Python Interview Questions for Database Integration

Database integration using Python is a common task in software development. Python offers several libraries and frameworks for working with databases. Here are some common interview questions for database integration using python:

Question 1: What is Python’s DB-API?

Answer: Python’s DB-API is a standard API that allows Python code to interact with relational databases. It provides a set of common methods to connect to a database, execute queries, fetch results, and handle transactions, among other operations.

Question 2: What are some popular Python libraries for database integration?

Answer: Some popular Python libraries for database integration are SQLite3, MySQLdb, psycopg2 for PostgreSQL, and SQLAlchemy as an Object Relational Mapper (ORM).

Question 3: How do you connect to a MySQL database using Python?

Answer: You can connect to a MySQL database using Python by installing the mysql-connector-python package and using its connect method to create a connection object.

Python

import mysql.connector

conn = mysql.connector.connect(
    host='localhost',
    user='username',
    password='password',
    database='mydatabase'
)

Question 4: How do you execute SQL queries in Python?

Answer: SQL queries can be executed in Python by using the cursor.execute() method after creating a cursor object from the connection object.

Python

cursor = conn.cursor()
cursor.execute("SELECT * FROM table_name")

Question 5: How do you fetch data after executing a SQL query?

Answer: Data can be fetched using methods like cursor.fetchone() for a single row or cursor.fetchall() for all rows.

Question 6: What is SQLAlchemy?

Answer: SQLAlchemy is an Object-Relational Mapping (ORM) library for Python. It allows you to interact with your database using Python classes and objects instead of writing raw SQL queries.

Question 7: How do you handle transactions in Python’s DB-API?

Answer: Transactions can be handled using the commit() and rollback() methods on the connection object.

Python

try:
    cursor.execute("SQL QUERY")
    conn.commit()
except:
    conn.rollback()

Question 8: How do you use parameters in SQL queries?

Answer: Parameters can be used in SQL queries to prevent SQL injection. You can use placeholders like %s in the query and pass the parameters as a tuple.

Python

cursor.execute("INSERT INTO table_name (col1, col2) VALUES (%s, %s)", (val1, val2))

Question 9: What are the differences between SQLite and MySQL in Python?

Answer: SQLite is a lightweight, serverless, and self-contained SQL database engine, suitable for small projects or embedded applications. MySQL, on the other hand, is a fully-featured, enterprise-level database with support for multi-user access, ACID compliance, and networking.