What two types of data providers does ADO.NET supply? What determines which one you should use?

OLEDB,SQL. SQL dataprovider for sqlserver related Insert,update,delete and select operations.Oledd for sql server and other databases.

Refer the link to check the details about various data providers of that comes with .Net Framework 4.5 http://msdn.microsoft.com/en-us/library/a6cd7c08.aspx

The data providers in ADO.NET are as follows 1. .NET framework data provider for SQL Server - For SQL server data access 2. .NET framework data provider for Oracle - For Oracle DB data access 3. .NET framework data provider for ODBC - For ODBC data sources 4. .NET framework data provider for OLEDB - For OLEDB connections 5. Entity client provider - For Entity data model (EDM) data sources 6. .NET framework data provider for SQL Server compact 4.0 - For SQL Server Compact 4.0