A BIRT data object design file contains all the information to connect to an external data source, retrieve data from that data source, and structure the data in a way that supports business analysis. Data objects organize data in tables, called data sets, or in multiple dimensions called data cubes. Parameters can be added by the BIRT report developer to request values for filtering or to use with a script inside the data object design file. Figure 4‑2 shows a data object design file opened in BIRT Designer Professional.

BIRT data object design files do not store data. When a gadget requests data from a data object design file, one or more queries are sent to the external data source to retrieve data.

Data selection gadgets, such as a list and data visualization gadgets, such as a chart, use BIRT data objects as the source of the data that they display on the dashboard. These files are stored in the Encyclopedia volume’s resource folder. Data object design files use the file-name extension .datadesign.