pymongo来操作MongoDB数据库，但是直接把对于数据库的操作代码都写在脚本中，这会让应用的代码耦合性太强，而且不利于代码的优化管理
一般应用都是使用MVC框架来设计的，为了更好地维持MVC结构，需要把数据库操作部分作为model抽离出来，这就需要借助MongoEngine
MongoEngine是一个对象文档映射器（ODM），相当于一个基于SQL的对象关系映射器（ORM）
MongoEngine提供的抽象是基于类的，创建的所有模型都是类
安装
pip install mongoengine
使用时先声明一个继承自MongoEngine.Document的类
在类中声明一些属性，相当于创建一个用来保存数据的数据结构，即数据已类似数据结构的形式存入数据库中，通常把这样的一些类都存放在一个脚本中，作为应用的Model模块
from mongoengine import *connect('test', host='localhost', port=27017)import datetimeclass Users(Document): name = StringField(required=True, max_length=200) age = IntField(required=True)users = Users.objects.all() #返回所有的文档对象列表for u in users: print("name:",u.name,",age:",u.age)
保存文档
from mongoengine import *connect('test', host='localhost', port=27017)import datetimeclass Users(Document): name = StringField(required=True, max_length=200) age = IntField(required=True)user1 = Users( name='zz', age= 11)user1.save()print(user1.name)user1.name = 'zz11'user1.save()print(user1.name)
查询10=<年龄<30的，按姓名排列
from mongoengine import *connect('test', host='localhost', port=27017)import datetimeclass Users(Document): name = StringField(required=True, max_length=200) age = IntField(required=True)user_search = Users.objects(age__gte=10, age__lt=33).order_by('name')for u in user_search: print("name:",u.name,",age:",u.age)
查询10=<年龄<30的，按姓名倒序
from mongoengine import *connect('test', host='localhost', port=27017)import datetimeclass Users(Document): name = StringField(required=True, max_length=200) age = IntField(required=True)user_search = Users.objects(age__gte=10, age__lt=33).order_by('-name')for u in user_search: print("name:",u.name,",age:",u.age)
查询name=zz11
from mongoengine import *connect('test', host='localhost', port=27017)import datetimeclass Users(Document): name = StringField(required=True, max_length=200) age = IntField(required=True)tmp = Users.objects(name="zz11")for u in tmp: print("name:",u.name,",age:",u.age)
修改name=zz11的age加1
from mongoengine import *connect('test', host='localhost', port=27017)import datetimeclass Users(Document): name = StringField(required=True, max_length=200) age = IntField(required=True)tmp = Users.objects(name="zz11").update(inc__age=1)tmp = Users.objects(name="zz11")for u in tmp: print("name:",u.name,",age:",u.age)
修改name=zz11的age设为55
from mongoengine import *connect('test', host='localhost', port=27017)import datetimeclass Users(Document): name = StringField(required=True, max_length=200) age = IntField(required=True)tmp = Users.objects(name="zz11").update(set__age=55)tmp = Users.objects(name="zz11")for u in tmp: print("name:",u.name,",age:",u.age)
