Written By: Saniya Kalamkar
Understanding databases, something that is present everywhere, is a good topic to understand. Databases are organized collections of information (data) that are stored electronically and can be easily accessed and changed. They are used in every industry and affect our lives on a massive scale. For example, databases allow users to shop online at stores or restaurants, while streaming services, like Netflix rely on databases to showcase movie and TV options and to make recommendations to users. Weather apps also make good use of databases, as they come up with predictions from data stored in databases. Even a simple website with a login page would use a database.
Now that we have established the ubiquity of databases, how do these important databases work? Databases are managed by a database management system, or DBMS. Databases are also typically modeled in rows and columns in tables in which data is stored. A database for an online clothing store for example, may contain information or product type, the pricing of the product, and the user’s account information in a table. Queries are requests to a database or action on data. For example queries could combine data from tables, add data to a database, or even perform calculations. There are also many different types of databases that are all designed for different purposes.
Common Types of Databases
1. Relational Databases
Relational databases are databases in which data is stored in rows and columns of related tables. It is thought to be the most mature of the databases and is known for its reliability. Data can be organized into tables based on common data. SQL is the query language that is most often used in relational databases. Examples of relational databases include mySQL and Microsoft SQL Server.
2. Hierarchical Databases
A hierarchical database allows for data to be categorized in different levels, creating a hierarchy. It is also sometimes thought of as a parent-child model, in which parents are at a higher level than the children. However, children in the model cannot have more than one parent. Hierarchical databases are often used in high performance applications. Examples of hierarchical databases include IBM Information Management System and Windows Registry.
3. Cloud Databases
A cloud database is any database that has the added benefit of running on the cloud. They often require low maintenance. Examples of cloud databases include Microsoft Azure SQL Database, and Amazon Relational Database Service.
4. Object-Oriented Databases
An object-oriented database is based on object-oriented programming, and in which both data and its attributes are stored as objects. They are usually used with object-oriented programming languages such as Java or C#. Examples of object-oriented databases include Wakanda and ObjectStore.
5. NoSQL Databases
NoSQL databases are often referred to as non-relational databases and allow for data to be unstructured, while still allowing data to be stored and changed. An advantage of NoSQL databases is that the databases can be changed easily, with little impact on applications using the database. Examples of NoSQL databases include Apache Cassandra and MongoDB.