About displaying data in charts
You use the same kind of data sources for a chart as you do for other report items. You can open a connection to a data source and create the data set for a chart from Data Explorer, or you can use an existing data set. You learned to create a data set in Task 4: “Build a data set” in Tutorial 1: “Building a simple listing report.” The next section describes how to specify a data set used by another report item or a container.
How you retrieve and arrange data in a chart can be different from the way that you use data elsewhere in BIRT. As you learned in the chart tutorial, you provide expressions that organize the data into visual elements, such as bars or lines. After you preview the chart, you may think that you need additional or different data to make the meaning of the chart complete or clear. For example, you can group data values or use chart axis settings to modify the formatting, range, or scale of the data that the chart displays.