ADO vs ADO.NET vs OLE DB vs ODBC [数据提供程序之间的差别]

What are the Microsoft Data Access Components?
The Microsoft Data Access Components (MDAC) are the key technologies that enable Universal Data Access. Data-driven client/server applications deployed over the Web or a LAN can use these components to easily integrate information from a variety of sources, both relational (SQL) and non relational. These components include Microsoft ActiveX Data Objects (ADO), OLE DB, and Open Database Connectivity (ODBC).T