No relation: the mixed blessings of non-relational databases

This paper investigates a new class of database systems loosely referred to as "non-relational databases," which offer a subset of traditional relational database functionality, in exchange for improved scalability, performance, and / or simplicity. We explore the differences in conceptual modeling techniques, and examine both the advantages and limitations of several classes of currently available systems, using running examples of real-world problems as implemented in both a traditional relational database model, as well as several non-relational models.