Relational or SQL Databases
- These are also called SQL databases.
- These are used to store structured data.
- Relational Databases stores data in rows and columns.
- Relational Databases can be accessed using SQL (Structured Query language), as the language for querying and maintaining the database.
- These support ACID (Atomicity, Consistency, Isolation, Durability) transactions, as the integrity of data is very important.
- Relational Databases are mainly used for OLTP (Online transaction processing), which includes business transactional processing using real-time data.
For example, Database to hold transactions from ATM.
Most popular Relational/SQL databases are:
- SQL Server
- Maria DB
- Aurora DB
Non-Relational or NoSQL Databases
- These types of databases are also called NoSQL databases OR “Not only SQL” databases.
- These databases store a large amount of unstructured data.
- These don’t use relational models and schema.
- These databases are designed to run on large clusters.
- Non-Relational Databases use JSON, XML, or Key-value pairs.
- These can be column-based, document-based, or graph-based.
- These also have a flexible schema, so it can be a row-based, column-based, or follow document approach.
- Most NoSQL databases support data replication, storing multiple copies of data across the cluster or data centers to ensure high availability and disaster recovery.
- Non-Relational Databases are used for BigData and real-time web applications, where a huge amount of data is being delivered.
Most popular Non-Relational/NoSQL Databases are:
- AWS DynamoDB