NoSQL interview questions

Following is a list of the differences between NoSQL and RDBMS: –

• In terms of data format, NoSQL does not follow any order for its data format. Whereas, RDBMS is more organized and structured when it comes to the format of its data.
• When it comes to scalability, NoSQL is more very good and more scalable. Whereas, RDBMS is average and less scalable than NoSQL.
• For querying of data, NoSQL is limited in terms of querying because there is no join clause present in NoSQL. Whereas, querying can be used in RDBMS as it uses the structured query language.
• The difference in the storage mechanism of NoSQL and RDBMS is that, NoSQL uses key value pair, documents, column storage, etc. for storage. Whereas, RDBMS uses various tables for storing data and relationships.

The NoSQL database management system is a distributed key-value database. It is designed so that it can provide highly reliable and scalable data. It can make the data storage available across all the configurable set of systems which functions as storage nodes. In this database system, data is stored as key-value pairs. This data is written to a particular storage node. These databases provide a mechanism for the storage and retrieval of data which is composed in a way other than the tabular method which was used in the relational databases.

• Using NoSQL, we can store the large amount of structured, semi-structured, and unstructured data.
• It supports agile sprint, quick iteration, and frequent code pushes.
• It uses object-oriented programming which is frequent and is also easy to use.
• It is more efficient. It has a scale-out architecture. It is cheap instead of being expensive. It has a monolithic architecture. It can be easily accessed.

Pros of using graph database:

• These are tailor-made for the networking applications. A social network is a good example of this.
• They can also be perfect for an object-oriented programming system.

Cons of using graph database:

• Since the degree of interconnection between nodes is high in graph database, so it is not suitable for network partitioning.
• Also, graph databases don’t scale out well in NoSQL databases.

1. Key value store- it is a simple data storage key system which uses keys to access different values.
2. Column family store- it is a sparse matrix system. It uses columns and rows as keys.
3. Graph store- it is used in case of relationships-intensive problems.
4. Document stores- it is used for storing hierarchical data structures directly in the database.

• Consistency- in this, all the nodes see the same data at the same time.
• Availability- it gives us a guarantee that there will be a response for every request made to the system about whether it was successful or not.
• Partition tolerance- it is the quality of NoSQL database management system which states that the system will work even if a part of the system has failed or is not working.

A distributed database system might provide only 2 of the 3 above qualities.