ADO: ActiveX Data Objects

ADO.NET

ADO.NET is comprised of two main components, DataSets and managed providers. DataSets can store an entire database in memory, while managed providers provide the ability to establish a connection between the data source and a DataSet. In addition, managed providers provide a means of populating, manipulating, and accessing the data within the DataSet.

DataSets

A DataSet is a memory-resident version of a database containing tables, rows, relationships, constraints, and keys. In ADO.NET, all work is done with a DataSet. The DataSet has three main collection classes and numerous child classes belonging to each:

TablesCollection object

A collection of one or more DataTable objects that represent individual tables from the data source. In these DataTable objects, both columns and rows are stored as separate objects. Each DataTable object represents one table within memory. The DataSet is able to persist the contents of the TablesCollection and reload it using XML. The TablesCollection automatically keeps track of any changes made to the data stored in the individual DataTables.

RelationsCollection object

A collection of one or more relations between rows from different tables. Relations can be navigated from one table to another.

Extended Properties object

A collection of user-customized properties such as a password or the time data was last updated.

Managed Providers

A managed provider establishes a connection between a data source, such as SQL Server and DataSet. There are three ...