What is NoSQL DB

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NoSQL

NoSQL database management systems are alternative systems to the established relational database management systems, i.e. systems that do not use a relational data model and therefore usually do not provide an SQL interface.

Such systems have been around for a very long time, but the term NoSQL has been used since around 2009 to characterize these rapidly growing systems. The main reason for the renewed interest is the increasing demands on databases, for which relational models are not always the ideal solution. The new requirements are, on the one hand, the enormous amounts of data that arise in large web applications and other big data scenarios, but also availability and fault tolerance.

The NoSQL movement often understands the term as "Not Only SQL", and wants to express that relational database management systems are very well proven tools, just not optimal for all purposes.

Classification

Naturally, it is difficult to classify database management systems that are only defined by the absence of features. The alternative approaches to a solution are very different and with each classification you will find systems that are difficult or impossible to classify. Usually, however, a distinction is made between the following classes:

advantages

Due to the different classes of NoSQL systems, none of the advantages that apply to all can be named. In detail, however, it is always a combination of the following points:

Methods

These advantages are mainly achieved with the following means, but each of them also has disadvantages:

  • Alternative approaches to normalized, relational data models
  • Abandonment of one or more of the ACID criteria
  • Less powerful data retrieval mechanisms

Additional information

You can find more information in the article NoSQL - Brave New Database World or Temporary Hype? (PDF) from solid IT.