python flask框架 数据库的使用

 #coding:utf8

 from flask import Flask
 from flask_sqlalchemy import SQLAlchemy

 app = Flask(__name__)

 # 设置链接数据库的url
 app.config['SQLALCHEMY_DATABASE_URI']='mysql://root:mysql@127.0.0.1:3306/flask'

 # 每次请求结束后自动提交数据
 app.config['SQLALCHEMY_COMMIT_ON_TEAMDOWN'] = True

 app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = True

 # 查询时会显示原始的sql语句
 app.config['SQLALCHEMY_ECHO'] = True

 # 注册数据库
 db = SQLAlchemy(app)

 class Role(db.Model):
     # 定义表名
     __tablename__ = 'roles'
     # 定义列对象
     id = db.Column(db.Integer,primary_key=True)
     name = db.Column(db.String(64),unique=True)

     # 关系字段 用于两个方向查
     user = db.relationship('User',backref='rel')

     # repr() 方法现实一个可读字符串
     def __repr__(self):
         return str(self.name)

 class User(db.Model):
     __tablename__ = 'users'
     id = db.Column(db.Integer,primary_key=True)
     name = db.Column(db.String(64),unique=True,index=True)
     email = db.Column(db.String(64),unique=True)
     pswd = db.Column(db.String(64))
     role_id = db.Column(db.Integer,db.ForeignKey("roles.id"))

     def __repr__(self):
         return str(self.name)

 if __name__ == '__main__':
     db.drop_all()   # 删除表
     db.create_all() # 创建表
     ro1 = Role(name = 'admin')  # 创建对象
     ro2 = Role(name = 'user' )
     # 向数据库添加数据
     db.session.add_all([ro1,ro2])
     # 提交
     # db.session.commit()

     us1 = User(name='wang', email='wang@163.com', pswd='', role_id=ro1.id)
     us2 = User(name='zhang', email='zhang@189.com', pswd='', role_id=ro2.id)
     us3 = User(name='chen', email='chen@126.com', pswd='', role_id=ro2.id)
     us4 = User(name='zhou', email='zhou@163.com', pswd='', role_id=ro1.id)
     db.session.add_all([us1, us2, us3, us4])
     db.session.commit()

     app.run(debug=True)