What is your experience with database management systems?

My experience with database management systems includes:

• Using relational DBMSs such as PostgreSQL and MySQL for storing and retrieving data using SQL queries.
• Working with ORM libraries in Python, such as SQLAlchemy or Django ORM, which simplify interaction with the database through objects.
• Optimizing queries and indexes to improve performance.
• Using transactions to ensure data integrity.
• In some projects, I have used NoSQL databases, such as MongoDB, for storing unstructured data.

Example of connecting to a PostgreSQL database using psycopg2:

import psycopg2

conn = psycopg2.connect(
    dbname="testdb",
    user="user",
    password="password",
    host="localhost"
)
cur = conn.cursor()
cur.execute("SELECT * FROM users WHERE id = %s", (1,))
user = cur.fetchone()
print(user)
cur.close()
conn.close()