External report generators are stand-alone software packages that produce reports from a variety of data sources. In addition to handling a wide range of database and flat file data sources, many of the report generator packages will provide a component that interfaces the report engine directly into your application. By doing so you leverage the power of the selected report engine without having to code all of the related processes.
External report engines will often have a wider variety of tools for the developer to work with in creating a report. The cross-tab report, for example, can be created with a drop-in component in some reporter environments, saving you the trouble of coding all of the supporting processes that are necessary to implement this with a QuickReport. Many paper styles and non-paper destinations are automatically available to your report, allowing your application to generate such output as HTML documents and fax files.
The external report tools are also very useful in extending the capabilities of your application to the end user. By carefully documenting your data files and relationships, you enable the user to create custom reports on their own based on the data collected through your application. Rather than them waiting for you to update the application with every report request received, the users are able to satisfy their own report needs quickly and efficiently Plan for the necessary training to
make the most of this opportunity though; it may take the users may take some time to understand the intricacies of your data and the report tool.
There is a cost associated with integrating most report engines into your application. When your users press the Print button, they expect instantaneous response to their request. The overhead of loading the engine will generally take quite a bit longer than an internal solution, so you are going to need to take extra care to manage this expectation with your users. The installation of the application is also going to expand a bit as well when the engine's DLLs are included with your distribution disks.
We have covered reporting and output from the simplest to relatively complex. Though the report design aspects of an application are often left until last, your application can benefit from moving this task up on the time line so that much more of the application's core can be designed to implement the output needs. Be sure to explore the full range of reporting options with your users; there may be a lot of infor-formats that they have not considered.
This chapter brings to a close the development tools segment of the book. We have explored the components, tools, and programming strategies utilized when developing database applications in Delphi. The chapters that follow will focus on specific topics of interest to the database developer.
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