New features in ADO.NET 2.0

1. MARS
The new Multiple Active Result Sets (MARS) feature in ADO.NET 2.0 can have multiple active commands on one connection. By using MARS, you can open a connection to the database, create a new command and process some results, create a second command and process those results, then go back to the first command and process more results. No blocking happens between the commands that share the database connection. You can use MARS support only with SQL Server 2005 systems.
2. Schemas
In ADO.NET 2.0, Microsoft has added a set of features to the standard managed code classes that you can use as an API to query database schemas and obtain information about the tables, stored procedures, data types, users, and other content of a database.
3. Bulk Insert
The SqlBulkCopy object provides a high-performance method for transferring database objects between databases or SQL Server systems. However, the object doesn't connect to the file system and thus can't be used to import flat files to SQL Server.
4. Query Notification
If records in the underlying database table change, then your Web application will display old, inaccurate data. ADO.Net 2.0 provides us with the feature where in the cache can be invalidated and the data is re-loaded in the cache when the request is made if the underlying data changes before the cache expires. SQL Server 2005 has got a SQL Broker Service feature where-in it will notify the web application that the data has changed. This helps in relieving the web application to poll to the SQL Server 2005 to check for data changes.
5. New Data Set
The indexing engine for SQL Server 2005 has been re-written which helps in reading the data much faster than earlier version. The DataTable is independently serializable and can be used in both web service and remoting scenarios. The DataTable now supports the basic methods for XML, just as the DataSet does.
6. XML Data Type Support
XML data type is just like INT or VARCHAR, and SQL Server 2005 allows in-place querying and processing of this data type using a series of XML-specific functions. There is also support for storing collections of XML schemas in the database, enabling database-based schema validation.
7. Asynchronous Support
Asynchronous support lets client applications submit queries without blocking the UI. ADO.NET 2.0 lets server applications issue multiple database requests on different threads. The support works with SQL Server 2005, SQL Server 2000, and SQL Server 7.0.