Python中使用MongoEngine

pymongo來操作MongoDB數據庫，但是直接把對於數據庫的操作代碼都寫在腳本中，這會讓應用的代碼耦合性太強，而且不利於代碼的優化管理

一般應用都是使用MVC框架來設計的，為了更好地維持MVC結構，需要把數據庫操作部分作為model抽離出來，這就需要借助MongoEngine

MongoEngine是一個對象文檔映射器（ODM），相當於一個基於SQL的對象關系映射器（ORM）

MongoEngine提供的抽象是基於類的，創建的所有模型都是類

 安裝

pip install mongoengine

使用時先聲明一個繼承自MongoEngine.Document的類

在類中聲明一些屬性，相當於創建一個用來保存數據的數據結構，即數據已類似數據結構的形式存入數據庫中，通常把這樣的一些類都存放在一個腳本中，作為應用的Model模塊

from mongoengine import *
connect('test', host='localhost', port=27017)
import datetime
class Users(Document):
    name = StringField(required=True, max_length=200)
    age = IntField(required=True)

users = Users.objects.all() #返回所有的文檔對象列表
for u in users:
    print("name:",u.name,",age:",u.age)

保存文檔

from mongoengine import *
connect('test', host='localhost', port=27017) import datetime class 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)

 查詢10=<年齡<30的，按姓名排列

from mongoengine import *
connect('test', host='localhost', port=27017) import datetime class 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)

 查詢10=<年齡<30的，按姓名倒序

from mongoengine import *
connect('test', host='localhost', port=27017) import datetime class 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)

查詢name=zz11

from mongoengine import *
connect('test', host='localhost', port=27017) import datetime class 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 datetime class 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設為55

from mongoengine import *
connect('test', host='localhost', port=27017) import datetime class 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)