from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker
engine = create_engine('mysql://pass@localhost/test'echo=True)
DBSession = sessionmaker(bind=engine)
session = DBSession()
ret=session.execute('desc user')
print ret
# print ret.fetchall()
print ret.first()

from sqlalchemy import Column
from sqlalchemy.types import *
from sqlalchemy.ext.declarative import declarative_base

BaseModel = declarative_base()

from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker

engine = create_engine('mysql://root:Hs2BitqLYKoruZJbT8SV@localhost/test')
DBSession = sessionmaker(bind=engine)


class User(BaseModel):
  __tablename__ = 'user1' # 表名
  user_name = Column(CHAR(30), primary_key=True)
  pwd = Column(VARCHAR(20), default='aaa', nullable=False)
  age = Column(SMALLINT(), server_default='12')
  accout = Column(INT())
  birthday = Column(TIMESTAMP())
  article = Column(TEXT())
  height = Column(FLOAT())


def init_db():
  '''
  初始化数据库
  :return:
  '''
  BaseModel.metadata.create_all(engine)


def drop_db():
  '''
  删除所有数据表
  :return:
  '''
  BaseModel.metadata.drop_all(engine)


drop_db()
init_db()

user1=User(user_name='lujianxing',accout=1245678)
session.add(user1)
session.commit()

query = session.query(User) 
user = query.get('lujianxing11')
print user.accout
user.accout='987'
session.flush()

query = session.query(User)
query.filter(User.user_name=='lujianxing2').update({User.age: '15'})
query.filter(User.user_name=='lujianxing2').update({'age': '16'})
query.filter(User.pwd=='aaa').update({'age': '17'})

query = session.query(User)
user = query.get('lujianxing11')
session.delete(user)
session.flush()

query = session.query(User)
print query # 只显示sql语句，不会执行查询
print query[0] # 执行查询
print query.all() # 执行查询
print query.first() # 执行查询
for user in query: # 执行查询
  print user.user_name

# 筛选
user = query.get(1) # 根据主键获取
print query.filter(User.user_name == 2) # 只显示sql语句，不会执行查询
print query.filter(User.user_name == 'lujianxing').all() # 执行查询
print query.filter(User.user_name == 'lujianxing', User.accout == 1245678, User.age > 10).all() # 执行查询
print query.filter(User.user_name == 'lujianxing').filter(User.accout == 1245678).all()
print query.filter("user_name = 'lujianxing'").all() # 执行查询
print query.filter("user_name = 'lujianxing' and accout=1245678").all() # 执行查询
query2 = session.query(User.user_name) # 返回的结果不是User的实例，而是元组
print query2.all() # 执行查询
print query2.offset(1).limit(1).all() # 等于 limit 1,1
# 排序
print query2.order_by(User.user_name).all() 
print query2.order_by('user_name').all() 
print query2.order_by(User.user_name.desc()).all()
print query2.order_by(User.user_name, User.accout.desc()).all()
print query2.filter("user_name = 'lujianxing' and accout=1245678").count()
# 聚合查询
print session.query(func.count('*')).select_from(User).scalar()
print session.query(func.count('1')).select_from(User).scalar()
print session.query(func.count(User.id)).scalar()
print session.query(func.count('*')).filter(User.id > 0).scalar() # filter() 中包含 User，因此不需要指定表
print session.query(func.count('*')).filter(User.name == 'a').limit(1).scalar() == 1 # 可以用 limit() 限制 count() 的返回数
print session.query(func.sum(User.id)).scalar()
print session.query(func.now()).scalar() # func 后可以跟任意函数名，只要该数据库支持
print session.query(func.current_timestamp()).scalar()
print session.query(func.md5(User.name)).filter(User.id == 1).scalar()