A data object can include any number of data sources, data sets, data cubes, and report parameters. The data objects can be used as predefined data sources in Report Studio. Business users can select already published data objects as data sources, or templates that are designed to use data objects as data sources.
The data objects created for business reports should be designed with the business report requirements in mind. They should provide the data in a structure that is appropriate for business users and for the report elements that users can add to a report.
When you design data objects for business reports always consider the following:
Report parameters in a data object do not link to parameters created in Report Studio, so you typically do not include report parameters in a data object that you create for Report Studio users.
In Report Studio, a chart uses data from a table in a report. The chart does not use data directly from a data set or a cube.
Report Studio cross tab reports require specialized cross tab templates and the data sources used in the templates must be data objects.
Deploying data objects
There are two types of data objects, and either one can be a data source:
Data object design
A data object design specifies a data source and a data set and data cubes. A report developer or data modeler creates the data object design in BIRT Designer Professional. A data object design has a .datadesign extension.
Data object store
A data object store contains the materialized data generated by a data object design. A volume administrator creates the data object store in Information Console administration. A data object store has a .data extension.
If the user uses a data object design as a data source, the report retrieves data from databases and other data sources when it runs. The advantage of this approach is that the report retrieves current data. The disadvantage is that it increases the load on production databases.
If the user uses a data object store as a data source, the report retrieves materialized data from the data object store when it runs. The advantage of this approach is that it does not increase the load on production databases. The disadvantage is that the report may not retrieve current data.
A volume administrator controls which users have access to data objects by assigning privileges on the .datadesign and .data files. If the volume administrator does not want to increase the load on production databases, they can give users access to .data files but not .datadesign files.
To deploy a data object, a report developer, data modeler, and volume administrator cooperate in performing the following tasks:
A report developer or data modeler creates a data object design in BIRT Designer Professional.
The report developer or data modeler places the .datadesign file in the BIRT Resource folder.
The report developer or data modeler publishes the .datadesign file to the iHub /Resources folder.
A volume administrator schedules a job for the .datadesign file that generates a .data file.
A volume administrator assigns privileges for users on the .datadesign and .data files. To give a user access to a .datadesign file, assign read and execute privileges. To give a user access to a .data file, assign read privilege.
Deploying cross tab templates
A user creating a cross tab report must use a template that contains a cross tab element. The cross tab template that installs with iHub resides in <iHub install directory>\modules\BIRTiHub\iHub\Jar\BIRT\platform\plugins\org.eclipse.birt.resources_<version>\templates\crosstab.rpttemplate. A template developer can modify this template or create a new one.
Report parameters in a data object do not link to parameters created in Report Studio, so you typically do not include report parameters in a data object that you create for Report Studio users.