Mongoengine 简明教程

D:\mongodb\bin>mongod

D:\mongodb\bin>mongo

E:\mongodb\bin>mongo
MongoDB shell version v4.0.6
connecting to: mongodb://127.0.0.1:27017/?gssapiServiceName=mongodb
Implicit session: session { "id" : UUID("0d848b11-acf7-4d30-83df-242d1d7fa693") }
MongoDB server version: 4.0.6
---
>

> db
Test

> use mydb
switched to db mydb

<<< from pymongo import MongoClient
<<< client=MongoClient()

db=client.mydatabase

pip install mongoengine

python setup.py install

>>> import mongoengine
>>> mongoengine.__version__
'0.19.1'

from mongoengine import connect
connect(‘mydata.db’)

connect('mydata.db', host='192.168.1.1', port=12345)

connect('mydata.db', username='user1', password='***', authentication_source='admin')

connect('mydata.db', host='mongodb://localhost/database_name')

connect(host='mongodb://localhost/dbname?replicaSet=rs-name')

connect(alias='db1', db='db1.db')
connect(alias='db2', db='db2.db')

from mongoengine import *
class Student(Document):
   studentid = StringField(required=True)
   name = StringField(max_length=50)
   age = IntField()
   def _init__(self, id, name, age):
      self.studentid=id,
      self.name=name
      self.age=age

meta={collection': 'student_collection'}

s1=Student('A001', 'Tara', 20)
s1.save()

>>> class student(DynamicDocument):
... name=StringField()

>>> s1=student()
>>> s1.name="Tara"
>>> connect('mydb')
>>> s1.save()

>>> s2=student()
>>> setattr(s2,'age',20)
>>> s2.name='Lara'
>>> s2.save()

BaseField(db_field, required, default, unique, primary_key)

class MyDocument(Document):
   ...
   ...

   def clean(self):
      if <condition>==True:
         msg = 'error message.'
         raise ValidationError(msg)

from mongoengine import *
con=connect('newdb')
dbs=con.list_database_names()
for db in dbs:
print (db)

collections=con['newdb'].list_collection_names()
for collection in collections:
   print (collection)

from mongoengine import *
con=connect('newdb')
class products (Document):
ProductID=IntField(required=True)
Name=StringField()
price=IntField()
for product in products.objects:
print ('ID:',product.ProductID, 'Name:',product.Name, 'Price:',product.price)

for product in products.objects(Name='TV'):
print ('ID:',product.ProductID, 'Name:',product.Name, 'Price:',product.price)

qset=products.objects
for product in qset.filter(Name='TV'):
   print ('ID:',product.ProductID, 'Name:',product.Name, 'Price:',product.price)

#using greater than operator
for product in products.objects(price__gt=10000):
   print ('ID:',product.ProductID, 'Name:',product.Name, 'Price:',product.price)

Qset.order_by(‘fieldname’)

from mongoengine import *
con=connect('newdb')

class products (Document):
   ProductID=IntField(required=True)
   company=StringField()
   Name=StringField()
   price=IntField()
for product in products.objects.order_by('price'):
   print ("Name:{} company:{} price:{}".format(product.Name, product.company, product.price))

@queryset_manager
   def qry_method(docs_cls,queryset):
       ….
       ----

from mongoengine import *
con=connect('newdb')

class products (Document):
   ProductID=IntField(required=True)
   company=StringField()
   Name=StringField()
   price=IntField()

   @queryset_manager
   def expensive_prods(docs_cls,queryset):
      return queryset.filter(price__gt=20000)
for product in products.expensive_prods():
   print ("Name:{} company:{} price:{}".format(product.Name, product.company, product.price))

from mongoengine import *
con=connect('mydata')
class student(Document):
   name=StringField(required=True)
   course=StringField()
   meta = {'indexes':['name']}

s1=student()
s1.name='Avinash'
s1.course='DataScience'
s1.save()
s2=student()
s2.name='Anita'
s2.course='WebDesign'
s2.save()

from mongoengine import *
con=connect('mydata')

class student(Document):
   name=StringField(required=True)
   course=StringField()
   meta = {'indexes':[('name','-course')]}

s1=student()
s1.name='Avinash'
s1.course='DataScience'
s1.save()
s2=student()
s2.name='Anita'
s2.course='WebDesign'
s2.save()

from mongoengine import *
con=connect('mydata')

class student(Document):
   name=StringField(required=True)
   course=StringField()
   meta = {'indexes':[{
            'fields': ['name'],
            'expireAfterSeconds': 3600
           }
    ]
}

print (student.list_indexes())

[[('name', 1)], [('_id', 1)]]

class student(Document):
name=StringField(required=True)
course=StringField()
meta = {'indexes':[{
          'fields': ['name'],
          'expireAfterSeconds': 3600
        }
]}
student.create_index(['course'])

from mongoengine import *
con=connect('mydata')

class orders(Document):
   custID = StringField()
   amount= IntField()
   status = StringField()

 pipeline = [
{"$match" : {"status" : "A"}},
{"$group": {"_id": "$custID", "total": {"$sum": "$amount"}}}
]

docs = orders.objects().aggregate(pipeline)

from mongoengine import *
con=connect('mydata')

class orders(Document):
   custID = StringField()
   amount= IntField()
   status = StringField()

pipeline = [
   {"$match" : {"status" : "A"}},
   {"$group": {"_id": "$custID", "total": {"$sum": "$amount"}}}
   ]
docs = orders.objects().aggregate(pipeline)
for doc in docs:
   print (x)

{'_id': 'B212', 'total': 400}
{'_id': 'A123', 'total': 750}

from mongoengine import *
con=connect('newdb')
class person (Document):
name=StringField(required=True)
city=StringField(default='Mumbai')
pin=IntField()
p1=person(name='Himanshu', city='Delhi', pin=110012).save()
doc=person.objects.only('name').first()
print ('name:',doc.name)
print ('city:', doc.city)
print ('PIN:', doc.pin)

from mongoengine import *
con=connect('newdb')
class employee (Document):
name=StringField(required=True)
branch=StringField()
meta={'allow_inheritance':True}
class salary(employee):
dept=StringField()
sal=IntField()
e1=employee(name='Bharat', branch='Chennai').save()
s1=salary(name='Deep', branch='Hyderabad', dept='Accounts', sal=25000).save()

{
"_id":{"$oid":"5ebc34f44baa3752530b278a"},
"_cls":"employee",
"name":"Bharat",
"branch":"Chennai"
}
{
"_id":{"$oid":"5ebc34f44baa3752530b278b"},
"_cls":"employee.salary",
"name":"Deep",
"branch":"Hyderabad",
"dept":"Accounts",
"sal":{"$numberInt":"25000"}
}

from mongoengine import *
con=connect('newdb')

class shape (Document):
   meta={'abstract':True}
   def area(self):
      pass

class rectangle(shape):
   width=IntField()
   height=IntField()
   def area(self):
      return self.width*self.height

r1=rectangle(width=20, height=30).save()

from mongoengine import *
con=connect('newdb')

class tests (Document):
   name=StringField()
   attempts=IntField()
   scores=ListField(IntField())

t1=tests()
t1.name='XYZ'
t1.attempts=0
t1.scores=[]
t1.save()

tests.objects(name='XYZ').update_one(set__name='MongoDB')

tests.objects(name='MongoDB').update_one(push__scores=50)

tests.objects(name='MongoDB').update_one(inc__attempts=1)

{
"_id":{"$oid":"5ebcf8d353a48858e01ced04"},
"name":"MongoDB",
"attempts":{"$numberInt":"1"},
"scores":[{"$numberInt":"50"}]
}

exec_js(code, *field_names, **options)

class BlogPost(Document):
title = StringField(db_field='doctitle')

document': doc[~title];

from mongoengine import *
con=connect('newdb')

class lang (Document):
   name=StringField()
   developer=StringField()
   logo=FileField()

l1=lang()
l1.name='Python'
l1.developer='Van Rossum'
f=open('pylogo.png','rb')
l1.logo.put(f,content_type='image/png')
l1.save()

logo = l1.logo.read()

l1 = lang.objects(name='Python').first()
l1.logo.delete()
l1.save()

l1 = lang.objects(name='Python').first()
f=open('newlogo.png','rb')
l1.logo.replace(f,content_type='image/png')
l1.save()

from mongoengine import *
from mongoengine import signals
import logging
logging.basicConfig(level=logging.DEBUG)

class Author(Document):
   name = StringField()

   def __unicode__(self):
      return self.name

   @classmethod
   def pre_save(cls, sender, document, **kwargs):
      logging.debug("Pre Save: %s" % document.name)

   @classmethod
   def post_save(cls, sender, document, **kwargs):
      logging.debug("Post Save: %s" % document.name)
      if 'created' in kwargs:
         if kwargs['created']:
            logging.debug("Created")
         else:
            logging.debug("Updated")

signals.pre_save.connect(Author.pre_save, sender=Author)
signals.post_save.connect(Author.post_save, sender=Author)

Author(name="Lathkar").save()

DEBUG:root:Pre Save: Lathkar
DEBUG:root:Post Save: Lathkar
DEBUG:root:Created

from mongoengine import *
con=connect('newdb')

class lang (Document):
   name=StringField()
   features=StringField()
   meta = {'indexes': [
      {'fields': ['$name', "$features"],
         'default_language': 'english',
         'weights': {'name': 2, 'features': 10}
      }]
   }

l1=lang()
l1.name='C++'
l1.features='Object oriented language for OS development'
l1.save()
l2=lang()
l2.name='Python'
l2.features='dynamically typed and object oriented for data science, AI and ML'
l2.save()
l3=lang()
l3.name='HTML'
l3.features='scripting language for web page development'
l3.save()

docs=lang.objects.search_text('oriented')
for doc in docs:
   print (doc.name)