Once the report connects to a MongoDB database, you create a data set and select the collection from which to retrieve data. A data set can retrieve data from one collection only.

After selecting a collection, you select the fields from which to retrieve data. BIRT maps each selected field to a data set column. Because MongoDB is a schema-less database in which each document can contain a different set of fields, you have the option of specifying the number of documents to scan to compile the list of fields. Scanning documents can be resource intensive. If all the documents contain the same fields, specify one (the default) as the number of documents to scan.