Abstract: The concept of versioning was initially proposed for controlling design evolution on computer aided design and software engineering. On the context of database systems, versioning is applied for managing the evolution of different elements of the data. Modern database systems provide not only powerful data models but also complex query languages that have evolved to include several features from complex programming languages. While most related work focuses on different aspects of the concepts, designing models, and processing of versions efficiently, there is yet to be a formal definition of a query language for database systems with versions control. In this work we propose a query language, named Versioned Object Query Language (VOQL), that extends ODMG Object Query Language (OQL) with new features to recover object versions. We provide a precise definition of VOQL through a type system and we prove it safe in relation to a small-step operational semantics. Finally, we validate the

Syntax sugar for FC++: lambda, infix, monads, and more.............. 15

This paper proposes a number of type-system and language extensions to natively support relational and hierarchical data within a statically typed object-oriented setting. In our approach SQL tables and XML documents become first class citizens that benefit from the full range of features available in a modern programming language like C or Java. This allows objects, tables and documents to be constructed, loaded, passed, transformed, updated, and queried in a unified and typesafe manner.