Accessing data in a BIRT report document
A report document is a binary file that contains report design information and cached data. It has the file extension .rptdocument. You can generate a report document from a report design, then use the report document as a data source for other reports. Using data from a report document provides the following benefits:
Faster report-generation time because the report does not have to connect to an external data source, such as a database or web service, to retrieve data.
Reuse of calculated data. If a table or chart in a report document contains calculated data, such as aggregations, that data is available to your report design.
Simplifies report creation. You do not need to gather all the information to connect to an external data source, nor do you need to create the query to retrieve data from the data source. Eliminating these steps is particular useful if data retrieval requires a complex SQL query to get data from a database, or a complex SOAP request to get data from a web service.
A report document provides efficient access to data, but at the cost of data possibly being out of date. It is most useful in cases where connecting to and querying a data source is resource-intensive, or when the data changes infrequently.
As with other types of data sources, for a report to use data from a report document, you must create the following BIRT objects:
A data source that contains the information to connect to a report document
A data set that specifies the data to use from the report document