--- title: "SHRESHTHA KUMAR GUPTA (@shreshtxa) | Hashnode" description: "I love solving problems and talking about tech :). Read the latest articles by SHRESHTHA KUMAR GUPTA on Hashnode." url: "https://hashnode.com/@shreshtxa" --- @shreshtxa # SHRESHTHA KUMAR GUPTA @shreshtxa · Gurugram,India · Joined July 2023 I love solving problems and talking about tech :) ### [What is NCMC ?](https://techdosage.hashnode.dev/what-is-ncmc?utm_source=hashnode&utm_medium=feed) The Morning Rush, My Metro Card, and a Deep Dive into NFC/NCMC! This morning, when I was rushing late for the office (story of my life!), I reached the metro station only to realize my card wasn't recharged. Thankfully, I have one of the new Airtel N... 3 min read · [techdosage.hashnode.dev](https://techdosage.hashnode.dev/what-is-ncmc?utm_source=hashnode&utm_medium=feed) [Jul 23, 2025](https://hashnode.com/posts/what-is-ncmc/6880f497d52f0c98ac43ec48) ### [ACID Transactions in Databases: A Q&A Guide](https://shreshtxa.hashnode.dev/acid-transactions-in-databases-a-qanda-guide?utm_source=hashnode&utm_medium=feed) ❓ What exactly is a transaction in a database? A transaction is a sequence of one or more operations (such as inserts, updates, or deletes) that are executed as a single logical unit. The central idea is that all these operations must either complete... 4 min read · [shreshtxa.hashnode.dev](https://shreshtxa.hashnode.dev/acid-transactions-in-databases-a-qanda-guide?utm_source=hashnode&utm_medium=feed) [Apr 15, 2025](https://hashnode.com/posts/acid-transactions-in-databases-a-qanda-guide/67fe3e25f393cf6519057ca1) ### [System Design](https://shreshtxa.hashnode.dev/system-design?utm_source=hashnode&utm_medium=feed) 1\. What is the fundamental difference in data modeling between SQL and NoSQL databases? SQL: Utilizes a relational data model with structured tables, rows, and columns. Relationships are established using foreign keys, and data integrity is maintain... 3 min read · [shreshtxa.hashnode.dev](https://shreshtxa.hashnode.dev/system-design?utm_source=hashnode&utm_medium=feed) [Apr 14, 2025](https://hashnode.com/posts/system-design/67fd0100759fa6b6ce6ac57a) ### [Computer Networks](https://shreshtxa.hashnode.dev/computer-networks?utm_source=hashnode&utm_medium=feed) Which layer of the OSI model is responsible for end-to-end communication and provides services like encryption and decryption? — A. Transport Layer — B. Presentation Layer — C. Application Layer — D. Session Layer — Correct Answer: B What is the pur... 2 min read · [shreshtxa.hashnode.dev](https://shreshtxa.hashnode.dev/computer-networks?utm_source=hashnode&utm_medium=feed) [Apr 14, 2025](https://hashnode.com/posts/computer-networks/67fcb6c6954deff3cd1e7c52) ### [DBMS Important Questions](https://shreshtxa.hashnode.dev/dbms-important-questions?utm_source=hashnode&utm_medium=feed) What is the difference between primary key and unique constraints?The primary key cannot have NULL value, the unique constraints can have NULL values. There is only one primary key in a table, but there can be multiple unique constrains. What are the... 13 min read · [shreshtxa.hashnode.dev](https://shreshtxa.hashnode.dev/dbms-important-questions?utm_source=hashnode&utm_medium=feed) [Aug 11, 2024](https://hashnode.com/posts/dbms-important-questions/66b81c28e17e3f6d1dbae161)