here are the top 50 MySQL interview questions for fresher-level candidates along with their answers:
Basic Concepts:
- What is MySQL?
- MySQL is an open-source relational database management system (RDBMS) that uses Structured Query Language (SQL).
- What is a Database Management System (DBMS)?
- A DBMS is software that manages databases, providing functionalities for storing, organizing, retrieving, and manipulating data.
- Differentiate between MySQL and SQL.
- MySQL is a specific implementation of a DBMS, while SQL (Structured Query Language) is a language used to interact with databases. MySQL uses SQL as its query language.
- What is a table in MySQL?
- A table in MySQL is a structured collection of data organized into rows and columns.
- Define a database schema.
- A database schema is a blueprint that defines the structure, relationships, and constraints of the data stored in a database.
- Explain normalization and denormalization.
- Normalization is the process of organizing data in a database to reduce redundancy and improve data integrity. Denormalization involves adding redundancy to a database to improve performance by avoiding costly joins.
- What is a primary key?
- A primary key is a unique identifier for each record in a table. It ensures that each row in the table can be uniquely identified.
- Describe foreign keys.
- A foreign key is a field or a combination of fields in one table that refers to the primary key in another table. It establishes a relationship between the two tables.
- What is a constraint in MySQL?
- A constraint is a rule that limits the values that can be placed in a column of a table. Common constraints include PRIMARY KEY, FOREIGN KEY, UNIQUE, NOT NULL, etc.
- Define indexing.
- Indexing is the process of creating an index on a table column to improve the speed of data retrieval operations such as SELECT queries.