  The demanding requirements of the new Big Data intensive era raised the need
for flexible storage systems capable of handling huge volumes of unstructured
data and of tackling the challenges that traditional databases were facing.
NoSQL Databases, in their heterogeneity, are a powerful and diverse set of
databases tailored to specific industrial and business needs. However, the lack
of theoretical background creates a lack of consensus even among experts about
many NoSQL concepts, leading to ambiguity and confusion. In this paper, we
present a survey of NoSQL databases and their classification by data model
type. We also conduct a benchmark in order to compare different NoSQL databases
and distinguish their characteristics. Additionally, we present the major areas
of ambiguity and confusion around NoSQL databases and their related concepts,
and attempt to disambiguate them.
