RE: Does SQLClient and OLEdb class share the same func...
No they are entirely different. Each has its own functionality. With OLEDB we can connect to any Datasource while SqlClient can be used to connect to Sql Server Database Only.
RE: Does SQLClient and OLEdb class share the same func...
Yes functionality wise both are *almost* same however there object models differ. SQLClient class has XML capabilities which are a part of feature set of SQL Server.
RE: Does SQLClient and OLEdb class share the same functionality
sqldata provider is a native provider for the sqlserver developed by micrsoft it contains all native drivers that gets connected to the sqlserver. Where as oledbprovider is to make access to any database so it performs some what less efiiciency then that of the sqlclient. It's the best way of using native drivers provider i.e sqlclient when using sqlserver and for any databases other then the sqlserver those don't have a dataprovider it's better to use the oledbprovider.