Design issues and first experiences with a visual database editor for the extended NF2-data model

The authors describe a visual database editor for the extended NF ² (eNF²)-data model for simple tasks like browsing the database, data entry, and editing. The editor´s interface, called a finger, is based on the paradigm of a two-dimensional cursor, and can be used even by casual users. The system, named Escher, serves as a research vehicle for self-referencing methods in the implementation of database systems. One aspect, a fixpoint `scheme-of-schemes´, is discussed in detail, and its visual representation, as produced by the prototype, is shown. Other topics that are treated include the semantics of the cursor movement and new additions to the eNF² data model, such as scripts and links. Preliminary results of the use of Escher are reported