NoSQL stands for “Not Only SQL”, and it is a database model. Also, unlike Relational Database, it does not use tables to store data. There are various types of NoSQL databases that use different data models to store data. The major NoSQL types are document, key-value, wide-columns, and graphs.
NoSQL database performs better than a relational database and it is more scalable and can handle data efficiently. In this article, we will discuss everything important about the NoSQL database that you should know, especially if you want to work with it.
What is NoSQL?
When we say NoSQL database, we simply mean a non-relational database, which does not use a table-like structure to store data. Some developers also refer to NoSQL as “non-SQL” while many others refer to it as “Not Only SQL”. Nonetheless, all database developers agree on one concept that NoSQL databases are databases that do not follow relational table data structure to organize and manage data.
The NoSQL database can use the relationship between data to manage and organize records but the data would not be formatted like relational rows and columns. NoSQL also follows some relational tactics so it can also store relational data. Many developers find the relational data of NoSQL easier to manage than a relational database because NoSQL databases do not split or divide their data into multiple tables.
Types of SQL Databases
There are 4 common types of NoSQL databases
- Document Database
- Key-Value Database
- Wide Column Database
- Graph Database
1. Document Database
A NoSQL Document Database uses the JSON-like object to store data. The document contains the pairs of fields and values, where fields are the attributes and values are the actual data or record. Also, the value data can be of any data type such as string, numbers, boolean, array, or object.
NoSQL document databases contain a wide variety of data types and powerful & robust query languages, which make them a great choice for handling large volumes of data. MongoDB, which is one of the most popular NoSQL databases, works on the Document Database model.
2. Key-value Database
The key-value database uses key-value pairs to store data and its attribute. To retrieve the data from the database, we can use the data corresponding key.
In general, the true power and potential of a key-value database become evident when we want a large database where we do not want to use complex queries. DynamoDB and Redis NoSQL databases use the Key-value Database model.
3. Wide-Column Database
Wide-Column Database uses a table-like data structure to store its data. However, it is different from a relational database in the sense that it does not use rows and fixed columns but dynamic columns. In a wide-column database, it is not necessary that each row record has to follow the same column. This dynamic column approach of the wide-columns database gives it more flexibility over the relational databases.
Developers choose wide-column databases for those projects where they need to store a large amount of data and the query patterns are already predicted, IoT is the classical example of a wide-column database. Cassandra and HBase are two widely used wide-columns store databases.
4. Graph Databases
Like a normal Graph Data structure, a Graph Database uses the concept of nodes and edges to store data. Here the node represents the real-entity or data such as people things, and the edges represent the relation between the nodes or data. Machine learning and artificial intelligence models make use of Graph Database because it is very easy to traverse in this database and the relationship between the data can be easily represented. Neo4j and Janus Graph are the two most popular NoSQL Databases based on the graph database model.
Advantages and Disadvantages of NoSQL Databases
Like every technology, NoSQL has some merits and demerits. Let’s have a look at the advantages and disadvantages of NoSQL databases.
- NoSQL databases come with high scalability, and they can load data faster than a relational database.
- The cost of a NoSQL database is also low as compared to a relational database.
- NoSQL databases come with an auto replication feature; in case the database fails to fetch data, the auto replication uses the previous data.
- NoSQL only focuses on storing data and lacks certain database functionalities available in relational databases.
- Graphical Tools for NoSQL are not available in the market.
- In many NoSQL databases, the backup process is not consistent.
- NoSQL database generally has a large document size. The similar data in a relational database would occupy less space.
NoSQL is generally preferred by those businesses that only want to focus on data storage and do not want to spend much on a database. Also, many developers like this database because it can store unstructured data, which means developers do not need to define the database schema before storing data.
In the past few years, cloud computing also gained too much popularity amongst technical and non-technical users. Many NoSQL databases offer scalability, distributed data, and application resilient properties that make them a perfect database for cloud storage.
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