Flask-SQLAlchemy-Guide

Flask-SQLAlchemy Comprehensive Guide Repository

This repository provides a structured and detailed guide on using Flask-SQLAlchemy to manage models and interact with databases in Flask applications. The goal is to share knowledge about different attributes, column options, and best practices.


Project Structure

flask-sqlalchemy-guide/
├── README.md                # Project overview and introduction
├── setup/                    # Environment setup instructions
│   └── environment.md
├── models/                   # Guides on defining models
│   ├── basic-models.md       # Basic model creation
│   ├── column-attributes.md  # Column options and attributes
│   ├── relationships.md      # Defining relationships (One-to-Many, Many-to-Many)
│   └── validations.md        # Model constraints and validation
├── database/                 # Database creation and management
│   ├── creating-tables.md    # How to create tables
│   └── migrations.md         # Database migrations with Flask-Migrate
└── examples/                 # Practical examples and best practices
    ├── simple-app/           # Simple Flask app with SQLAlchemy
    └── advanced-features/    # Advanced configurations

1. Setting Up the Environment

Instructions to set up the environment:

  • Installing Flask-SQLAlchemy
  • Creating a virtual environment
  • Connecting to different databases

Example Configuration:

from flask import Flask
from flask_sqlalchemy import SQLAlchemy

app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///database.db'
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False

db = SQLAlchemy(app)

2. Defining Models

Basic structure of defining models and mapping them to tables.

Example:

class User(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(80), nullable=False)
    email = db.Column(db.String(120), unique=True, nullable=False)

Comprehensive list of column attributes:

  • Data Types: db.Integer, db.String, db.Float, db.Boolean, etc.
  • Common Options:
    • primary_key=True
    • nullable=False
    • unique=True
    • default=value

Example:

price = db.Column(db.Float, default=0.0, nullable=False)
created_at = db.Column(db.DateTime, default=db.func.now())

Guide on creating relationships between tables:

  • One-to-Many
  • Many-to-Many

Example:

class Post(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    user_id = db.Column(db.Integer, db.ForeignKey('user.id'))
    user = db.relationship('User', backref='posts')

How to apply model-level constraints and validation.


3. Database Management

Steps to create tables and manage the database lifecycle.

Creating Tables:

with app.app_context():
    db.create_all()

How to handle migrations using Flask-Migrate.


4. Examples and Best Practices

A minimal example of a Flask app with a User model.

Examples demonstrating advanced configurations such as:

  • Custom Query Methods
  • Database Indexing
  • Performance Optimization

How to Contribute

Feel free to open issues or submit pull requests to improve this guide.


License

MIT License

Visit original content creator repository
https://github.com/jaimin-bariya/Flask-SQLAlchemy-Guide

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