Question

官方文档:

http://api.mongodb.org/python/current/tutorial.html

安装

sudo pip install pymongo

测试Python驱动

启动ipython:

import pymongo client=pymongo.MongoClient("127.0.0.1", 27017) #Getting a Database¶ db=client.test_database #Getting a Collection collection = db.test_collection post={"name":"xwp1", "age":32} #Inserting a Document post_id = collection.insert_one(post).inserted_id db.collection_names() post={"name":"xwp2", "age":33} post_id = collection.insert_one(post).inserted_id collection.find_one() for cur in collection.find(): print cur cur=collection.find() cur.next() cur.next() cur.next() print collection.count() collection.find({"name":"xwp"}).count() collection.find({"name":"xwp1"}).count()

Aggregation Examples

首先，插入一些数据进行聚合：

db = client.aggregation_example
result = db.things.insert_many([
                                {"x":1,"tags":["dog","cat"]},
                                {"x":2,"tags":["cat"]},
                                {"x":2,"tags":["mouse","cat","dog"]},
                                {"x":3,"tags":[]}
                              ])
result.inserted_ids
[ObjectId('...'), ObjectId('...'), ObjectId('...'), ObjectId('...')]

Python字典不含有排序语法，需要使用的SON：

from bson.son import SON
pipeline = [
        {"$unwind": "$tags"},
        {"$group": {"_id": "$tags", "count": {"$sum": 1}}},
        {"$sort": SON([("count", -1), ("_id", -1)])}
    ]
list(db.things.aggregate(pipeline))
[{u'count': 3, u'_id': u'cat'}, {u'count': 2, u'_id': u'dog'}, {u'count': 1, u'_id': u'mouse'}]

可以使用command()方法 运行一个聚合explain方法：

db.command('aggregate', 'things', pipeline=pipeline, explain=True)
{u'ok': 1.0,
 u'stages': [{u'$cursor': {u'fields': {u'_id': 0, u'tags': 1},
    u'query': {},
    u'queryPlanner': {u'indexFilterSet': False,
     u'namespace': u'aggregation_example.things',
     u'parsedQuery': {u'$and': []},
     u'plannerVersion': 1,
     u'rejectedPlans': [],
     u'winningPlan': {u'direction': u'forward',
      u'filter': {u'$and': []},
      u'stage': u'COLLSCAN'}}}},
  {u'$unwind': {u'path': u'$tags'}},
  {u'$group': {u'_id': u'$tags', u'count': {u'$sum': {u'$const': 1}}}},
  {u'$sort': {u'sortKey': {u'_id': -1, u'count': -1}}}],
 u'waitedMS': 0L}

执行 explain=False

db.command('aggregate', 'things', pipeline=pipeline, explain=False)
{u'ok': 1.0,
 u'result': [{u'_id': u'cat', u'count': 3},
  {u'_id': u'dog', u'count': 2},
  {u'_id': u'mouse', u'count': 1}],
 u'waitedMS': 0L}