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初步学习了peewee，因为sqlalchemy实在是太重量级，文档也太恶心，peewee上手容易得多，也非常light

结合celery和peewee，写了点东西，查询年龄

myapp/db.py：

from __future__ import absolute_import
from myapp.celery import app
from peewee import *db = SqliteDatabase('people.db')
class Person(Model):name = CharField()age = IntegerField()class Meta:database = db@app.task
def agequery(name):db.connect()#   collection = []for i in Person.select().where(Person.name == name):return {'name':name,'age':i.age}#    collection.append({'name':name,'age':i.age})#  return collectiondb.close()@app.task
def savedata(message):db.connect()newdata = Person.create(name=message.get('name'),age=message.get('age'))newdata.save()db.close()@app.task
def initdb():db.connect()db.create_tables([Person,])db.close()

测试用例：

Python 2.7.6 (default, Mar 22 2014, 22:59:56)
[GCC 4.8.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from myapp.db import savedata,agequery
>>> res = agequery('miaoting')
>>> res = agequery.delay('miaoting')
>>> res.get()
{u'age': 17, u'name': u'miaoting'}
>>> savedata({'name':'Jc','age':65})
>>> savedata.delay({'name':'Jc','age':65})
<AsyncResult: c6d06e50-42b3-42a1-b06b-2561eb0c64af>
>>> res = agequery.delay('Jc')
>>> res.get()
{u'age': 65, u'name': u'Jc'}
>>> savedata.delay({'name':'FanShu','age':99})
<AsyncResult: a348b074-a6f1-430c-af78-42d8e29cf4e6>
>>> res = agequery.delay('Fanshu')
>>> res.get()
>>> res = agequery.delay('Jc')
>>> res.get()
{u'age': 65, u'name': u'Jc'}
>>> res = agequery.delay('Fanshu')
>>> res.get()
>>> res = agequery.delay('FanShu')
>>> res.get()

第一次使用db时要用initdb初始化，除非删除sqlite数据库，否则只需调用savedata和agequery

peewee笔记:

peewee 学习：

在peewee中，一个继承model类的类定义为某个数据库的一个表格

类中的feild，为数据库的列（字段）

一个model类实例则是一行

example：

from peewee import *

db = SqliteDatabase('people.db')

class Person(Model):

name = CharField()

birthday = DateField()

is_relative = BooleanField()

class Meta:

database = db # This model uses the "people.db" database.

class Pet(Model):

owner = ForeignKeyField(Person, related_name='pets')

name = CharField()

animal_type = CharField()

class Meta:

database = db # this model uses the "people.db" database

db.connect()

db.create_tables([Person, Pet])

保存数据：

>>> from datetime import date

>>> uncle_bob = Person(name='Bob', birthday=date(1960, 1, 15), is_relative=True)

>>> uncle_bob.save() # bob is now stored in the database

1

>>> bob_kitty = Pet.create(owner=uncle_bob, name='Kitty', animal_type='cat')

>>> herb_fido = Pet.create(owner=herb, name='Fido', animal_type='dog')

>>> herb_mittens = Pet.create(owner=herb, name='Mittens', animal_type='cat')

>>> herb_mittens_jr = Pet.create(owner=herb, name='Mittens Jr', animal_type='cat')

删除数据：

>>> herb_mittens.delete_instance() # he had a great life

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查询数据（根据类的feild访问相关字段的数据）：

>>> grandma = Person.select().where(Person.name == 'Grandma L.').get()

>>> grandma = Person.get(Person.name == 'Grandma L.')

列出所有记录：

>>> for person in Person.select():

...     print person.name, person.is_relative

...

Bob True

Grandma L. True

Herb False

比较两种查询的区别：

>>> query = Pet.select().where(Pet.animal_type == 'cat')

>>> for pet in query:

...     print pet.name, pet.owner.name

...

Kitty Bob

Mittens Jr Herb

>>> query = (Pet

...          .select(Pet, Person)

...          .join(Person)

...          .where(Pet.animal_type == 'cat'))

>>> for pet in query:

...     print pet.name, pet.owner.name

...

Kitty Bob

Mittens Jr Herb

后者的效率更高，后者不做无谓查询