It is not so easy to design a query method that remains simple and avoids the use of an extended idiom and complex syntax. The idea was to avoid something like SQL because it is not be necessary to know the file- and field names to use the database. Therefore the query modes have been designed to hide as much as possible the database details.
In BDA four different approaches have been tried in an effort to minimize the learning and keep the typing at a low level. These four modes can be schematized as: