python---ORM之SQLAlchemy（5）联合唯一的使用

# coding:utf8
# __author:  Administrator
# date:      2018/3/16 0016
# /usr/bin/env python
import sqlalchemy
from sqlalchemy import create_engine
from sqlalchemy import String,Column,Integer,ForeignKey,UniqueConstraint
from sqlalchemy.orm import relationship,sessionmaker
from sqlalchemy.ext.declarative import declarative_base

engine = create_engine("mysql+pymysql://root:root@127.0.0.1/t2")

Base = declarative_base()

class Test(Base):
    __tablename__ = 'test'
    id = Column(Integer,primary_key=True)
    name = Column(String(40))
    age = Column(Integer)

　　#在__table_args__中设置索引，为元组
    __table_args__ = (
        UniqueConstraint('name','age'),#姓名和年龄唯一

)

Base.metadata.create_all(engine) 

MySession = sessionmaker(bind=engine) 

session = MySession() 

t1 = Test(name='asd',age=11) 
t2 = Test(name='asd',age=12) 

session.add_all([t1,t2]) 

session.commit()

上面是可以成功的，但是当你想再添加一个，name，age相同的数据是，会报错

t3 = Test(name='asd',age=11)

session.add(t3)
session.commit()

#sqlalchemy.exc.IntegrityError: (pymysql.err.IntegrityError) (1062, "Duplicate entry 'asd-11' for key 'name'") [SQL: 'INSERT INTO test (name, age) VALUES (%(name)s, %(age)s)'] [parameters: {'name': 'asd', 'age': 11}] (Background on this error at: http://sqlalche.me/e/gkpj)