# coding:utf8
from flask import Flask
from flask_sqlalchemy import SQLAlchemy
app = Flask(__name__)
#app.config.from_pyfile('config')
db = SQLAlchemy(app)
app.config['SECRET_KEY'] = 'what s the s'
app.config['SQLALCHEMY_DATABASE_URI'] = 'mysql://root:pass@localhost:3306/table'
app.config['SQLALCHEMY_COMMIT_ON_TEARDOWN'] = True
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = True
temp = 0
class Comment(db.Model):
__tablename__ = 'Comment'
id = db.Column(db.Integer, primary_key=True)
comment = db.Column(db.String(128))
created = db.Column(db.DateTime, index=True, default=datetime.datetime.utcnow())
global temp
pid = db.Column(db.Integer)#, default=temp)
role_id = db.Column(db.Integer）#, db.ForeignKey('Role.id'))
arc_id = db.Column(db.Integer）#, db.ForeignKey('Article.id'))
to_role_id = db.Column(db.Integer)
@staticmethod
def set_pid(target, value, oldvalue, initiator):
if not target.to_role_id:
global temp
temp += 1
target.pid = temp
#使用set方法 在传入表单中没有to_role_id的值的时候 自动调用set_id函数，以想要的方式存入数据库
db.event.listen(Comment.arc_id if Comment.to_role_id else Comment.to_role_id,'set',Comment.set_pid)
#当listen的第一个参数为空的时候不执行set_pid函数中的代码
if __name__ == '__main__':
#db.create_all() 首先创建表单
s = Comment(comment='cscs', role_id=1, arc_id=2)
s1 = Comment(comment='cscs', role_id=1, arc_id=2)
s2 = Comment(comment='cscs', role_id=2, arc_id=2,to_role_id=1,pid=2)
db.session.add(s)
db.session.add(s1)
db.session.add(s2)
db.session.commit()
