Flask-SQLalchemy

Flask-SQLAlchemy is an extension for Flask that adds support for SQLAlchemy to your application.

a quick example

from flask import Flask
from flask_sqlalchemy import SQLAlchemy

app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:////tmp/test.db'
db = SQLAlchemy(app)


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

    def __init__(self, username, email):
        self.username = username
        self.email = email

    def __repr__(self):
        return '<User %r>' % self.username

@app.route('/data', methods=['GET', ])
def get_data():
    # ...
    return data

Select, Insert, Delete

Querying Records

• Select

  # Select the first
  User.query.first()
  User.query.get(1)   # According to primary key
  
  # Select all
  User.query.all()
  
  # Get the number of data quantity
  User.query.count()
  
  # Get the data with id 4
  User.query.filter_by(id=4).all()
  User.query.filter(User.id == 4).all()
  
  # startwith/endwith
  User.query.filter(User.name.startswith('xxx')).all()
  User.query.filter(User.name.endswith('xxx')).all()
  
  # contain
  User.query.filter(User.name.contains("n")).all()
  User.query.filter(User.name.like("%n%g")).all()
  User.query.filter(User.id.in_([1, 3, 5, 7, 9])).all()
  
  # Intersection condition
  from sqlalchemy import and_
  User.query.filter(and_(User.name == 'small', User.age = 18)).all()
  
  # Union condition
  from sqlalchemy import or_
  User.query.filter(or_(User.name == 'small', User.age = 18)).all()
  
  # Not contain
  from sqlalchemy import not_
  User.query.filter(not_(User.name == 'small')).all()
  
  # order (Default ascending)
  User.query.order_by(User.age, User.id.desc()).limit(5).all()
  
  # Paging query
  """
  pn.items: The amount of data retrieved
  pn.page : The current page
  pn.pages: The amount of pages
  """
  pn = User.query.paginate(page, items)

References

• Official Website Reference