Database systems
Relational database
A relational database is a collection of information that organizes data points with defined relationships for easy access. In the relational database model, the data structures -- including data tables, indexes and views -- remain separate from the physical storage structures, enabling database administrators to edit the physical data storage without affecting the logical data structure.
NoSQL database
This type of database is an alternative that's especially useful for large, distributed data sets. NoSQL databases support a variety of data models, including key-value, document, columnar and graph formats.
Graph database
Expanding beyond traditional column- and row-based relational data models; this NoSQL database uses nodes and edges that represent connections between data relationships and can discover new relationships between the data. Graph databases are more sophisticated than relational databases.
Distributed Database
Unlike a centralized database system , in distributed systems , data is distributed among different database systems of an organization .
Object relational database (ORD)
An ORD is composed of both a relational database management system (RDBMS) and an object-oriented database management system (OODBMS). It contains characteristics of both the RDBMS and OODBMS models. A traditional database is used to store the data. It is then accessed and manipulated using queries written in a query language, such as SQL. Therefore, the basic approach of an ORD is based on a relational database.
Network databases
It is the database that typically follows the network data model . Here , the representation of data is in the form of nodes connected via links between them .
Hierarchical databases
Data get stored in the form of records that are connected via links . Each child record in the tree will contain only one parent . On the other hand , each parent record can have multiple child records .
Centralized Database
It is the type of database that stores data at a centralized database system .