L+: uma linguagem para definição de banco de dados

Abstract

A data modeling discipline based on Predicate Calculus is presented. Sets and types are defined using declared instances or through the specification of expressions. Correspondences can be formed over the instances of those set or over the instances of other correspondences, introducing the possibility of composition. Derived data, either as sets or correspondences are obtainable. Schema constraints are namea' and specified through formulas. Aggregate operators are declared with domain and range sets. Examples and the syntax of the language are provided.