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Next: Simple Queries Up: Query-by-Example (QBE) Previous: Query-by-Example (QBE)

Basic Structure

  1. QBE has ``two-dimensional'' syntax.
  2. Queries are expressed by example.
  3. Close correspondence with domain relational calculus
  4. Non-procedural.
  5. Queries are expressed using skeleton tables.
  6. User selects the skeletons needed.
  7. User fills in skeletons with example rows.
  8. An example row consists of constants and example elements which are really domain variables.
  9. Domain variables are preceded by an underscore character.
  10. Constants appear without any qualification.
We'll look at examples from the text.

Osmar Zaiane
Tue Jun 9 14:17:04 PDT 1998