2. How the client interacts with SQL Server

The complete process of sending a Transact-SQL statement from the client to the SQL Server server, processing the result, and returning the result to the client is as follows:
(1) Microsoft ole db for SQL Server provides Program , SQL Server ODBC driver or DB-library DLL to generate the TDS data packet.
(2) TDS data packets are transmitted to the SQL Server Client. Net-library.
(3) The client net-library encapsulates the TDS data packets as network protocol data packets.
(4) on the server, the server net-Library receives network protocol packets. ODS (Open Data Services) is responsible for extracting the TDS data packets and passing the results to the relational database server.
(5) The Relational Database Server is responsible for processing the content of the TDS data packets.
(6) If you need to return the result to the client, ODS will generate the processing result and pass it to the Server Net-library.
(7) The Server Net-library encapsulates the TDS data packets as network protocol data packets and then transmits them back to the client. Net-library.
(8) The client net-library restores the network protocol data to the TDS data packet and transfers it to the upper-layer database interface, for example, Microsoft ole db provider, SQL Server ODBC driver, or DB-library DLL.
(9) Microsoft ole db provider, SQL Server ODBC driver, or DB-library DLL restores the TDS data packet to a "result set" that is acceptable to the application ".
No matter whether the application that accesses SQL Server is on the same single machine as the SQL server instance, the communication between the application and the SQL server instance goes through the above process.