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Python编程:mongodb的基本增删改查操作

发布时间:2021-11-23 点击数:102
# -*- coding: utf-8 -*-  # @File    : pymongo_demo.py # @Date    : 2018-06-02 # @Author  : Peng Shiyu  import pymongo

1、创建MongoDB的连接对象

# client = pymongo.MongoClient(host="localhost", port=27017) client = pymongo.MongoClient('mongodb://localhost:27017/')

2、指定数据库

# db = client["mydemo"] db = client.mydemo

3、指定集合Collection对象

# collection = db["students"] collection = db.students

4、插入数据

# 一条数据 student = {  'id': '20170101',  'name': '小明',  'age': 22,  'gender': '男性' }  # result = collection.insert(student) result = collection.insert_one(student) print(result)  # <pymongo.results.InsertOneResult object at 0x1034e08c8> print(result.inserted_id)  # 5b1205b2d7696c4230dd9456  # 多条数据 student1 = {  'id': '20170101',  'name': 'Jordan',  'age': 20,  'gender': 'male' }  student2 = {  'id': '20170202',  'name': 'Mike',  'age': 21,  'gender': 'male' } # # # result = collection.insert([student1, student2]) result = collection.insert_many([student1, student2]) print(result)  # <pymongo.results.InsertManyResult object at 0x1034e0748> print(result.inserted_ids) # # [ObjectId('5b1205b2d7696c4230dd9457'), ObjectId('5b1205b2d7696c4230dd9458')]

5、查询数据库

# 查询一条数据 result = collection.find_one({"name": "Mike"}) print(type(result))  # <class 'dict'> print(result) # {'_id': ObjectId('5b1204a3d7696c41c083d21e'), # 'id': '20170202', 'name': 'Mike', 'age': 21, 'gender': 'male'}  # 通过_id属性来查询, 不存在则返回None from bson.objectid import ObjectId result = collection.find_one({'_id': ObjectId('5b1204a3d7696c41c083d21e')}) print(result) # {'_id': ObjectId('5b1204a3d7696c41c083d21e'), # 'id': '20170202', 'name': 'Mike', 'age': 21, 'gender': 'male'}  # 查询多条数据, 返回一个生成器 results = collection.find({"age": 21}) print(results)  # <pymongo.cursor.Cursor object at 0x10133f160> for result in results:  print(result) # {'_id': ObjectId('5b12055fd7696c4208deb74a'), # 'id': '20170202', 'name': 'Mike', 'age': 21, 'gender': 'male'}  # 条件查询 results = collection.find({"age": {"$gt": 20}}) for result in results:  print(result) # {'_id': ObjectId('5b1209ccd7696c437c51d5bb'), # 'id': '20170101', 'name': '小明', 'age': 22, 'gender': '男性'} # {'_id': ObjectId('5b1209ccd7696c437c51d5bd'), # 'id': '20170202', 'name': 'Mike', 'age': 21, 'gender': 'male'}   # 正则匹配查询 results = collection.find({"name": {"$regex": "^M.*"}}) for result in results:  print(result) # {'_id': ObjectId('5b1209ccd7696c437c51d5bd'), # 'id': '20170202', 'name': 'Mike', 'age': 21, 'gender': 'male'}  ## 转为list >>> db.collection.find() <pymongo.cursor.Cursor object at 0x108dabf50>  >>> list(db.collection.find()) [  {'_id': ObjectId('5839b12eee86fb71849a0905'), 'name': 'Tom'} ] 

比较符号

符号

表示

含义

示例

:

=

等于

{“age”: 20}

$lt

<

小于

{“age”: {"$lt": 20}}

$gt

>

大于

{“age”: {"$gt": 20}}

$lte

<=

小于等于

{“age”: {"$lte": 20}}

$gte

>=

大于等于

{“age”: {"$gte": 20}}

$ne

!=

不等于

{“age”: {"$ne": 20}}

$in

in

范围内

{“age”: {"$in": [20, 30]}}

$nin

not in

不在范围内

{“age”: {"$nin": [20, 30]}}

 

 

 



说明:

lt: less than

gt: great than

e: equal

功能符号

符号

含义

示例

示例说明

$regex

匹配正则表达式

{“name”: {"$regex": “^M.*”}}

name以M开头

$exists

属性是否存在

{“name”: {"$exists": True}}

name属性存在

$type

类型判断

{“age”: {"$type": “int”}}

age的类型为int

$mod

数字模操作

{“age”: {"$mod": [5, 0]}}

年龄模5余0

$text

文本查询

{“text”: {"$search": “Mike”}}

text类型的属性中包含字符串Mike

$where

高级条件查询

{“name”: {"$where": “obj.age==obj.count”}}

自身年龄等于自身数量



6、查询计数

count = collection.find().count() print(count)  # 3

7、数据排序

# 升序pymongo.ASCENDING 降序pymongo.DESCENDING results = collection.find().sort("name", pymongo.ASCENDING) print([result["name"] for result in results]) # ['Jordan', 'Mike', '小明']

8、数据的偏移

results = collection.find().sort('name', pymongo.ASCENDING).skip(2) print([result['name'] for result in results]) # ['小明']  results = collection.find().sort('name', pymongo.ASCENDING).skip(1).limit(1) print([result['name'] for result in results]) # ['Mike']  # 数据库数量非常庞大的时候,不要使用大的偏移量 from bson.objectid import ObjectId results = collection.find({'_id': {'$gt': ObjectId('5b1209ccd7696c437c51d5bb')}}) print([result['name'] for result in results])

9、更新数据库

更新函数

update_one(filter, update, upsert=False, bypass_document_validation=False, collation=None, array_filters=None, session=None)  update_many(filter, update, upsert=False, array_filters=None, bypass_document_validation=False, collation=None, session=None)  # 过时了 update(spec, document, upsert=False, manipulate=False, multi=False, check_keys=True, **kwargs)
condition = {'name': 'Mike'} student = collection.find_one(condition) student['age'] = 25 # 全部用student字典替换 # result = collection.update(condition, student) # 只更新student字典内存在的字段 result = collection.update(condition, {'$set': student}) print(result) # {'n': 1, 'nModified': 1, 'ok': 1.0, 'updatedExisting': True}  condition = {'name': 'Mike'} student = collection.find_one(condition) student['age'] = 26 result = collection.update_one(condition, {'$set': student}) print(result) # <pymongo.results.UpdateResult object at 0x1034de708>  print(result.matched_count, result.modified_count) # 1 1  condition = {'age': {'$gt': 20}} result = collection.update_one(condition, {'$inc': {'age': 1}}) print(result) # <pymongo.results.UpdateResult object at 0x1034e8588> print(result.matched_count, result.modified_count) # 1 1 

10、数据删除

result = collection.remove({'name': 'Jordan'}) print(result)  # 删除一条 result = collection.delete_one({'name': 'Kevin'}) print(result) print(result.deleted_count) result = collection.delete_many({'age': {'$lt': 25}}) print(result.deleted_count)  # 删除多条 result = collection.delete_many({'name': 'Kevin'})

官方文档:

http://api.mongodb.com/python/current/api/pymongo/collection.html

多条件查询

db.getCollection('table').find({"$and": [{"detail": {"$ne": null}}, {"detail": {"$ne": true}}]})