Microsoft® SQL Server™ is a multiuser relational database management system (DBMS) that runs on the Microsoft Windows NT™ operating system. Structured Query Language (SQL) is used to access data in a SQL Server database. Client workstations communicate with SQL Server across a network, such as a Windows NT Server, Novell® NetWare®, Banyan® VINES®, or TCP/IP network.
The SQL Server driver enables applications to access data in Microsoft SQL Server databases through the Open Database Connectivity (ODBC) interface.
Both 16- and 32-bit versions of the ODBC SQL Server driver are available.
Note that the 32-bit ODBC SQL Server driver is thread safe. The driver will serialize shared access by multiple threads to shared hstmt, hdbc, and henv objects. However, the ODBC program is still responsible for keeping operations within statement and connection spaces in the proper sequence, even when the program uses multiple threads.
This is the application/driver architecture for 16-bit environments:
Note Thunking means intercepting a function call, doing some special processing to translate between 16-bit and 32-bit code, and then transferring control to a target function.
Application (16-bit) Application (32-bit in Win32s)
| |
32-bit Thunking Driver Manager
(ODBC32.DLL)
| |
ODBC Universal Thunking DLL
(ODBC16UT.DLL)
| |
ODBC Driver Manager
(ODBC.DLL)
|
ODBC Cursor Library (optional)
(ODBCCURS.DLL)
|
SQL Server Driver (16-bit)
(SQLSRVR.DLL)
|
Net-Library
(DBNMP3.DLL, DBMSSPX3.DLL, etc.)
|
Network Software
(Windows NT, Windows for Workgroups, Novell NetWare, etc.)
|
Microsoft SQL Server
This is the application/driver architecture for 32-bit environments:
Application (16-bit) Application (32-bit)
| |
ODBC Driver Manager ODBC Driver Manager
(ODBC.DLL) (ODBC32.DLL)
| |
ODBC Cursor Library (optional) ODBC Cursor Library (optional)
(ODBCCURS.DLL) (ODBCCR32.DLL)
| |
16-Bit ODBC Generic Thunking DLL
(ODBC16GT.DLL)
| |
32-Bit ODBC Generic Thunking DLL
(ODBC32GT.DLL)
| |
SQL Server Driver (32-bit)
(SQLSRV32.DLL)
|
Net-Library
(DBNMPNTW.DLL, DBMSSPXN.DLL, etc.)
|
Network Software
(Windows NT, Windows for Workgroups, Novell NetWare, etc.)
|
Microsoft SQL Server