What types of databases exist? (With essential components)

By Indeed Editorial Team

Published 8 June 2022

The Indeed Editorial Team comprises a diverse and talented team of writers, researchers and subject matter experts equipped with Indeed's data and insights to deliver useful tips to help guide your career journey.

A database is a collection of related files organised logically within a computer. The systematic organisation of raw facts and figures helps users quickly access and manipulate data. Using technology can positively change the way individuals and businesses collect, manipulate and monetise data. In this article, we discuss what types of databases exist and explore the common data management systems and query languages in the market.

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What types of databases exist?

Discovering what types of databases exist can help you choose the right one for you. The best approach when selecting a programme is first to understand your data needs. Consider factors like the size of data, the complexity of the system and the ease of use. It's also essential to factor in the organisation's size and the number of users that can simultaneously access the system. An effective database is easy to access, fits your data needs and is within your price range. The following are the most common types of databases:

Open-source

This type of database is free to use. You can download, instal and start using the application for free without buying the programme or paying a subscription fee. Open-source applications allow users to see the source code of the database and make changes.

Centralised

A centralised database keeps data in a single location. Users from remote areas can access data using several computer applications. A centralised type has an authentication system that allows only legitimate users to access the data. The centralised format enables the business to maintain uniformity and data standards throughout the organisation. Since users receive data from a central point, they can deduce the accepted quality within the organisation. The central control of data is cost-effective because businesses need fewer resources to store and manage data.

Object-Oriented Database (OODB)

This type of database presents data as classes and objects. The database uses the object-oriented database model approach that combines this model with relational model features. They're beneficial because objects can remain in persistent storage forever. Examples of Object-oriented databases include Cache, Db4o, ConceptBase and ObjectStore.

Cloud

This is an Internet-based database service that takes advantage of cloud computing technology. The developer or the user can create, deploy and access the system online. Users can self-manage, use the autonomous category or hire someone to run the database for them. It's beneficial to users because it's cost-effective, flexible to access and easy to use.

Relational

This type of database keeps data in a structured format of rows and columns within a table. The relational approach places data in pre-defined categories within the tables. Values relate to each other via columns and rows. It indexes the data to make it easier for queries to retrieve information.

Enterprise

Enterprise databases are suitable for large organisations that store and manage large volumes of data. This type allows users to run parallel queries without interfering with the system. Large organisations can use this application because it allows simultaneous access to the database.

Distributed

A distributed database is unique because it spreads data across multiple systems in the organisation. When using the distributed database, a user connects the different systems using communication links. Distributed types are preferable for users with a preference for speed and reliability in a database programme.

You can classify distributed databases into two categories. You can run the homogeneous database from the same device housing the operating system, application processes and hardware devices. You can execute the heterogeneous database from a separate operating system and use different hardware devices. Apache Cassandra and Ignite are the most common types in this category.

NoSQL

The Non-SQL database is a non-relational structure that stores data in many formats. Non-SQL provides a mechanism for storing data in several formats, for instance, in relational and non-relational table formats. The lack of structure allows the database to store and quickly process large data. NoSQL contains features like flexible schemas and horizontal scaling that makes it attractive to software developers. Some common examples of NoSQL types are MongoDB and InfoGrid.

Hierarchical

This type of database resembles a family tree. The database adopts a parent-children relationship format of storing data. The parent can have multiple children, but the child can have only one parent. It organises data in a hierarchy of directories where the top directory can have sub-categories that can have subdirectories. The hierarchical collection of data is good for storing nested data. This storage format helps users to access and manipulate data quickly.

Operational

An operational database allows users to change data in real-time. Businesses mostly use it in data warehousing. It allows users to add, remove or edit data at all times without waiting for batch processing.

Essential components of a database

While there are many types of databases on the market today, their components are similar in design and functionality. Below are the five essential components of databases:

Hardware

The hardware devices are the physical components of the database. They offer an interface between the user and the database software. Examples of hardware components are hard drives, computer peripherals and servers.

Data

Data refers to unorganised facts that you can process to present meaningful information to users. Raw data may comprise facts, numbers, images, figures, perceptions and observations. The data type usually dictates the organisation of data in a database.

Query language

A database requires at least one query language and a query dialect to function. A query access language enables users to interact with the database. It provides a mechanism for inserting and retrieving data. Today's common query languages are MongoDB Query Language (MQL) and structured query language (SQL). We can categorise query languages according to specific tasks they perform. For example, Data Control Language (DCL) deals with permissions, while Data Definition Language (DDL) defines database schemas.

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Procedures

Procedures refer to instructions issued by the database management system software. They guide the user on how to use the database. The procedures can range from instructions on logging in and out of the database, backup instructions and steps to generate reports.

Software

Software refers to a set of instructions used to run a computer application. Database software refers to programmes used to control the database. The database management system software enables users to interact with data. The software allows multiple users to access data without compromising its integrity.

Types of database languages and their uses

A database provides practical ways for individuals and companies to store and manage data. Developers use various programming languages to create and control database software that perfectly organises data. The languages are critical for the optimal performance of data management systems. The following are examples of languages used in database management:

Data definition language (DDL)

The language provides the structure for data organisation. It's used to create tables, columns and files. DDL can also change the name of existing databases. Data definition language statements create, alter, drop or rename existing objects in a database.

Data control language (DCL)

The language performs the function of controlling access to data. It gives or denies users permission to access the system. Developers use the language to grant, upgrade or revoke privileges of users within the system.

Data manipulation language (DML)

This language provides instructions that handle user queries. The language inserts, retrieves and updates data functions. Examples of DML commands include 'UPDATE', 'INSERT', 'SELECT' and 'DELETE'.

Transaction control language (TCL)

The transaction control language gives transaction instructions. The TCL groups related tasks into executable tasks. A transaction can only happen if all the tasks have succeeded. The TCL commands can restore a transaction if one task fails until it successfully completes all the tasks.

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Types of database management systems

The following are the database management systems:

Document database management systems (DoDBMS)

You can use this database management system for data organised in JSON-like structures. The DoDBM system is preferable for data with little or no relationship structures. Query language powers the system, like the MongoDB query language for operation.

Columnar database management systems (CDBMS)

This database management system specifically manages databases that store data in columns. The CDBMS format ignores any query that isn't column based. Apache HBase and Apache Cassandra are examples of columnar database applications that CDBMS manages.

Relational database management systems

The management system helps users to have read/write rights and generate specific reports. It enables users to present queries. The relational database management system is easy-to-use and is the most used management system in the market today.

Please note that none of the companies mentioned in this article are affiliated with Indeed.

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