Python就业班——MongoDB数据库
1、mongodb命令启动与停止服务
>net start "mongodb server" >net stop "mongodb server"
2、命令行客户端
>mongo --host localhost --port 27017
>use school
>show dbs
>db.student.save({name: "Scott", age: 99, sex: "male", city: "Beijing"})
>show dbs
3、mongoDB内置角色
以下四个角色的权限仅限于某个逻辑库，不能管理其他逻辑库
Read：允许用户读取指定逻辑库
readWrite：允许用户读写指定逻辑库
dbAdmin：可以管理指定的逻辑库
userAdmin：可以管理指定逻辑库的用户
以下四个角色只能创建在admin逻辑库中，可以管理其他逻辑库
readAnyDatabase：允许读取任何逻辑库
readWriteAnyDatabase：允许读写任何逻辑库
dbAdminAnyDatabase：允许管理任何逻辑库
userAdminAnyDatabase：允许管理任何逻辑库用户
以下两个角色必须创建在admin逻辑库，root角色权限最大
clusterAdmin：允许管理MongoDB集群
root：超级管理员，拥有最高权限
4、设置登录帐户
use admin db.createUser({ user: "admin", pwd: "admin", roles: [{role: "root", db: "admin"}), mechanisms: ["SCRAM-SHA-1"] })
5、开启登录验证功能
创建MongoDB配置文件mongo.cnf
dbpath=C:\Program Files\MongoDB\Server\4.0\data
logpath=C:\Program Files\MongoDB\Server\4.0\logs\mongod.log
auth=true
为了让MongoDB服务加载mongoDB.cnf文件，需要重新安装MongoDB服务(PowerShell执行下面命令)
mongod --config "C:\Program Files\MongoDB\Server\4.0\mongoDB.cnf" --reinstall
6、登录MongoDB
use admin db.auth("admin", "admin")
7、操作MongoDB
创建/切换逻辑库：use test
查看逻辑库：show dbs
删除逻辑库：db.dropDatabase()
创建集合：db.createCollection("student")
查看集合：show collections
删除集合：db.student.drop()
查看集合记录数量：db.student.count()
查看数据空间容量：db.student.dataSize()
重命名集合：db.student.renameCollection("stu")
插入数据：
db.student.save([ {name: "AA", age: 18, sex: "male"}, {name: "BB", age: 18, sex: "male"}, {name: "VV", age: 18, sex: "male"}, {name: "CC", age: 18, sex: "male"} ])
时间戳：MongoDB存储日期会自动转换成格林尼治时区
ObjectId("1f5c6ce09080f119f2fd1ce0").getTimestamp()
查询记录：
db.student.find() db.student.find({name: "AA", sex: "male"}) db.student.find({sex: "male", age: {$gte: 20}})
db.student.findOne()
表达式：
| $lt | 小于 |
| $gt | 大于 |
| $lte | 小于等于 |
| $gte | 大于等于 |
| $in | 包括 |
| $nin | 不包括 |
| $ne | 不等于 |
| $all | 全部 |
| $not | 取反 |
| $or | 或关系 |
| $exists | 含有字段 |
use school db.student.find({ age: {$gte: 20, $lte: 38} }) // 插入一条数据 db.teacher.save({name: "Jim", role: ["班主任", "年级主任", "校长"]}) //查询身份是班主任和年级主任的教师 db.teacher.find({role: {$all: ["班主任", "年级主任"]}}) // 查询年龄不在28~30之间的学生 db.student.find({age: {$not: {$gte: 18, $lte: 30}}}) // 查询30岁以下的男学生，或者25岁以下的女学生 db.student.find({ $or: [ {age: {$lt: 30}, sex: "男"}, {age: {$lt: 25}, sex: "女"} ] }) // 查询含有age字段的学生 db.student.find({age: {$exists: 1}})
正则表达式：
db.student.find({name: /^李/})
db.student.find({name: /^[a-zA-Z]{2,10}$/})
分页查询：
db.student.find().limit(20); db.student.find().skip(20).limit(10);
db.student.find({name:/^[a-zA-Z1-9]{2,10}$/}).skip(1).limit(2)
数据排序：(1代表升序，-1代表降序)
db.student.find().sort({name: 1})
db.student.find().sort({name: -1}).skip(10).limit(10)
db.student.find({name:/^[a-zA-Z1-9]{2,10}$/}).sort({name: -1}).skip(1).limit(2)
排除重复：distinct()函数代替find()函数查找不重复的记录
db.student.distinct("name") db.student.distinct("name").sort(function() { return -1 }) db.student.distinct("name").slice(0, 5)
db.student.distinct("name").sort(()=>{return 1}).slice(0, 2)
删除、修改记录：
update：修改符合条件的第一条记录
updateMany：修改符合条件的所有记录
db.collection.update({condition}, {$set: {data}}) db.collection.updateMany({condition}, {$set: {data}})
// 把李强年龄修改成26岁，班级修改为2-6 db.collection.update({name: "李强"}, {$set: {age: 26, classno: "2-6"}})
// 把26岁以上的男同学班级修改为2-6 db.collection.updateMany({sex: "男", age: {$gte: 25}}, {$set: {classno: "2-6"}})
$unset：删除记录中的字段
$inc：对某个字段值都做加法运算
db.student.updateMany({}, {$unset: {city: 1, tel: 1}})
db.student.updateMany({}, {$inc: {age:2}})
$push：向数组属性添加元素
$pull：删除数组属性元素
db.teacher.update({name: "Jim"}, {$push: {role: "教务主任"}}) db.teacher.update({name: "Jim"}, {$pull: {role: "副校长"}})
remove()：删除记录
db.student.remove({}) db.student.remove({class: "6-2", sex: "男"})
创建索引：
db.collection.createIndex({key: 1}, options)
// 1升序，-1降序
db.student.createIndex({name: 1})
// 删除指定索引
db.student.dropIndex("index_name")
// 删除所有索引
db.student.dropIndexes()
// 创建索引会阻塞MongoDB，影响增删改查操作，在参数添加background，让索引在空闲的时候创建；name设置索引名；
db.student.createIndex({name: 1}, {background: true, name: "name"})
// 获取所有索引
db.student.getIndexes()
唯一性索引：只能创建在每个记录都含有的公共字段上，在非公共字段上是不能创建唯一性索引的
// 创建唯一性索引 db.student.createIndex({sid: 1}, {background: true, unique: true, name: "sid_index"})
创建索引的原则：
_1.数据量很大的集合必须创建索引，相反则不需要创建索引
_2.集合的数据读取过多写入，则需要创建索引
_3.给经常被当做查询条件的字段设置索引
————————————————————————————
use school // db.student.save({name:"jack", age: 19}) // db.dropDatabase() // db.createCollection("teacher") // show collections // db.teacher.drop() // db.student.count() // db.student.dataSize() // db.student.renameCollection("stu") // show collections // db.student.save([ // {name: "AA", age: 18, sex: "male"}, // {name: "BB", age: 18, sex: "male"}, // {name: "VV", age: 18, sex: "male"}, // {name: "CC", age: 18, sex: "male"} // ]) // ObjectId("1f5c6ce09080f119f2fd1ce0").getTimestamp() // db.student.find() // db.student.find({name: "BB", sex: "male"}) // db.student.find({sex: "male", age: {$gte: 20}}) /* db.student.find({ age: {$gte: 20, $lte: 38} }) // 插入一条数据 db.teacher.save({name: "Jim", role: ["班主任", "年级主任", "校长"]}) //查询身份是班主任和年级主任的教师 db.teacher.find({role: {$all: ["班主任", "年级主任"]}}) // 查询年龄不在28~30之间的学生 db.student.find({age: {$not: {$gte: 18, $lte: 30}}}) // 查询30岁以下的男学生，或者25岁以下的女学生 db.student.find({ $or: [ {age: {$lt: 30}, sex: "男"}, {age: {$lt: 25}, sex: "女"} ] }) // 查询含有age字段的学生 db.student.find({age: {$exists: 1}}) */ // db.student.find().limit(2) // db.student.find().skip(1).limit(3) // db.student.distinct("sex") // db.student.distinct("sex").sort(()=>{return -1}) // db.student.distinct("sex").slice(0, 1)
8、数据导出导入
_1.mongoexport导出集合数据（csv、json）
mongoexport --host=localhost --port=27017 -u admin -p admin --authenticationDatabase=admin -d school -c student [-f "_id,name,sex,age"] -o D:/student.json
_2.mongoimport导入集合的数据
mongoimport --host=localhost --port=27017 -u admin -p admin --authenticationDatabase=admin -d test -c student --file=D:/student.json
_3.mongodump导出逻辑库的数据
--dumpDbUsersAndRoles参数可以备份隶属于逻辑库的用户
mongodump --host=localhost --port=27017 -u admin -p admin --authenticationDatabase=admin [-d school] -o D:/
_4.mongorestore导入逻辑库数据
--drop删除已有的数据在导入
mongorestore --host=localhost --port=27017 -u admin -p admin -authenticationDatabase=admin [--drop] -d school D:/school
9、安装pymongo
pip install pymongo
10、创建连接、基本操作
MongoClient客户端代理对象用来执行增删改查操作，内置连接池
from pymongo import MongoClient
client = MongoClient(host="localhost", port=27017)
client.admin.authenticate("admin", "admin")
_1. 数据写入：insert_one、insert_many
#!/usr/bin/env python3 # coding=utf-8 # Version:python3.6.1 # Project:pythonMongoDBDemo # File:1、数据写入.py # Data:2020/10/18 14:37 # Author:LGSP_Harold from mongo_db import client client.school.teacher.insert_one({"name": "Jim"}) client.school.teacher.insert_many([ {"name": "Lucifer"}, {"name": "Harold"}, {"name": "Adolph"}, {"name": "Leslie"} ]) if __name__ == '__main__': pass
_2.数据查询：find_one、find
#!/usr/bin/env python3 # coding=utf-8 # Version:python3.6.1 # Project:pythonMongoDBDemo # File:2、数据查询.py # Data:2020/10/18 17:13 # Author:LGSP_Harold from mongo_db import client try: teachers = client.school.teacher.find({}) for one in teachers: print(one["_id"], one["name"]) print("________________") teacher = client.school.teacher.find_one({"name": "Jim", "role": "校长"}) print(teacher["_id"], teacher["name"], teacher["role"]) except Exception as e: print(e) if __name__ == '__main__': pass
_3.数据修改：update_one、update_many
#!/usr/bin/env python3 # coding=utf-8 # Version:python3.6.1 # Project:pythonMongoDBDemo # File:3、数据修改.py # Data:2020/11/9 15:09 # Author:LGSP_Harold from mongo_db import client try: client.school.teacher.update_many({}, {"$set": {"role": ["班主任"]}}) client.school.teacher.update_one({"name": "Harold"}, {"$set": {"sex": "男", "age": 95}}) client.school.teacher.update_one({"name": "Harold", "sex": {"$ne": "男"}}, {"$push": {"role": "校长"}}) except Exception as e: print(e) if __name__ == '__main__': pass
_4.数据删除：delete_one、delete_many
#!/usr/bin/env python3 # coding=utf-8 # Version:python3.6.1 # Project:pythonMongoDBDemo # File:4、数据删除.py # Data:2020/11/9 17:53 # Author:LGSP_Harold from mongo_db import client try: client.school.teacher.delete_one({"name": "Jim"}) client.school.teacher.delete_many({}) except Exception as e: print(e) if __name__ == '__main__': pass
_5.其他操作：skip、limit、count、distinct、sort
#!/usr/bin/env python3 # coding=utf-8 # Version:python3.6.1 # Project:pythonMongoDBDemo # File:5、其他操作.py # Data:2020/11/9 18:02 # Author:LGSP_Harold from mongo_db import client try: students = client.school.student.find({}).skip(0).limit(10) for one in students: print(one) result = client.school.student.distinct("age") for one in result: print(one) students = client.school.student.find({}).sort([("name", -1)]) for one in students: print(one) count = client.school.student.find({}).count() print(count) except Exception as e: print(e) if __name__ == '__main__': pass
11、把文件存放在NoSql数据库：
_1.MongoDB默认存储16M，可在配置文件修改（不建议修改，16M是最经济的存储方案）
_2.GridFS存储引擎，主要用于存储超过16M的文件，对大文件有着更好的性能
Grid FS使用两个集合来存储文件，一个是chunks集合，用来存放文件；另一个集合是files，用于存储文件的元数据（名字、大小、上传时间、自行规定的属性信息等）
Grid FS会把文件分割成若干chunks（256KB），然后在files记录它们
_2.1.默认情况下MongoClient不提供操作GridFS，需要创建GridFS对象
#!/usr/bin/env python3 # coding=utf-8 # Version:python3.6.1 # Project:pythonMongoDBDemo # File:6、GridFS.py # Data:2020/11/9 22:14 # Author:LGSP_Harold from mongo_db import client from gridfs import GridFS db = client.school gfs = GridFS(db, "book") if __name__ == '__main__': pass
_2.2.保存文件
#!/usr/bin/env python3 # coding=utf-8 # Version:python3.6.1 # Project:pythonMongoDBDemo # File:6、GridFS.py # Data:2020/11/9 22:14 # Author:LGSP_Harold from mongo_db import client from gridfs import GridFS db = client.school gfs = GridFS(db, "book") file = open("D:/ProgramFiles/Development/PythonWorkspace/pythonMongoDBDemo/python无师自通.pdf", "rb") args = {"type": "PDF", "keyword": "linux"} gfs.put(file, filename="python无师自通.pdf", **args) file.close() if __name__ == '__main__': pass
_2.3.查询GridFS中存储的文件：find和find_one函数可以查询Grid FS中存储的文件；exists判断是否存储某个文件
#!/usr/bin/env python3 # coding=utf-8 # Version:python3.6.1 # Project:pythonMongoDBDemo # File:7、GridFS查询存储的文件_find_one.py # Data:2020/11/9 22:51 # Author:LGSP_Harold from mongo_db import client from gridfs import GridFS import math db = client.school gfs = GridFS(db, collection="book") book = gfs.find_one({"filename": "python无师自通.pdf"}) print(book.filename) print(book.type) print(book.keyword) print("%dM" % (math.ceil(book.length/1024/1024))) if __name__ == '__main__': pass
#!/usr/bin/env python3 # coding=utf-8 # Version:python3.6.1 # Project:pythonMongoDBDemo # File:8、GridFS查询存储的文件_find.py # Data:2020/11/9 23:53 # Author:LGSP_Harold from datetime import timedelta from mongo_db import client from gridfs import GridFS db = client.school gfs = GridFS(db, "book") books = gfs.find({"type": "PDF"}) for one in books: uploadDate = (one.uploadDate + timedelta(hours=8)).strftime("%Y-%m-%d %H:%M:%S") print(one._id, one.filename, uploadDate) if __name__ == '__main__': pass
#!/usr/bin/env python3 # coding=utf-8 # Version:python3.6.1 # Project:pythonMongoDBDemo # File:9、GridFS判断是否存储了文件.py # Data:2020/11/10 0:52 # Author:LGSP_Harold from mongo_db import client from gridfs import GridFS from bson.objectid import ObjectId db = client.school gfs = GridFS(db, "book") rs = gfs.exists(ObjectId("5fa9534ec58627c971fbfc6a")) print(rs) rs = gfs.exists(**{"filename": "111.html"}) print(rs) if __name__ == '__main__': pass
_2.4.读取文件
#!/usr/bin/env python3 # coding=utf-8 # Version:python3.6.1 # Project:pythonMongoDBDemo # File:10、GridFS读取文件.py # Data:2020/11/10 1:04 # Author:LGSP_Harold from mongo_db import client from gridfs import GridFS from bson.objectid import ObjectId db = client.school gfs = GridFS(db, "book") document = gfs.get(ObjectId("5fa9534ec58627c971fbfc6a")) file = open("D:/ProgramFiles/Development/PythonWorkspace/pythonMongoDBDemo/python无师自通1.pdf", "wb") file.write(document.read()) file.close() if __name__ == '__main__': pass
_2.5.删除文件
#!/usr/bin/env python3 # coding=utf-8 # Version:python3.6.1 # Project:pythonMongoDBDemo # File:11、GridFS删除文件.py # Data:2020/11/10 1:13 # Author:LGSP_Harold from mongo_db import client from gridfs import GridFS from bson.objectid import ObjectId db = client.school gfs = GridFS(db, "book") gfs.delete(ObjectId("5fa9534ec58627c971fbfc6a")) if __name__ == '__main__': pass
P.S.1：pymongo文档：https://api.mongodb.com/python/current/tutorial.html
略懂，略懂....
