Queries = examples + counterexamples

Database queries can be expressed as unordered collections of examples and counterexamples. The resulting languages are intuitive, first order complete, and applicable to a variety of data models including relational, object oriented, and visual models. This class of languages based on examples and counterexamples employ a minimal number of constructs with no sequencing or nesting of the constructs implied, allowing a simple and uniform theoretical analysis of their syntax, semantics, and completeness.