Relational vs Non-Relational Databases

A Database is a collection of information that is stored systematically to make easy use to access, manage, and update the data. It contains the data records, files, and sales transaction details of customers. In 1960, the database evolved from the network database to today’s SQL, NoSQL, and cloud databases. The database manager allows the user to control read and write access, analyze the usage, and generate reports. 

The database is used to store data and provide tools to search for specific records in a set of data. It can solve issues where many users want to access the same entries of data. The database maintains the access rights of the user which restricts the reading and writing of the data. The database is used for multiple domains such as business, education, Organizations, etc. where there is a need to store a massive amount of data. There are different types of databases. They are as follows:

• Centralized database
• Commercial database
• Cloud database
• Distributed database
• End-user database
• Graph database
• Object-oriented database
• Personal database
• Relational database
• Non-relational database

Want to become an Oracle-certified professional? Visit here to learn about Oracle DBA Online Training

Relational vs Non-relational Databases - What is the Difference?  

In this article, we will learn the following topics:

• What is a Relational database?
• What is a Non-relational Database
• Difference between Relational and Non-relational database

Before going to learn the differences between Relational and Non-relational databases, let’s see what they are?

What is a Relational database?

The relational database is structured data based on the relational model of data that stores data using tables, rows, and columns.  Columns represent the data stores and sort a specific type of information, a row represents a record with defined data points, and the table consists of these columns and rows. The table stores the data records of one entity or an object at a time.

The relationship between tables and field types is called a schema, and it must be defined clearly. When additional details are required, or to be associated with the record from one table to another, then we need to call relationships. The relationships are established through foreign keys and primary keys.

Various Relational database systems

The various relational database systems that are most popularly used are as follows:

• Microsoft SQL Server
• Oracle
• MySQL
• PostgreSQL
• Microsoft Azure SQL
• IBM DB2

Related Article: Oracle DBA Tutorial

Advantages of Relational database

The following are the advantages of a relational database:

• Relation database work with structured data
• It supports ACID(Atomicity, Consistency, Isolation, Durability) set of properties that ensure reliable database transactions
• It provides an in-built data integration and a broad ecosystem
• There is no limit in indexing and offers robust SQL
• It can handle complex queries, transactions, and analysis of data

Disadvantages of Relational database

The following are the disadvantages of the relational database:

• Data is normalized, lots of joins that might affect the speed
• Lots of issues while working with semi-structured data
• A relational database cannot store complex images, designs, multimedia products, and numbers.
• highly expensive with maintenance and new servers

What is the Non-relational Database?

The non-relational database is a document-oriented database rather than using tables; the documents enable to store the unstructured data in a single document. This document includes customer details, orders, favorites, etc. It deals with semi-structured data and looks like a folder with files rather than a table. It can process any type of data without modifying the architecture. As a result, creating and maintaining a non-relational database is much faster and cheaper.

Various Non-relational database systems

The various Non-relational database systems that are most popularly used and depending on the types of Non-relational databases are as follows:

• Column Store- Apache HBase, Cassandra
• Key-Value Store- Redis, Amazon DynamoDB
• Graph- neo4J, OrientDB, Titan
• Document-oriented database- MongoDB, Couchbase

Read these latest Oracle DBA interview questions that help you grab high-paying jobs!

Advantages of Non-relational database

The following are the advantages of a Non-relational database:

• Object-oriented programming makes it easy to use and flexible
• It can deal with large volumes of structured, unstructured, and semi-structured data
• It provides high availability
• No schema required
• Provides efficiency, scale-out with a monolithic architecture

Disadvantages of Non-relational database

The following are the advantages of the Non-relational database:

• The non-relational database is still growing, and many features are yet to be implemented
• It requires some technical skills to install and maintain
• As it is open-source, it will provide less support
• Does not have in-built data integrity
• Weak or Eventual consistency BASE (Basically Available, Soft state, Eventually consistent) 
• Differences between Relational and Non-relational database

Now, Let’s see the differences between Relational and Non-relational databases. 

What is the Difference Between Relational and Non-Relational Database?

Relational	Non-relational
The relational database is a structured database.	The non-relational database is a document-oriented database.
It has a predefined schema.	It uses a dynamic schema for the unstructured database.
The relational database is vertically scalable.	The non-relational database is horizontally scalable.
It is not suitable for hierarchical data storage.	It is ideal for hierarchical data storage as it supports the key-value method.
The query language is Structured Query Language(SQL).	No declarative query language.
It is used when data validity is important.	It is used when it is important to have fast data than correct data.
It supports the ACID(Atomicity, Consistency, Isolation, Durability) set of properties.	It supports the BASE(Basically Available, Soft state, Eventually consistent) model.
It is configured for durable consistency.	It depends on the Database management system(DBMS) that offers strong consistency such as MongoDB, and some other that offers eventual consistency such as Cassandra.
It offers features like cross-platform, secure, and free.	It offers features like High performance, flexible tool, and ease to use.
It is best used for solving the ACID set of problems.	It is best used for solving data availability problems.
Examples: Postgre, MySQL, Oracle, etc	Examples: MongoDB, Redis, Cassandra, etc.

Conclusion

The traditional relational database is good at securing the data and making complex queries to acquire information. Companies that are structured are likely to use a relational database. The non-relational database is excellent at storing a massive amount of data providing more flexibility and scalability. Companies that are experiencing growth are likely to use a non-relational database. 

However, few companies are likely to use the combination of both relational and non-relational databases to meet their business requirements.