说是触发器，其实并不是触发器，这是sqlalchemy中的钩子，也称为事件，在触发某个操作的时候执行某个函数，和sql中的触发器时一样的，更加灵活简单。
我现在也正在学习，我就直接拿出来一个例子吧，大家可以测试一下。
#coding:utf8
from sqlalchemy.orm import scoped_session
from sqlalchemy import Column, Integer, String, DateTime, TIMESTAMP, DECIMAL, func, Text, or_
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.exc import SQLAlchemyError
from sqlalchemy import ForeignKey, Boolean, create_engine, MetaData, Constraint
from sqlalchemy.orm import relationship, backref, sessionmaker
from sqlalchemy import event
Base = declarative_base()
class Role(Base):# 一
__tablename__= 'roles'
id = Column(Integer,primary_key=True)
name = Column(String(36),nullable=True)
users = relationship('User',backref='role')
class User(Base):# 多
__tablename__ = 'users'
id = Column(Integer,primary_key=True)
name = Column(String(36),nullable=True)
role_id = Column(Integer, ForeignKey('roles.id'))
class Database():
def __init__(self, bind, pool_size=100, pool_recycle=3600, echo=False):
self.__engine = create_engine(bind,pool_size=pool_size,
pool_recycle=pool_recycle,
echo=echo)
self.__session_factory = sessionmaker(bind=self.__engine)
self.__db_session = scoped_session(self.__session_factory)
Base.metadata.create_all(self.__engine)
@property
def session(self):
return self.__db_session()
def on_created(target, value, initiator):
print "received append event for target: %s" % target
@event.listens_for(User, 'after_insert')
def receive_after_insert(mapper, connection, target):
print mapper
print connection
print target.id
print "insert......."
db = Database(bind="mysql+pymysql://root:xxxx@localhost/mydata?charset=utf8")
if __name__ == "__main__":
user = User()
user.name = "123"
user.role_id=2
db.session.add(user)
db.session.commit()
在插入数据后会执行receive_after_insert函数，很简单。
如果想深入的学习建议看官方文档，说的很详细
http://docs.sqlalchemy.org/en/latest/orm/events.html#attribute-events