Features — SQL Technical Interview Questions & Answers

Features

Features

  • MySQL features you should actually name in a viva, not a marketing list: it is a relational database (tables + keys), it is free/open source for learning, it runs on Windows, Linux, and Mac, and InnoDB gives transactions (commit / rollback).
  • It talks over a network. Your PHP, Java, or Node app connects with a host, user, password, and database name. Many websites use this. That is the ‘client-server’ feature — the app is the client, mysqld is the server.
  • Useful extras: indexes to find a roll number fast, users and GRANT so a intern cannot DROP the whole college DB, and backups with mysqldump. InnoDB is the default engine for real tables. MyISAM is older and does not do proper transactions — don’t pick it for fees.
  • Trap: reciting twenty feature names with no example. Pick four: tables, SQL, InnoDB transactions, used by web apps. If they ask ‘open source’, say you can install it without buying a licence for practice.
  • On the example next to this theory: Features: create two demo rows, then SELECT qty >= 2 ordered. Say which labels come back.

Technical Interview Tip: Four features: tables, SQL, InnoDB transactions, web apps connect as clients.

Code Examples for Features

Features — sample query

-- Features
CREATE TABLE demo (
  id INTEGER PRIMARY KEY,
  label TEXT NOT NULL,
  qty INTEGER DEFAULT 0
);
INSERT INTO demo (id, label, qty) VALUES
  (1, 'alpha', 2),
  (2, 'beta', 5);
SELECT label, qty FROM demo WHERE qty >= 2 ORDER BY qty DESC;

Features: create two demo rows, then SELECT qty >= 2 ordered. Say which labels come back.

How to Explain Features to an Interviewer

Name four MySQL features.

Relational tables SQL queries InnoDB transactions Client-server (apps connect)

Why InnoDB?

Commit / rollback Good default for real tables