(07) flask is OK if you have a hand -- flask Sqlalchemy

zero 、 Preface

This article , Elaborate on Flask in Database ORM Use

install

Use it directly pip install flask-sqlalchemy that will do

Use

initialization

Use ORM So that we don't have to write complicated SQL sentence

Database we use Python Self contained sqlite3 This does not require installation .

establish exts.py file , Write the following ：

from flask_sqlalchemy import SQLAlchemy
db = SQLAlchemy()

The code above means ： Create a SQLAlchemy object

establish models.py file , Write the following ：

from exts import db

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

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

The code above means ： Create a user model , In terms of our operation

Finally create app.py file , Write the following ：

from flask import Flask, jsonify
from exts import db
from models import User

app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = "sqlite:///foo.db"
db.init_app(app)

The code above means ： Combine our database with flask_app Binding .
The address of the database is ： In the current directory foo.db file

thus , The initial operation of the database has been completed .

Smart little buddy is about to ask , Why not exts.py and app.py Merged ？
answer ： If after the merger , that models.py Will quote SQLAlchemy object , and app.py And from models.py I quote User object , This will cause a circular reference problem .

Additions and deletions

@app.route('/create_table')
def create_table():
    db.create_all()
    return f" The database has been created successfully "

@app.route('/create/<name>')
def create(name):
    user = User(username=name)
    db.session.add(user)
    db.session.commit()
    return f" user {
      name} Created successfully "

@app.route('/query/all')
def query_all():
    users = User.query.all()
    data = {
    "all user": str(users)}
    return jsonify(data)

@app.route('/query_by/<name>')
def query_by_name(name):
    user = User.query.filter_by(username=name).first()
    data = {
    "user": str(user)}
    return jsonify(data)

@app.route('/delete_by/<name>')
def delete_by_name(name):
    user = User.query.filter_by(username=name).first()
    db.session.delete(user)
    db.session.commit()
    return " user ： Delete successful "

• First you need to visit create_table To create a database
• And then you can go through create/xiaobing Create a small soldier user
• adopt query_all Query all users
• adopt delete_by/xiaobing Delete the soldier user
  

Extended literature

• 【 Use other databases as Flask database 】