Open Data Services (ODS) can provide you with a variety of approaches to building server applications, depending on your development requirements.
Build extended stored procedures. ODS server applications can be integrated as a set of extended stored procedures. This approach can extend SQL Server by way of the Open Data Services API, without providing a separate ODS server application. Instead of running your ODS server application separately and using the ODS Library as a base, you include your application's DLL with the standard SQL Server DLLs and use SQL Server as a base. As a result, each function within your DLL can then be called as if it were a standard SQL Server stored procedure.
Build server applications to extend SQL Server capabilities. ODS server applications designed to extend SQL Server can respond to updates in SQL Server tables, facilitate running external programs, and obtain data from an outside source. For example, this type of server application may be suited to perform functions external to the SQL Server environment, or to capture and reflect current values from the external environment.
Build gateway applications. Gateway applications connect local area network (LAN) clients to external data sources. Gateway applications also can use SQL Server to store or simply deliver data from other systems to LAN clients. Because gateway applications based on ODS can communicate with SQL Server clients, they can take advantage of the client platforms, front-end tools, and network support that SQL Server provides. Gateway applications are particularly useful in mixed database environments because they allow clients to connect to many data sources using a single access library (DB-Library or ODBC) and a single protocol (their LAN transport). This can limit the cost and complexity of connecting to mainframe or minicomputer networks to that of a few powerful servers running gateways.
Build a Windows NT service. You can install an ODS server application as a Windows NT service that responds to Microsoft Windows NT commands such as net start, net stop, and net pause. Windows NT services must use the Win32 API to register with the Service Control Manager.
In addition to selecting the correct approach for developing your server application, you must include specific files, such as header and library files, and follow certain procedures to compile and link the ODS server applications that you develop.
For detailed information about developing ODS server applications, see the Microsoft SQL Server Programmer's Toolkit documentation in the "Database and Messaging Services" section of the Platform SDK.