import pymongo

## 连接数据库

client = pymongo.MongoClient(host='localhost', port=27017)

## 指定数据库 kuluma

db = client.kuluma

## 指定集合

collection = db.mycol

## 插入数据

## insert_one 插入一条数据

student = {

    'id':'190720157',

    'name':'Amy',

    'age':23,

    'gender':'female'

}

result = collection.insert_one(student)

print(result) ## 返回 InsertOneResult 对象

print(result.inserted_id) ## 获取 MonggoDB 自动添加的标识符 _id :5ea5340ef3cd203fa1577e4e

## insert_many 插入多条数据

student1 = {

    'id':'190720158',

    'name':'Lily',

    'age':18,

    'gender':'female'

}

student2 = {

    'id':'190720159',

    'name':'Mark',

    'age':20,

    'gender':'male'

}

results = collection.insert_many([student1,student2])

print(results)

print(results.inserted_ids)

## 查询多条数据

results = collection.find({'age':20})

for r in results:

    print(r)

## 查询 一条数据

result = collection.find_one({'name':'Amy'})

print(type(result)) ## <class 'dict'> 返回结果时字典类型

print(result)

## 查询年龄大于等于20的数据

result1 = collection.find({'age':{'$gte':20}})

for r in result1:

    print(r)

## 正则匹配查询

##查询以 M 开头的学生

result2 = collection.find({'name':{'$regex':'^M.*'}})

for r in result2:

    print(r)

## 计数

count = collection.find().count()

print(count)

## 排序

s_sort = collection.find().sort('age',pymongo.ASCENDING)

print([s for s in s_sort]) ## 升序

j_sort = collection.find().sort('age',pymongo.DESCENDING)

print([j for j in j_sort]) ## 降序

## 偏移 跳过前两个查询结果，得到第三个以后的数据

skip = collection.find().sort('age',pymongo.ASCENDING).skip(2)

print([s['name'] for s in skip])

## limit(1) 限制只返回一个结果

limit= collection.find().sort('age',pymongo.ASCENDING).skip(2).limit(1)

print([l['name'] for l in limit])