SQLAlchemy is a powerful Python SQL toolkit and Object-Relational Mapper (ORM) that gives developers full control over SQL and database interactions with both high-level and low-level access.

Why Use SQLAlchemy?
Works with multiple databases (SQLite, MySQL, PostgreSQL, etc.)
Clean separation between schema and business logic
ORM + Core (SQL Expression Language)
Helps avoid raw SQL and SQL injection risks
Flexible, scalable, and production-ready

Installation
bash
pip install SQLAlchemy


Basic Setup
python
from sqlalchemy import create_engine

engine = create_engine('sqlite:///example.db', echo=True)


Defining Models (ORM)
python
from sqlalchemy import Column, Integer, String
from sqlalchemy.ext.declarative import declarative_base

Base = declarative_base()

class User(Base):
_tablename_ = 'users'
id = Column(Integer, primary_key=True)
name = Column(String)
age = Column(Integer)


Creating Tables
python
Base.metadata.create_all(engine)


Working with Sessions
python
from sqlalchemy.orm import sessionmaker

Session = sessionmaker(bind=engine)
session = Session()
new_user = User(name=Alice, age=25)
session.add(new_user)
session.commit()


Querying Data
python
users = session.query(User).filter_by(name=Alice).all()
for user in users:
print(user.name, user.age)


Real-World Use Cases
Backend of web apps (Flask, FastAPI, Django)
Scalable enterprise apps
Data migration & analytics tools
Database-heavy services

Summary
Ideal For: Developers needing robust database interaction
Strength: Flexible ORM & raw SQL support
Bonus: Works well with frameworks like Flask and FastAPI