By using parameter fields that enable business users to select from a list of one or more parameter field values (such as district, country, or account type), you can make reports more valuable for the business users while limiting the volume of data that the report retrieves. For example, a sales report is likely to be more valuable for a sales professional if it allows him to select his specific territory or district, while the report runs more efficiently because it retrieves only the desired data and not an unnecessarily large data set. Parameter fields can prompt users for a variety of information that can be used in a number of flexible ways within reportsgood examples include controlling the sort order, grouping order, record selection (filter), report title and descriptions, report language, alerting thresholds, formula inputs, and so on.
Parameter fields prompt report users to enter information by presenting a question that the user must answer before the report is executed. The information that the user enters determines what appears in the resulting report and also how that report is formatted and presented.
One of the greatest benefits of parameter fields for report designers is the opportunity to have a single report service a large audience while also empowering the users to personalize the information they are viewing within the report. Parameter fields can be used in coordination with record selections so that a single report can be segmented many different ways. Parameter values that business users enter can also be used within record selection formulas to determine what data is retrieved from the database.
For example, consider a World Sales Report for a large organization. This report could potentially include a tremendous amount of data. Not only is the report itself large, but also many of the business users are not concerned with the entire worldwide scope of the sales data. Rather than allow each salesperson to generate the report to include worldwide data, you can include a parameter dialog that asks the salesperson to select from a list of available countries, as shown in Figure 5.1. The report would then return the results for only these specific countries. Thus, by using a parameter field to enable the salespeople to select from a list of countries, the report becomes more valuable for the business users while also limiting the scope of the query by using the selected parameter value(s) to filter the report and reduce the volume of data retrieved.
Figure 5.1. Prompts enable business users to select values to populate the parameter field.