I.V. Merkeev

Formal query languages are widely used in modern information technology. These languages are employed by software developers to access databases. They are difficult to learn by non-computer specialists. Attempts to create query languages based on a limited natural language have not led to the creation of industrial level systems. This is because a limited natural language lacks in the expressive power of the natural language and is ambiguous. The article describes the unified query language based on the theory of constructive semantics. This language is unambiguous and its expressive power is similar to that of the natural language. The article shows numerous examples of the unified database access language in action. Queries to relational, temporal, spatial and multidimensional databases are presented both in the natural language and in the unified language.