ADO : 1. ADO is base on COM : Component Object Modelling based 2.ADO can’t be integrated with XML because ADO have limited access of XML. 3. ADO is connection oriented means it requires continuous active connection.ADO.Net : 1. ADO.Net is based on CLR : Common Language Runtime based. 2. ADO.Net stores data in XML format i.e. parsing of data. 3. ADO.Net is disconnected, does not need continuous connection.

ADO objects are COM objects. ADO.Net objects are represented using XML

ADO objects have difficulty traveling through firewalls. ADO.Net objects, represented as text (XML), travel easily through all kinds of network restrictions

. ADO recordsets are heavier than the ADO.Net counterparts, datasets.

ADO recordsets can hold data from one data source at a time. ADO.Net datasets can hold data from various sources and integrate the data and write it back to one / several data sources.

ADO.Net dataset represents in memory representation of a database. ADO recordsets is merely a set of rows retrieved from a data source.

Links- http://msdn2.microsoft.com/en-us/library/904fck4k(VS.71).aspx

http://www.informit.com/articles/article.aspx?p=31098&rl=1

http://www.dotnetspider.com/qa/Question34271.aspx

http://dnjonline.com/article.aspx?ID=iss22_essentials2

http://www.interviewcorner.com/Answer/Answers.aspx?QuestionId=1025&MajorCategoryId=1&MinorCategoryId=2

ADO.NET is stateless mechanism. I can treat the ADO.Net as a separate in-memory database where in I can use relationships between the tables and select insert and updates to the database. I can update the actual database as a batch.