What is NoSQL Database

What is NoSQL Database?

NoSQL stands for not only SQL it provides a way to store and retrieve the data that is stored in tabular format as in relational databases. It is a complementary addition to SQL and Relational databases. These are flexible database management systems that provide the way to store and process both structured and semi-structured data which RDBMS tools cannot process.

Definition Of NoSQL Database

NoSQL database is used when working with large sets of distributed data. They are used in real-time web applications and their usage is increasing with time. A NoSQL database has a simple design, fine control over availability and simple horizontal scaling to clusters of machines. The operations of NoSQL are faster than relational databases due to the use of different data structures. The type of problem is a deciding factor for the suitability of the NoSQL database. The data structures used in NoSQL databases are more flexible than the tables used in relational databases. Availability, partition tolerance and speed are given more preference than consistency in many NoSQL stores. Most NoSQL stores do not follow the ACID (Atomicity, Consistency, Isolation, Durability) properties of transactions but some databases like Aerospike, Google Spanner, MarkLogic, OrientDB and Symas LMDB have made these properties as a center to their designs.

Difference between SQL database and NoSQL database

Features of NoSQL

Below are some of the important features of NoSQL which are as follows:

Dynamic schemas

NoSQL databases permit to insert the data without the predefined schema. Real-time application changes can be made easily without the need to worry about service interruptions. This makes development faster, more reliable and less time consuming for the database administrator.

Auto-sharding

Horizontal scaling is done in a NoSQL database i.e. servers are added instead of increasing the capacity of a single server. NoSQL databases provide auto-sharding feature i.e. it automatically spread data across a various number of servers. Application need not be aware of the composition of the server pool. A load of data and query are automatically balanced among the servers. If any server fails, then it is replaced quickly and transparently without disrupting the application.

Replication

NoSQL database allows automatic database replication. It is done to maintain availability in case of outages. Some sophisticated NoSQL databases provide automated recovery and are fully self- healing. To enable data localization and to withstand regional failures, it can distribute the database across multiple geographic regions. NoSQL does not require a separate application to implement replication.

Integrated Caching

NoSQL databases have integrated caching capability i.e. they keep frequently used data in system memory and remove the need for the separate caching layer.

Simple API

NoSQL offers interfaces that are easy to use for storing and querying data. APIs allow selection methods and low-level data manipulation. It uses no standard based query language.

Why should we Use NoSQL Database?

• Analytics: NoSQL database is suitable for doing analytical queries. Querying language used for atomic queries can also be used for analytical queries.
• Scale: NoSQL database is preferred because they are designed to scale. They are designed to easily scale out when they grow. Data is divided and balanced among multiple nodes in a cluster and by default, aggregate queries are divided.
• Redundancy: NoSQL database is designed while keeping redundancy in concern. NoSQL database is designed to handle hardware failure instead of treating them. The problem of hardware failure is handled during the time of development.
• Flexibility: There is huge flexibility in the way the data is stored and this increases the performance in the NoSQL database.
• Rapid Development: NoSQL database provides an easy way to change the way data is stored or change the queries that are running. Batch processing and simple refactoring are done to accomplish massive changes.

Types of NoSQL Database

There are four primary types of NoSQL database i.e. Key-value stores, Document databases, wide- column stores and graph stores.

1. Key- Value Stores: These databases work on a simple data model that has a pair of unique key and a value associated with it. These databases perform efficiently and show high scalability for caching in web applications and session management. They work with RAM, disk drives or solid state drives.
2. Document databases: These databases store semi-structured data and their descriptions in document format. They do not refer to master schema for creating and updating programs. Their usage has increased with the use of JavaScript and JSON (JavaScript Object Notation). These are used for mobile application data handling and content management.
3. Wide- column stores: These databases organize data in columns instead of rows. They can query large data sets faster than other conventional databases. These are used for catalogs, fraud detection, and recommendation engines.
4. Graph Stores: These databases organize data as nodes and edges that show connections between nodes. These are used where map relationships are needed like customer relationship or reservation systems management.

Advantages

• High scalability
• High availability
• Big data capability
• Easy replication
• Fast performance
• High flexibility

Disadvantages

• Narrow focus
• Open source
• Management challenge
• GUI not available
• Large document size

Conclusion

This article tells about the basics of NoSQL database which are used to store and retrieve large data sets or to handle big data. They were developed to overcome the limitations of Relational databases.

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