ADO.NET was designed to meet the needs of a new programming model: disconnected data architecture, tight integration with XML, common data representation with the ability to combine data from multiple and varied data sources, and optimized facilities for interacting with a database, all native to the .NET Framework.The ADO.NET DataSet is a memory-resident representation of data that provides a consistent relational programming model regardless of the source of the data it contains.
Datasets in Microsoft.Net - Adding DataColumn Objects (Page 7 of 8 )
Once you have a new DataTable, you’ll want to add some DataColumn objects. Click on the leftmost cell in the first row in the box that represents your new DataTable in the XML schema designer. This should make an arrow appear just to the right of that cell. Click on the arrow and you’ll see a list, similar to the one shown in next figure, of available items you can add to the DataTable. To add a new DataColumn, select Element from the list and then specify the name for your new DataColumn. The text you enter will be stored in the DataColumn object’s ColumnName property.
To set other properties on a DataColumn, select the desired column in the XML schema designer. Next figure shows part of the list of available properties that appears in the Properties window when you select a column in the XML schema designer. You’ll notice that some of the properties are specific to the DataColumn and others are more applicable to XML elements. Some properties that were added to the ADO.NET object model late in the development cycle, such as the DataColumn object’s MaxLength property, are not available through this interface.