【转】Python操作MongoDB数据库

普通连接 client = MongoClient(‘localhost‘, 27017) client = MongoClient(‘mongodb://localhost:27017/‘) # # 密码连接 client = MongoClient(‘mongodb://username:password@localhost:27017/dbname‘) db = client.zfdb # db = client[‘zfdb‘] test = db.test View Code

增

# 增加一条记录
person = {‘name‘: ‘zone‘,‘sex‘:‘boy‘}
person_id = test.insert_one(person).inserted_id
print(person_id)
# 批量插入
persons = [{‘name‘: ‘zone‘, ‘sex‘: ‘boy‘}, {‘name‘: ‘zone1‘, ‘sex‘: ‘boy1‘}]
result = test.insert_many(persons)
print(result.inserted_ids)

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删

# 删除单条记录
result1 = test.delete_one({‘name‘: ‘zone‘})
pprint.pprint(result1)
# 批量删除
result1 = test.delete_many({‘name‘: ‘zone‘})
pprint.pprint(result1)

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改

# 更新单条记录
res = test.update_one({‘name‘: ‘zone‘}, {‘$set‘: {‘sex‘: ‘girl girl‘}})
print(res.matched_count)
# 更新多条记录
test.update_many({‘name‘: ‘zone‘}, {‘$set‘: {‘sex‘: ‘girl girl‘}})

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查

# 查找多条记录
pprint.pprint(test.find())

# 添加查找条件
pprint.pprint(test.find({"sex": "boy"}).sort("name"))

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聚合

如果你是我的老读者，那么你肯定知道我之前的骚操作，就是用爬虫爬去数据之后，用聚合统计结合可视化图表进行数据展示。

aggs = [
    {"$match": {"$or" : [{"field1": {"$regex": "regex_str"}}, {"field2": {"$regex": "regex_str"}}]}}, # 正则匹配字段
    {"$project": {"field3":1, "field4":1}},# 筛选字段 
    {"$group": {"_id": {"field3": "$field3", "field4":"$field4"}, "count": {"$sum": 1}}}, # 聚合操作
]

result = test.aggregate(pipeline=aggs)

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例子：以分组的方式统计 sex 这个关键词出现的次数，说白了就是统计有多少个男性，多少个女性。

test.aggregate([{‘$group‘: {‘_id‘: ‘$sex‘, ‘weight‘: {‘$sum‘: 1}}}])

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聚合效果图：（秋招季，用Python分析深圳程序员工资有多高？文章配图）  

Motor（异步）

Motor 是一个异步实现的 MongoDB 存储库 Motor 与 Pymongo 的配置基本类似。连接对象就由 MongoClient 变为 AsyncIOMotorClient 了。下面进行详细介绍一下。

连接

# 普通连接
client = motor.motor_asyncio.AsyncIOMotorClient(‘mongodb://localhost:27017‘)
# 副本集连接
client = motor.motor_asyncio.AsyncIOMotorClient(‘mongodb://host1,host2/?replicaSet=my-replicaset-name‘)
# 密码连接
client = motor.motor_asyncio.AsyncIOMotorClient(‘mongodb://username:password@localhost:27017/dbname‘)
# 获取数据库
db = client.zfdb
# db = client[‘zfdb‘]
# 获取 collection
collection = db.test
# collection = db[‘test‘]

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增加一条记录

添加一条记录。

async def do_insert():
     document = {‘name‘: ‘zone‘,‘sex‘:‘boy‘}
     result = await db.test_collection.insert_one(document)
     print(‘result %s‘ % repr(result.inserted_id))
loop = asyncio.get_event_loop()
loop.run_until_complete(do_insert())

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批量增加记录

添加结果如图所暗示。

async def do_insert():
    result = await db.test_collection.insert_many(
        [{‘name‘: i, ‘sex‘: str(i + 2)} for i in range(20)])
    print(‘inserted %d docs‘ % (len(result.inserted_ids),))

loop = asyncio.get_event_loop()
loop.run_until_complete(do_insert())

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查找一条记录

async def do_find_one():
    document = await db.test_collection.find_one({‘name‘: ‘zone‘})
    pprint.pprint(document)

loop = asyncio.get_event_loop()
loop.run_until_complete(do_find_one())

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查找多条记录

查找记录可以添加筛选条件。

async def do_find():
    cursor = db.test_collection.find({‘name‘: {‘$lt‘: 5}}).sort(‘i‘)
    for document in await cursor.to_list(length=100):
        pprint.pprint(document)

loop = asyncio.get_event_loop()
loop.run_until_complete(do_find())

# 添加筛选条件，排序、跳过、限制返回结果数
async def do_find():
    cursor = db.test_collection.find({‘name‘: {‘$lt‘: 4}})
    # Modify the query before iterating
    cursor.sort(‘name‘, -1).skip(1).limit(2)
    async for document in cursor:
        pprint.pprint(document)

loop = asyncio.get_event_loop()
loop.run_until_complete(do_find())

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统计

async def do_count():
    n = await db.test_collection.count_documents({})
    print(‘%s documents in collection‘ % n)
    n = await db.test_collection.count_documents({‘name‘: {‘$gt‘: 1000}})
    print(‘%s documents where i > 1000‘ % n)

loop = asyncio.get_event_loop()
loop.run_until_complete(do_count())

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替换

替换则是将除 id 以外的其他内容全部替换掉。

async def do_replace():
    coll = db.test_collection
    old_document = await coll.find_one({‘name‘: ‘zone‘})
    print(‘found document: %s‘ % pprint.pformat(old_document))
    _id = old_document[‘_id‘]
    result = await coll.replace_one({‘_id‘: _id}, {‘sex‘: ‘hanson boy‘})
    print(‘replaced %s document‘ % result.modified_count)
    new_document = await coll.find_one({‘_id‘: _id})
    print(‘document is now %s‘ % pprint.pformat(new_document))

loop = asyncio.get_event_loop()
loop.run_until_complete(do_replace())

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更新

更新指定字段，不会影响到其他内容。

async def do_update():
    coll = db.test_collection
    result = await coll.update_one({‘name‘: 0}, {‘$set‘: {‘sex‘: ‘girl‘}})
    print(‘更新条数： %s ‘ % result.modified_count)
    new_document = await coll.find_one({‘name‘: 0})
    print(‘更新结果为： %s‘ % pprint.pformat(new_document))

loop = asyncio.get_event_loop()
loop.run_until_complete(do_update())

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删除

删除指定记录。

async def do_delete_many():
    coll = db.test_collection
    n = await coll.count_documents({})
    print(‘删除前有 %s 条数据‘ % n)
    result = await db.test_collection.delete_many({‘name‘: {‘$gte‘: 10}})
    print(‘删除后 %s ‘ % (await coll.count_documents({})))

loop = asyncio.get_event_loop()
loop.run_until_complete(do_delete_many())

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后记

MongoDB 的骚操作就介绍到这里，后面会继续写 MySQL 和 Redis 的骚操作。尽请期待。

【转】Python操作MongoDB数据库

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