A database is a collection of electronic information (data) stored on a web server. A database generally contains multiple ‘tables’ that contain relational data. If you have ever used Microsoft Excel, the data tends to be set up in a rows and columns type structure, much like Excel, and referenced between different tables via one column that contains a reference number. This makes processing and data querying efficient.
A database is normally controlled by a database management system or DBMS. Together the data and the DBMS along with the applications that are associated with them are referred to as a database system, and often shortened just to database.
Types of Databases:
- 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 in the form of objects, as in object-oriented programming.
- Distributed databases. A distributed database consists of two or more files located in different sites. The database may be stored on multiple computers, located in the same physical location, or scattered over different networks.
- Data warehouses. A central repository for data, a data warehouse is a type of database specifically designed for fast query and analysis.
- NoSQL databases. A NoSQL, or non-relational database, allows unstructured and semistructured data to be stored and manipulated (in contrast to a relational database, which defines how all data inserted into the database must be composed). NoSQL databases grew popular as web applications became more common and more complex.
- Graph databases. A graph database stores data in terms of entities and the relationships between entities.
- OLTP databases. An OLTP database is a speedy, analytic database designed for large numbers of transactions performed by multiple users.
- Open source databases. An open source database system is one whose source code is open source; such databases could be SQL or NoSQL databases.
- Cloud databases. A cloud database is a collection of data, either structured or unstructured, that resides on a private, public, or hybrid cloud computing platform. There are two types of cloud database models: traditional and database as a service (DBaaS). With DBaaS, administrative tasks and maintenance are performed by a service provider.
- Multi-model database. Multi-model databases combine different types of database models into a single, integrated back end. This means they can accommodate various data types.
- Document/JSON database. Designed for storing, retrieving, and managing document-oriented information, document databases are a modern way to store data in JSON format rather than rows and columns.
- Self-driving databases. The newest and most groundbreaking type of database, self-driving databases (also known as autonomous databases) are cloud-based and use machine learning to automate database tuning, security, backups, updates, and other routine management tasks traditionally performed by database administrators.
Query languages can be used to then retrieve information from a database. SQL or Structured Query Language, one of the most popular, is a language that can be used to retrieve, add or update database information.