Queryng data in NoSQL databases

Abstract

The goal of this paper is to give an overview of fundamental concepts and types of NoSQL databases, to show some examples of database queries, some related research, and the implementation of those queries in an original practical example. The introduction is a brief representation and description of the NoSQL database. There are also several comparisons of NoSQL database with the relational database. The next chapter contains a review of the basic NoSQL databases and their prototypes. In each of the following subchapters, the types of NoSQL databases are described in more detail and various queries which can be performed over them are presented. In the last chapter there is also a practical example of querying one of these databases.

A COMPARATIVE STUDY AMONG THE MAIN CATEGORIES OF NoSQL DATABASES

“…A query language is a set of structured statements used to define, manipulate, and retrieve data in a database. NoSQL DBMS don't use SQL that is used as the query language of the relational databases [33]. NoSQL doesn't have a standard query language and the majority of the NoSQL DMNSs providers have invented their own query languages [34].…”

“…This brings some difficulty when a user wants to switch from one NoSQL DBMS to another. For example, Cassandra supports Cassandra Query Language (CQL), Mongo DB supports the mongo query language, etc [33]. This has created a critical need to develop a common query language that can support a variety of NoSQL database users.…”