NoSQL databases are often categorised under four main types. Some databases are a mix between different types, but in general, they fit under the following main categories.
A column store database is a type of database that stores data using a column oriented model.
A column store database can also be referred to as a:
A document store database (also known as a document-oriented database, aggregate database, or simply document store or document database) is a database that uses a document-oriented model to store data.
Document store databases store each record and its associated data within a single document. Each document contains semi-structured data that can be queried against using various query and analytics tools of the DBMS.
A key-value database (also known as a key-value store and key-value store database) is a type of NoSQL database that uses a simple key/value method to store data.
The key-value part refers to the fact that the database stores data as a collection of key/value pairs. This is a simple method of storing data, and it is known to scale well.
NoSQL is a term that refers loosely to a particular type of database model, or database management system (DBMS).
NoSQL is a very broad term that doesn’t refer to one particular database model. Rather, it refers to a whole variety of different models that don’t fit into the relational model.
Although NoSQL databases have been around since the 1960s, it wasn’t until the early 2000s that the NoSQL approach started to pick up steam, and a whole new generation of NoSQL systems began to hit the market.
A graph database is a database that uses a graphical model to represent and store the data.
The graph database model is an alternative to the relational model.
In a relational database, data is stored in tables using a rigid structure with a predefined schema.
In a graph database, there is no predefined schema as such. Rather, any schema is simply a reflection of the data that has been entered. As more varied data is entered, the schema grows accordingly.