多对一
#!/usr/bin/env python
# -*- coding:utf-8 -*-
import time
import threading
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, Integer, String, ForeignKey, UniqueConstraint, Index
from sqlalchemy.orm import sessionmaker, relationship
from sqlalchemy import create_engine
Base = declarative_base()
class Hobby(Base):
__tablename__ = 'hobby'
id = Column(Integer, primary_key=True)
caption = Column(String(50), default='篮球')
class Person(Base):
__tablename__ = 'person'
nid = Column(Integer, primary_key=True)
name = Column(String(32), index=True, nullable=True)
hobby_id = Column(Integer, ForeignKey("hobby.id"))
# 与生成表结构无关，仅用于查询方便
hobby = relationship("Hobby", backref='pers')
def init_db():
"""
根据类创建数据库表
:return:
"""
engine = create_engine(
"mysql+pymysql://root:[email protected]:3306/test?charset=utf8",
max_overflow=0, # 超过连接池大小外最多创建的连接
pool_size=5, # 连接池大小
pool_timeout=30, # 池中没有线程最多等待的时间，否则报错
pool_recycle=-1 # 多久之后对线程池中的线程进行一次连接的回收（重置）
)
Base.metadata.create_all(engine)
if __name__ == '__main__':
# drop_db()
init_db()
engine = create_engine("mysql+pymysql://root:[email protected]:3306/test?charset=utf8", max_overflow=0, pool_size=5)
Session = sessionmaker(bind=engine)
session = Session()
####################################多对一添加#######################################
# 添加方式一
# session.add_all([
# Hobby(caption='乒乓球'),
# Hobby(caption='羽毛球'),
# Person(name='张三', hobby_id=1),
# Person(name='李四', hobby_id=2),
# ])
#添加方式二
# person = Person(name='张九', hobby=Hobby(caption='姑娘'))
# session.add(person)
# 添加方式三
# hb = Hobby(caption='人妖')
# hb.pers = [Person(name='文飞'), Person(name='博雅')]
# session.add(hb)
# session.commit()
# #######################################relationship正向查询#######################################
v = session.query(Person).first()
print(v.name)
print(v.hobby.caption)
# #######################################relationship反向查询#######################################
v = session.query(Hobby).first()
print(v.caption)
print(v.pers)
session.close()
多对多
#!/usr/bin/env python
# -*- coding:utf-8 -*-
import time
import threading
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, Integer, String, ForeignKey, UniqueConstraint, Index
from sqlalchemy.orm import sessionmaker, relationship
from sqlalchemy import create_engine
Base = declarative_base()
class Server2Group(Base):
__tablename__ = 'server2group'
id = Column(Integer, primary_key=True, autoincrement=True)
server_id = Column(Integer, ForeignKey('server.id'))
group_id = Column(Integer, ForeignKey('group_.id'))
class Group(Base):
__tablename__ = 'group_'
id = Column(Integer, primary_key=True)
name = Column(String(64), unique=True, nullable=False)
# 与生成表结构无关，仅用于查询方便
servers = relationship('Server', secondary='server2group', backref='groups')
class Server(Base):
__tablename__ = 'server'
id = Column(Integer, primary_key=True, autoincrement=True)
hostname = Column(String(64), unique=True, nullable=False)
def init_db():
"""
根据类创建数据库表
:return:
"""
engine = create_engine(
"mysql+pymysql://root:[email protected]:3306/test?charset=utf8",
max_overflow=0, # 超过连接池大小外最多创建的连接
pool_size=5, # 连接池大小
pool_timeout=30, # 池中没有线程最多等待的时间，否则报错
pool_recycle=-1 # 多久之后对线程池中的线程进行一次连接的回收（重置）
)
Base.metadata.create_all(engine)
if __name__ == '__main__':
# drop_db()
init_db()
engine = create_engine("mysql+pymysql://root:[email protected]:3306/test?charset=utf8", max_overflow=0, pool_size=5)
Session = sessionmaker(bind=engine)
session = Session()
####################################多对一添加#######################################
# 方式一
# session.add_all([
# Server(hostname='c1.com'),
# Server(hostname='c2.com'),
# Group(name='A组'),
# Group(name='B组'),
# ])
# session.commit()
#
# s2g = Server2Group(server_id=1, group_id=1)
# session.add(s2g)
# session.commit()
# 方式二
# gp = Group(name='C组')
# gp.servers = [Server(hostname='c3.com'), Server(hostname='c4.com')]
# session.add(gp)
# session.commit()
# 方式三
# ser = Server(hostname='c6.com')
# ser.groups = [Group(name='F组'),Group(name='G组')]
# session.add(ser)
# session.commit()
## # # # # # # # # # # # # # # # # 使用relationship正向查询# # # # # # # # # # # # # # #
v = session.query(Group).first()
print(v.name)
print(v.servers)
for i in v.servers:
print(i.hostname)
## # # # # # # # # # # # # # # # # # # 使用relationship反向查询# # # # # # # # #
v = session.query(Server).first()
print(v.hostname)
print(v.groups)
session.close()
原生语句
#!/usr/bin/env python
# -*- coding:utf-8 -*-
import time
import threading
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, Integer, String, ForeignKey, UniqueConstraint, Index
from sqlalchemy.orm import sessionmaker, relationship
from sqlalchemy import create_engine
Base = declarative_base()
class Server2Group(Base):
__tablename__ = 'server2group'
id = Column(Integer, primary_key=True, autoincrement=True)
server_id = Column(Integer, ForeignKey('server.id'))
group_id = Column(Integer, ForeignKey('group_.id'))
class Group(Base):
__tablename__ = 'group_'
id = Column(Integer, primary_key=True)
name = Column(String(64), unique=True, nullable=False)
# 与生成表结构无关，仅用于查询方便
servers = relationship('Server', secondary='server2group', backref='groups')
class Server(Base):
__tablename__ = 'server'
id = Column(Integer, primary_key=True, autoincrement=True)
hostname = Column(String(64), unique=True, nullable=False)
def init_db():
"""
根据类创建数据库表
:return:
"""
engine = create_engine(
"mysql+pymysql://root:[email protected]:3306/test?charset=utf8",
max_overflow=0, # 超过连接池大小外最多创建的连接
pool_size=5, # 连接池大小
pool_timeout=30, # 池中没有线程最多等待的时间，否则报错
pool_recycle=-1 # 多久之后对线程池中的线程进行一次连接的回收（重置）
)
Base.metadata.create_all(engine)
if __name__ == '__main__':
# drop_db()
init_db()
engine = create_engine("mysql+pymysql://root:[email protected]:3306/test?charset=utf8", max_overflow=0, pool_size=5)
Session = sessionmaker(bind=engine)
session = Session()
# 查询
cursor = session.execute('select * from group_')
result = cursor.fetchall()
print(result)
# 添加
cursor = session.execute('insert into group_(name) values(:value)',params={"value":'GG呵呵'})
session.commit()
print(cursor.lastrowid)
session.close()输出
[(3, 'C组'), (1, 'F组'), (4, 'GG'), (2, 'G组')]
5