Database Systems, Quo Vadis?

Databases have been around for more than 50 years. Codd’s relational data model from 1970 decoupled the form of data from the physical storage of that data and introduced two important formal query languages: relational calculus and relational algebra. At that time, the research was focused on development of non-procedural query languages whose expressive power is closer to computational completeness. The SQL language has become an “intergalactic dataspeak” supporting objects, XML data, and even recursion. A lot of effort was devoted to the design of database schemas including integrity constraints ensuring database consistency. We developed new approaches to database modelling both at the conceptual and data levels based on a simple theory of types, and used typed lambda calculus for querying a functional database. This approach we used later in the world of data warehouses, XML databases, and others. Our research was also focused on implementation techniques, e.g., how to store and query XML data in a column-oriented storage.

The difficulties in scaling up SQL databases for online, web-scale processing have led to the creation of NoSQL systems in the 2000s. But key-value, column, document, and graph databases mostly do not use database schemas, integrity constraints, high-level query languages, and do not guarantee properties typical for transaction processing in traditional databases. Of course, this is unsuitable for many applications. The next decade offers a NewSQL databases - modern relational databases that seek to provide the same scalability as NoSQL, but guarantee the same transactional support as traditional DBMSs. We will show this diverse database world and some possibilities how to approach it within an integrated database architecture.