A database is an organized set of structured information or data, usually stored electronically in a computer system. A database is usually controlled by a database management system (DBMS). Together, the data and the DBMS and related applications are called a database system, which is often shortened simply to the concept of a database.
There are many different types of databases. The best database for a particular organization depends on how the organization intends to use the data.
Relational databases. Relational databases became dominant in the 1980s. Items in a relational database are organized as a set of tables with columns and rows. Relational database technology provides the most efficient and flexible way to access structured information.
Object-oriented databases. Information in an object-oriented database is represented as objects, as in object-oriented programming.
Distributed databases. A distributed database consists of two or more files located at different sites. The database can be stored on multiple computers, located in the same physical location, or scattered across different networks.
Data warehouses. A centralized data warehouse, a data warehouse is a type of database specifically designed for rapid querying and analysis.
NoSQL databases. NoSQL, or non-relational database, allows you to store and process unstructured and semi-structured data (as opposed to a relational database, which defines how all data inserted into a database must be composed). NoSQL databases became popular as Web applications became more pervasive and complex.
Graph databases. A graph database stores data in terms of entities and relationships between entities.
OLTP databases. An OLTP database is a fast, analytical database designed for a large number of multi-user transactions.
These are just a few of the several dozen types of databases in use today. Other, less common databases are designed for very specific scientific, financial, or other functions. In addition to the different types of databases, changes in technology development approaches and significant advances such as cloud technology and automation are pushing databases in entirely new directions. Some of the latest databases include:
Open Source Databases (OpenSource). An OpenSource database system is an open source system; such databases can be SQL or NoSQL databases.
Cloud Databases. A cloud database is a set of structured or unstructured data that is stored on a private, public, or hybrid cloud computing platform. There are two types of cloud database models: traditional and Database as a Service (DBaaS). In the case of DBaaS, the administrative tasks and maintenance are performed by the service provider.
Multi-model database. Multi-model databases combine different types of database models into a single integrated server part. This means that they can support different types of data.
Document Database / JSON. Document databases, designed to store, retrieve, and manage document-oriented information, are a modern way to store data in JSON format rather than rows and columns.
Standalone databases. The newest and most revolutionary type of database, autonomous databases (also known as offline databases) are cloud-based and use machine learning to automate database configuration, security, backups, updates, and other routine management tasks traditionally performed by database administrators.