Database CRUD & Flask-Migrate

🐍 FlaskLesson 8Intermediate

Flask-Migrate handles database schema transitions using Alembic, while SQLAlchemy enables you to perform standard CRUD operations using session execution blocks.

1 Performing CRUD Operations

Python — CRUD Actions

# Create new record
new_user = User(username="balaji", email="b@test.com")
db.session.add(new_user)
db.session.commit()

# Read query lookup
user = User.query.filter_by(username="balaji").first()

# Update record
user.email = "new_email@test.com"
db.session.commit()

# Delete record
db.session.delete(user)
db.session.commit()

2 Database Migrations Setup

Shell — Terminal Commands

# Initialize migrations folder
flask db init

# Generate migration script file
flask db migrate -m "Initial migration"

# Apply migrations to database
flask db upgrade

3 Code Challenge

Challenge: Write a database initialization script or route that adds 10 dummy posts to the database using a bulk insertion list, committing them at the end.