Chapter 1 Introducing EAServer

Result-set support

EAServer methods can return tabular data to the calling client. This feature can be useful for the following reasons:

Use with data-aware controls Some front-end tools provide objects that can automatically display a result set. For example, if using PowerBuilder, you can return results in a or DataStore object from component methods and display the results using a DataWindow® control in the client. PowerBuilder's DataWindow technology, available in both Web and PowerBuilder clients, allows you to display result sets and synchronize updates with a minimum of coding.
Efficiency For tasks that require returning tabular data, using an EAServer result set is the most efficient alternative. Common uses of result sets include menu and pick-list population. For example, in an online clothing catalog, you need to list in-stock sizes for each item.

The EAServer result set allows data to be sent all at once (rather than requiring a get-next-row method and one client-server round trip per method). A large EAServer result set can be sent with less overhead than is required to encapsulate tabular data as an object and send a serialized version of the object to the client.

Each component model provides an interface that allows you to define result sets from scratch or to forward results from a remote database query directly to the client. See Chapter 25, "Sending Result Sets," in the EAServer Programmer's Guide for more information.

For information on using the PowerBuilder DataWindow, see the PowerBuilder Application Techniques manual.