MongoDB使用手册
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highlight: MongoDB使用手册
简介：
MongoDB是一个基于分布式文件存储的数据库。由C++语言编写，旨在为WEB应用提供可扩展的高性能数据存储解决方案。MongoDB是一个介于关系型数据库和非关系型数据库之间的产品，是非关系型数据库当中功能最丰富，最像关系型数据库的。
一. 安装
官网点击下载
网盘点击下载
1. 下载MongoDB安装包，选择windows版；
2. 运行MongoDB安装包并选择自定义安装，设置好安装路径（可以选择自定义安装路径）；
3. 配置MongoDB，让MongoDB作为服务运行，配置好数据目录和日志目录；
4. 最终可取消MongoDB Compass的安装选项（不取消安装极慢），需要可自行安装；
5. 双击mongo.exe 即可以运行MongoDB自带客户端，并使用MongoDB：
6. 连接成功后效果如下：
7. 如果需要移除MongoDB服务, 使用管理员权限运行cmd工具, 并输入如下命令结束进程：
> sc.exe delete MongoDB
8. 为了方便可通过网盘下载视图化的客户端工具进行使用。
二. MongoDB的使用
介绍：MongoDB是非关系型数据库当中最像关系型数据库的，所以我们通过它与关系型数据库的对比。
| SQL数据库 | MongoDB数据库 | 概念 |
|---|
| database | database | 数据库 |
| table | collection | 数据表（集合List) |
| row | document | 数据记录行（文档） |
| column | field | 数据字段（域） |
| index | index | 索引 |
| primary key | primary key | 主键,MongoDB自动将_id字段设置为主键 |
1. 创建库 use database_name 如果database_name数据库存在便进入该数据库中，如果不存在创建该数据库并进入数据库中。
> use database_name
switched to db database_name
2. 删除库 dropDatabase() 来删除（删除需慎重）
删除前：
> show dbs
admin 0.000GB
config 0.000GB
local 0.000GB
mysql 0.000GB
test 0.000GB
删除：
> use mysql
switched to db mysql
> db
mysql
> db.dropDatabase()
{ "dropped" : "mysql", "ok" : 1 }
删除后：
> show dbs
admin 0.000GB
config 0.000GB
local 0.000GB
test 0.000GB
3. 创建集合（sql中表的概念）db.createCollection()
> use dbtest
switched to db dbtest
> show tables
> db.createCollection('a1')
{ "ok" : 1 }
> show tables
a1
4. 删除集合（sql中表的概念）db.tables_name.drop()
> show tables
a1
> db.a1.drop()
true
> show tables
>
5. 插入文档document - sql新增记录行 db.table_name.insert(document)
> db
dbtest
> db.a1.find()
{ "_id" : ObjectId("5fd092ffc0996d1ec790c72a") }
> db.a1.insert({'username':'xiaoming','age':19,'password':'123','create_time':'2020-12-09 17:00:00'})
WriteResult({ "nInserted" : 1 })
> db.a1.find()
{ "_id" : ObjectId("5fd092ffc0996d1ec790c72a") }
{ "_id" : ObjectId("5fd09590c0996d1ec790c72c"), "username" : "xiaoming", "age" : 19, "password" : "123", "create_time" : "2020-12-09 17:00:00" }
6. 更新文档 - 更新数据记录行
db.collection.update(<query>,<update>,{multi: <boolean>})
# query：修改的查询条件，类似于SQL中的WHERE部分
# update：更新属性的操作符，类似与SQL中的SET部分
# multi：设置为true时会更新所有符合条件的文档，默认为false只更新找到的第一条
> db
dbtest
> db.a1.find()
{ "_id" : ObjectId("5fd092ffc0996d1ec790c72a") }
> db.a1.insert({'username':'xiaoming','age':19,'password':'123','create_time':'2020-12-09 17:00:00'})
WriteResult({ "nInserted" : 1 })
> db.a1.find()
{ "_id" : ObjectId("5fd092ffc0996d1ec790c72a") }
{ "_id" : ObjectId("5fd09590c0996d1ec790c72c"), "username" : "xiaoming", "age" : 19, "password" : "123", "create_time" : "2020-12-09 17:00:00" }
> db.a1.update({'username':'xiaoming'},{$set:{'age':20}},{multi:true})
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> db.a1.find()
{ "_id" : ObjectId("5fd092ffc0996d1ec790c72a") }
{ "_id" : ObjectId("5fd09590c0996d1ec790c72c"), "username" : "xiaoming", "age" : 20, "password" : "123", "create_time" : "2020-12-09 17:00:00" }
>
7. 删除文档 - 删除数据记录行 remove（）
db.collection.remove(<query>,{justOne: <boolean>})
# query：删除的查询条件，类似于SQL中的WHERE部分
# justOne：设置为true只删除一条记录，默认为false删除所有记录
> db.a1.find()
{ "_id" : ObjectId("5fd092ffc0996d1ec790c72a") }
{ "_id" : ObjectId("5fd09590c0996d1ec790c72c"), "username" : "xiaoming", "age" : 20, "password" : "123", "create_time" : "2020-12-09 17:00:00" }
{ "_id" : ObjectId("5fd09b0b7cb5fe86451090bc"), "username" : "xiaoming", "age" : 19, "password" : "123", "create_time" : "2020-12-09 17:00:00" }
> db.a1.remove({'username':'xiaoming'},{justOne:true})
WriteResult({ "nRemoved" : 1 })
> db.a1.find()
{ "_id" : ObjectId("5fd092ffc0996d1ec790c72a") }
{ "_id" : ObjectId("5fd09b0b7cb5fe86451090bc"), "username" : "xiaoming", "age" : 19, "password" : "123", "create_time" : "2020-12-09 17:00:00" }
>
8. 通过collection对象的find()方法来查询文档
| mongo符号 | 含义 | mongo格式 | SQL语句 |
|---|
| : | 等于 | {:} | where a = 'b' |
| $lt | 小于 | {:{$lt:}} | where a < 10 |
| $gt | 大于 | {:{$gt:}} | where a > 20 |
| $lte | 小于等于 | {:{$lte:}} | where a <= 10 |
| $gte | 大于等于 | {:{$gte:}} | where a >= 20 |
| $ne | 不等于 | {:{$ne:}} | where a != 30 |
db.collection.find(query, projection)
# query：查询条件，类似于SQL中的WHERE部分
# projection：可选，使用投影操作符指定返回的键
> db.a1.find()
{ "_id" : ObjectId("5fd092ffc0996d1ec790c72a") }
{ "_id" : ObjectId("5fd09b0b7cb5fe86451090bc"), "username" : "xiaoming", "age" : 19, "password" : "123", "create_time" : "2020-12-09 17:00:00" }
{ "_id" : ObjectId("5fd09c8c7cb5fe86451090bd"), "username" : "xiaoming", "age" : 22, "password" : "1234", "create_time" : "2020-12-09 17:00:00" }
{ "_id" : ObjectId("5fd09c967cb5fe86451090be"), "username" : "xiaoming", "age" : 343, "password" : "1234", "create_time" : "2020-12-09 17:00:00" }
# 按条件查询 -- 等于
> db.a1.find({'age':22})
{ "_id" : ObjectId("5fd09c8c7cb5fe86451090bd"), "username" : "xiaoming", "age" : 22, "password" : "1234", "create_time" : "2020-12-09 17:00:00" }
# 按条件查询 -- 小于
> db.a1.find({'age':{$lt:20}})
{ "_id" : ObjectId("5fd09b0b7cb5fe86451090bc"), "username" : "xiaoming", "age" : 19, "password" : "123", "create_time" : "2020-12-09 17:00:00" }
# 按条件查询 -- 小于等于
> db.a1.find({'age':{$lte:19}})
{ "_id" : ObjectId("5fd09b0b7cb5fe86451090bc"), "username" : "xiaoming", "age" : 19, "password" : "123", "create_time" : "2020-12-09 17:00:00" }
# 按条件查询 -- 大于
> db.a1.find({'age':{$gt:19}})
{ "_id" : ObjectId("5fd09c8c7cb5fe86451090bd"), "username" : "xiaoming", "age" : 22, "password" : "1234", "create_time" : "2020-12-09 17:00:00" }
{ "_id" : ObjectId("5fd09c967cb5fe86451090be"), "username" : "xiaoming", "age" : 343, "password" : "1234", "create_time" : "2020-12-09 17:00:00" }
# 按条件查询 -- 大于等于
> db.a1.find({'age':{$gte:343}})
{ "_id" : ObjectId("5fd09c967cb5fe86451090be"), "username" : "xiaoming", "age" : 343, "password" : "1234", "create_time" : "2020-12-09 17:00:00" }
# 按条件查询 -- 不等于
> db.a1.find({'age':{$ne:343}})
{ "_id" : ObjectId("5fd092ffc0996d1ec790c72a") }
{ "_id" : ObjectId("5fd09b0b7cb5fe86451090bc"), "username" : "xiaoming", "age" : 19, "password" : "123", "create_time" : "2020-12-09 17:00:00" }
{ "_id" : ObjectId("5fd09c8c7cb5fe86451090bd"), "username" : "xiaoming", "age" : 22, "password" : "1234", "create_time" : "2020-12-09 17:00:00" }
# 按条件查询 -- and
> db.a1.find({'age':{$ne:343},'username':'xiaoming'})
{ "_id" : ObjectId("5fd09b0b7cb5fe86451090bc"), "username" : "xiaoming", "age" : 19, "password" : "123", "create_time" : "2020-12-09 17:00:00" }
{ "_id" : ObjectId("5fd09c8c7cb5fe86451090bd"), "username" : "xiaoming", "age" : 22, "password" : "1234", "create_time" : "2020-12-09 17:00:00" }
> db.a1.find({'age':{$ne:343},'username':'xiaoming1'})
>
# 按条件查询 -- or
> db.a1.find({$or:[{'age':{$ne:343}},{'username':'xiaoming'}]})
{ "_id" : ObjectId("5fd092ffc0996d1ec790c72a") }
{ "_id" : ObjectId("5fd09b0b7cb5fe86451090bc"), "username" : "xiaoming", "age" : 19, "password" : "123", "create_time" : "2020-12-09 17:00:00" }
{ "_id" : ObjectId("5fd09c8c7cb5fe86451090bd"), "username" : "xiaoming", "age" : 22, "password" : "1234", "create_time" : "2020-12-09 17:00:00" }
{ "_id" : ObjectId("5fd09c967cb5fe86451090be"), "username" : "xiaoming", "age" : 343, "password" : "1234", "create_time" : "2020-12-09 17:00:00" }
# 按条件查询 -- and+or
> db.a1.find({'age':{$lt:22}},{$or:[{'age':{$ne:343}},{'username':'xiaoming'}]})
{ "_id" : ObjectId("5fd09b0b7cb5fe86451090bc") }
> db.a1.find({'age':{$gt:22}},{$or:[{'age':{$ne:343}},{'username':'xiaoming'}]})
{ "_id" : ObjectId("5fd09c967cb5fe86451090be") }
9. 其他操作
limit（指定长度数据）与skip（跳过某些数量）
> db.a1.find().limit(2)
{ "_id" : ObjectId("5fd092ffc0996d1ec790c72a") }
{ "_id" : ObjectId("5fd09b0b7cb5fe86451090bc"), "username" : "xiaoming", "age" : 19, "password" : "123", "create_time" : "2020-12-09 17:00:00" }
> db.a1.find().limit(3).skip(2)
{ "_id" : ObjectId("5fd09c8c7cb5fe86451090bd"), "username" : "xiaoming", "age" : 22, "password" : "1234", "create_time" : "2020-12-09 17:00:00" }
{ "_id" : ObjectId("5fd09c967cb5fe86451090be"), "username" : "xiaoming", "age" : 343, "password" : "1234", "create_time" : "2020-12-09 17:00:00" }
> db.a1.find().limit(3).skip(1)
{ "_id" : ObjectId("5fd09b0b7cb5fe86451090bc"), "username" : "xiaoming", "age" : 19, "password" : "123", "create_time" : "2020-12-09 17:00:00" }
{ "_id" : ObjectId("5fd09c8c7cb5fe86451090bd"), "username" : "xiaoming", "age" : 22, "password" : "1234", "create_time" : "2020-12-09 17:00:00" }
{ "_id" : ObjectId("5fd09c967cb5fe86451090be"), "username" : "xiaoming", "age" : 343, "password" : "1234", "create_time" : "2020-12-09 17:00:00" }
sort（排序）升序 1，降序 -1
# 升序
db.a1.find().sort({'age':1})
{ "_id" : ObjectId("5fd092ffc0996d1ec790c72a") }
{ "_id" : ObjectId("5fd09b0b7cb5fe86451090bc"), "username" : "xiaoming", "age" : 19, "password" : "123", "create_time" : "2020-12-09 17:00:00" }
{ "_id" : ObjectId("5fd09c8c7cb5fe86451090bd"), "username" : "xiaoming", "age" : 22, "password" : "1234", "create_time" : "2020-12-09 17:00:00" }
{ "_id" : ObjectId("5fd09c967cb5fe86451090be"), "username" : "xiaoming", "age" : 343, "password" : "1234", "create_time" : "2020-12-09 17:00:00" }
# 降序
> db.a1.find().sort({'age':-1})
{ "_id" : ObjectId("5fd09c967cb5fe86451090be"), "username" : "xiaoming", "age" : 343, "password" : "1234", "create_time" : "2020-12-09 17:00:00" }
{ "_id" : ObjectId("5fd09c8c7cb5fe86451090bd"), "username" : "xiaoming", "age" : 22, "password" : "1234", "create_time" : "2020-12-09 17:00:00" }
{ "_id" : ObjectId("5fd09b0b7cb5fe86451090bc"), "username" : "xiaoming", "age" : 19, "password" : "123", "create_time" : "2020-12-09 17:00:00" }
{ "_id" : ObjectId("5fd092ffc0996d1ec790c72a") }
索引 createIndex()
db.collection.createIndex(keys, options)
# background：建索引过程会阻塞其它数据库操作，设置为true表示后台创建，默认为false
# unique：设置为true表示创建唯一索引
# name：指定索引名称，如果没有指定会自动生成
# {'age':1} 1 ：升序； -1 ：降序
# 普通索引
> db.a1.createIndex({'age':1},{background:true})
{
"createdCollectionAutomatically" : false,
"numIndexesBefore" : 1,
"numIndexesAfter" : 2,
"ok" : 1
}
# 唯一索引
> db.a1.createIndex({'_id':1},{unique:true})
{
"ok" : 0,
"errmsg" : "The field 'unique' is not valid for an _id index specification. Specification: { ns: \"dbtest.a1\", v: 2, key: { _id: 1.0 }, name: \"_id_1\", unique: true }",
"code" : 197,
"codeName" : "InvalidIndexSpecificationOption"
}
# 查看索引
> db.a1.getIndexes()
[
{
"v" : 2,
"key" : {
"_id" : 1
},
"name" : "_id_",
"ns" : "dbtest.a1"
},
{
"v" : 2,
"key" : {
"age" : 1
},
"name" : "age_1",
"ns" : "dbtest.a1",
"background" : true
}
]
10. 聚合函数
| 操作符 | 描述 |
|---|
| $sum | 计算总和 |
| $avg | 计算平均值 |
| $min | 计算最小值 |
| $max | 计算最大值 |
# 计算总和
> db.a1.aggregate([{$group : {_id : "$by", sum_count : {$sum : 1}}}])
{ "_id" : null, "sum_count" : 4 }
# 计算平均值
> db.a1.aggregate([{$group : {_id : "$by", avg_age : {$avg : "$age"}}}])
{ "_id" : null, "avg_age" : 128 }
11. 正则表达式
# 不区分大小写的模糊查询，使用$options操作符
db.a1.find({title:{$regex:"elasticsearch",$options:"$i"}})
