When you develop a DataServer application, you can design it either to emphasize portability across data sources or to optimize the strengths of the DataServer's interaction with a MS SQL Server database. For example, you might write a query that gives you consistent results across databases or one that takes advantage of MS SQL Server's cursor management functionality.

In addition to influencing how DataServer applications perform through queries, you can control how the DataServer processes queries on a statement-by-statement basis. Some of the DataServer's default behavior might not be optimal for the application you are designing. The QUERY-TUNING phrase and startup and connection parameters give you the ability to control query processing.

Information on query tuning appears in the following locations:

• The remaining sections of this chapter document the QUERY-TUNING phrase.
• For information on tuning queries at compile time and run time, see Query tuning with connection and startup parameters.