The Design of FLEX: A Tolerant and Cooperative User Interface to Databases.
Amihai Motro · International Conference on Human-Computer Interaction · 1987
FLEX is a user interface to relational databases that is tolerant of incorrect input. FLEX never rejects a query; instead, it adjusts to the level of technical expertise its users seem to possess (as judged from their input). In particular, FLEX understands formal queries; salvages incorrect queries if they include enough clues on their intended meaning; suggests educated guesees if it recognizes metadata tokens in the input; or else, it issues browsing requests for recognized data tokens. FLEX is also cooperative. It never delivers null results without explanation and assistance. By following up each failed query with a set of more general queries, FLEX determines whether a null result is genuine (it then suggests related queries that have non-null results), or whether it reflects erroneous presuppositions on behalf of the user (it then explains them).