a number of different application scenarios. How you use MDAC depends on the scenario in which you deploy your application. MDAC supports the following scenarios:

Intranet Client/Server

When deploying an intranet ("behind the firewall") application via Microsoft Internet Information Server 4.0 (IIS) and Microsoft Internet Explorer 4.0, you can take full advantage of the power and flexibility of ADO and RDS. A wide variety of application scenarios are possible:

Use ADO in a compiled .dll (written in Microsoft Visual Basic®, Microsoft Visual C++®, or Microsoft VisualJ++™) to access data; use RDS to extend data to the client.
Use ADO in Microsoft Visual Basic, Scripting Edition (VBScript) or JScript™ to access data on an ASP page, and use RDS to extend data to the client.
Use the default business object — RDSServer.DataFactory — to connect RDS directly to the data source. No server-side code is required.

Internet Client/Server

If your target client could be on a platform other than Windows®, such as an Internet application where you want to expose data to any Web browser, regardless of the platform, you cannot use RDS. However, you can still use ADO to expose data via HTML controls through an ASP page on Internet Information Server. Because any data manipulation, scrolling, updates, and so on take place on the server, performance will be slower because more round trips are required between the client and the server.

Microsoft Windows LAN Client/Server

A variation of the intranet scenario, in this case Windows-based clients connect to the server using the DCOM (Distributed Common Object Model) protocol instead of HTTP. As with the HTTP intranet scenario, the server and client can take advantage of ADO and RDS, respectively. The biggest difference is that a custom client-side executable must be installed on each client machine.

Stand-alone

In a stand-alone application, you use the ADO interfaces and an OLE DB data provider in conjunction with a language such as Visual Basic, Visual C++, or VisualJ++. ADO is a dual-interface COM library, so you can use it as part of any Windows-based application.