NoSQL datastore systems are a new generation of non-relational databases. More than fifty NoSQL systems have been already implemented, each with different characteristics — especially, with different data models and different APIs to access the data. In this paper we describe and compare the data models and operations offered by a number of representative NoSQL datastores, which we have directl...

NoSQL data storage systems have become very popular due to their scalability and ease of use. This paper examines the maturity of security measures for NoSQL databases, addressing their new query and access mechanisms. For example the emergence of new query formats makes the old SQL injection techniques irrelevant, but are NoSQL databases immune to injection in general? The answer is NO. Here w...

T he exponential growth of the Internet has resulted in an explosion of data sources, creating storage and data-usability problems. Furthermore, an increase in the number of data types has created challenges in terms of storing and manipulating unstructured data. These issues have lead companies and open source communities to build new tools, known as NoSQL systems or “key-value-store” systems,...

NoSQL databases are an important component of Big Data for storing and retrieving large volumes of data. Traditional Relational Database Management Systems (RDBMS) use the ACID theorem for data consistency, whereas NoSQL Databases use a non-transactional approach called BASE. RDBMS scale vertically and NoSQL Databases can scale both horizontally (sharding) and vertically. Four types of NoSQL da...

The paper introduces Strudel, a development and execution framework for transactional workloads both on SQL and NoSQL systems. Whereas a rich set of benchmarks and performance analysis platforms have been developed for SQLbased systems (RDBMSs), it is challenging for application developers to evaluate both SQL and NoSQL systems for their specific needs. The Strudel framework, which we have rele...

NoSQL data stores are commonly schema-less, providing no means for globally defining or managing the schema. While this offers great flexibility in early stages of application development, developers soon can experience the heavy burden of dealing with increasingly heterogeneous data. This paper targets schema evolution for NoSQL data stores, the complex task of adapting and changing the implic...

The main aspect of NoSQL data stores is “shared nothing” horizontal scaling, which enables them to support a large number of simple read/write operations per second. Most of the NoSQL data stores generally do not provide strict ACID properties. The idea is that by giving up strict ACID constraints high performance and scalability can be achieved. The objective of this paper is to study and comp...

NoSQL databases offer a powerful and flexible means of querying non-relational data. However, leading NoSQL systems typically achieve high performance goals while minimizing support for traditional data management services and defying the establishment of solid formal models. In particular, the systems generally shun tools and design principles rendered conventional by the long history of RDBMS...

NoSQL databases are popular in agile software development, where a frequently changing database schema imposes challenges for the production database. In this demo, we present Darwin, a middleware for systematic, tool-based support specifically designed for NoSQL database systems. Darwin carries out schema evolution and data migration tasks. To the best of our knowledge, Darwin is the first too...