Among the data sources in your Discovery Framework application, you must always include a default data source. This data source is automatically assigned to all data-source-backed components when they are initially added to a page.
When you initially start the Discovery Framework, the id of this data source is "default." While this setting remains unchanged, you must include a data source with the id “default." Upon installation, a default.json data source file (with an implicit id of "default") is included in the endeca-portal\data\endeca-data-sources directory.
Alternatively, you can change the default data source name to that of another data source file. To do so: