iReport Ultimate Guide - Nimsoft Library

Flash ChartsFigure 13-22 Entering the expressions for a new entityEach expression controls a different aspect of the way data is displayed and grouped in the chart. Table 13-4 details theexpressions.Table 13-4Chart dataset expressionsExpression Type DescriptionSeries Expression String Identifies the series name to which the item refers. With a chartthat uses only a single series, set the value of the expression tothe empty string (""). To allow for series expressions that are setto null, even if in a single series, each value is considered aseparate series and is displayed in a different color.The figure below shows the effect of the expression setting. Inthe chart on the left, the series is set to null; in the chart on theright, it is set to the empty string "".Category Expression String Evaluates the category to be charted along the X axis; forexample, country name. When using multi-series charts, thecategory names should be present in one or more series. Forexample, in a chart that shows revenue over several years andseveral countries, the revenue is the value, years are the series,and countries are category names that are present in one ormore series.259