An approach to information export from database for complex master-detail table hierarchies into a single flat table form

When developing a database client application it is usually required to implement a capability to export information from database tables into some simple data-exchange representations of tables like the CSV (Comma-Separated Values) format. It is very straightforward to implement the export for a single database table. But some information about the records of a master table may be represented by the records from, sometimes, several detail tables, so the resulting CSV table would be incomplete without this information. We develop AIS (automated information systems) using declarative specifications of database applications (SDA). The AIS’es are implemented using general algorithms, which are directed by the specifications. In this article we’ll consider the approach to generation of flat tables from the master-detail groups of tables, which allows users to represent compactly the data from a hierarchy of tables related by the master-detail relationships and to select conveniently which kind of information to include into the resulting table.