flask-sqlalchemy的基本使用

flask-sqlalchemy

1 .配置应用和基本使用

和sqlalchemy一样，先定义好数据库配置和db_url。然后在app的config加入SQLALCHEMY_DATABASE_URI等于配置好的db_url。在初始化db对象即可。

from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from settings import DATABASES

app = Flask(__name__)

DB_URL = 'mysql+pymysql://{USERNAME}:{PASSWORD}@{HOST}:{PORT}/{DATABASE}'.format(**DATABASES)

app.config['SQLALCHEMY_DATABASE_URI'] = DB_URL
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False

db = SQLAlchemy(app)

class User(db.Model):
    __tablename__ = 'user'
    id = db.Column(db.Integer, primary_key=True, autoincrement=True)
    name = db.Column(db.String(50))

class Article(db.Model):
    __tablename__ = 'article'
    id = db.Column(db.Integer, primary_key=True, autoincrement=True)
    name = db.Column(db.String(50))
    user_id = db.Column(db.Integer, db.ForeignKey('user.id'))

    user = db.relationship('User', backref=db.backref(__tablename__, lazy='dynamic'))

@app.route('/')
def hello_world():
    return 'hello world'

db.create_all()

# 增加数据
user = User(name='ivy')
article = Article(name='title')
article.user = user

db.session.add(article)
db.session.commit()

# 查询数据
first_user = user = db.session.query(User).first()
print(first_user.name)
print(first_user.article.first().name)

if __name__ == '__main__':
    app.run()

2 .配合alembic

• alembic.ini的文件的配置不变
• 在alembic的文件夹的env.py中, 将生成的db对象文件模块导入, app.db.Model.metadata