SQL数据读取器SQL Server核心实现

Question

while i am learning core of System.Data i tried reading MSDN Core implementation code.

in the same way i could call some low level system dll (win32) to read hdd drive info i was trying to test and learn from system data SQL through the above MSDN link, as i am trying to break it down i couldn't find the entry point. my question is:

what is the minimal code required to connect to SQL SERVER and return some data ?

*either with c# _preferred or c++ (if there's noticeably less overhead)

Edit: using only some parts From the System.Data SqlDataReader Rather than whole class.

Answer 1

System.Data.SqlClient (.NET Provider for SQL Server) is a low-level "DLL". It communicates with SQL Server using the low-level TDS protocol similarly to ODBC and OLEDB. The difference is SqlClient is a managed provider whereas ODBC drivers and OLEDB providers are native (unmanaged). The unmanaged driver/providers provide a call-level interface and COM interface respectively, which is intended to be used from native code like unmanaged C++.

All these providers/drivers communicate with SQL Server using the low-level TDS protocol. The TDS protocol itself is not directly exposed. System.Data.SqlClient.SqlDataReader is the lowest level data access from managed code and provides the highest performance for .NET applications.

Answer 2

Here is a link to the beginner's guide to connecting to SQL Server with C#:

http://www.codeproject.com/Articles/4416/Beginners-guide-to-accessing-SQL-Server-through-C

But you should make sure to properly separate code-responsibility so that you're not rewriting the same code all over the place. Have a class that interfaces with the database (dataaccess layer) so you can just call it from all of your business objects and static classes.