The outer layer adds databases with logical files to the flat file system. The RMS programmer is encouraged to use the database system when programming. Databases are organized collections of related data. A good example of a simple database is a book library. In it you have thousands of books with a card catalog indexing all of the books.
More complex databases have interrelations between the data.
A common example of a complex database is an accounting system. Each database consists of one or more logical files. This way, if transaction logging is enabled for the logical file, changes to the logical file are logged. A logical name is a reference to a single file. This can be a logical file name of an RMSfile within a database or the pathname of an RMSfile.