Working with data sets (1)

The centerpiece of any software solution using ADO+ is the data set. A data set is an in-memory copy of database data. A data set contains any number of data tables, each of which typically corresponds to a database table or view. A data set constitutes a "disconnected" view of the database data. That is, it exists in memory without an active connection to a database containing the corresponding tables or views.

At run time, data will be passed from the database to a middle-tier business object and then down to the user interface. To accommodate the exchange of data, ADO+ uses an XML-based persistence and transmission format. That is, to transmit data from one tier to another, an ADO+ solution expresses the in-memory data (the data set) as XML and then sends the XML to the other component.

The following illustration shows the major components of an ADO+ solution.

Figure 2. ADO+ Architecture

To make working with data easy in Visual Studio 7.0, there are many new features. For the hardcore XML developer, Microsoft has included a rich color-coded XML Designer with statement completion and tag completion.