使用Flask_SQLAlchemy连接多个数据库

#!/usr/bin/env python
#-*- coding: utf-8 -*-


from flask import Flask
from flask_sqlalchemy import SQLAlchemy

app = Flask(__name__)

# 配置多个数据库连接
SQLALCHEMY_BINDS = {
    'users': 'sqlite:///users.db',
    'appmeta': 'sqlite:///appmeta.db'
}

app.config['SQLALCHEMY_DATABASE_URI'] =  'sqlite:///test.db' # 默认数据库引擎
app.config['SQLALCHEMY_BINDS'] = SQLALCHEMY_BINDS
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False

db = SQLAlchemy(app)


class News(db.Model):
    __tablename__ = 'news' # 未设置__bind_key__,则采用默认的数据库引擎

    id = db.Column(db.Integer, primary_key=True)
    news_title = db.Column(db.String(80), unique=True)
    news_content = db.Column(db.String(120), unique=True)

    def __init__(self, news_title, news_content):
        self.news_title = news_title
        self.news_content = news_content

    def __repr__(self):
        return '' % self.news_title

class User(db.Model):
    __bind_key__ = 'users' # 已设置__bind_key__,则采用设置的数据库引擎
    __tablename__ = 'user'

    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 '' % self.username

class Article(db.Model):
    __bind_key__ = 'appmeta'
    __tablename__ = 'article'

    id = db.Column(db.Integer, primary_key=True)
    title = db.Column(db.String(80), unique=True)
    content = db.Column(db.String(120), unique=True)

    def __init__(self, title, content):
        self.title = title
        self.content = content

    def __repr__(self):
        return '