MongoDB 基本操作
当前文档基于 MongoDB server version: 4.0.20
0. MongoDB 特性
用MySQL 和 MongoDB 做比较
| Database | Database | 数据库 |
|---|---|---|
| Table | Collection/Table | 表/集合 |
| MySQL | MongoDB | 说明 |
| Row | Document | 行/文档 |
| Column | Field | 字段/域 |
1. 数据库操作
在mongoDB中, 若数据库不存在，那么只有在库中向集合插入数据的时候才会创建
1.1 用法
查看数据库
show dbs
指定数据库
use Database
查看当前数据库
默认情况下，当前数据库是test
db
删除数据库
在操作此步骤之前，应当使用 db 确认一下库名
执行dropDatabase() 操作后，当前选择的数据库依然是这个库，只不过是在内存中而已。
db.dropDatabase()
查看数据库版本
db.version()
查看当前库统计信息
db.stats()
1.2 例子
查看当前有哪些数据库
> show dbs
admin 0.000GB
blogSystem 0.000GB
config 0.000GB
local 0.000GB
>
查看当前数据库
> db
test
>
创建一个数据库并且查看
> use LearnDB
switched to db LearnDB
>
> db
LearnDB
>
删除数据库
> db.dropDatabase()
{ "ok" : 1 }
>
查看数据库版本
> db.version()
4.0.20
>
查看当前库统计信息
> db.stats()
{
"db" : "LearnDB",
"collections" : 0,
"views" : 0,
"objects" : 0,
"avgObjSize" : 0,
"dataSize" : 0,
"storageSize" : 0,
"numExtents" : 0,
"indexes" : 0,
"indexSize" : 0,
"fileSize" : 0,
"fsUsedSize" : 0,
"fsTotalSize" : 0,
"ok" : 1
}
>
2. 集合操作
默认情况下，mongo在插入文档的时候，集合默认会被创建
2.1 用法
查看当前库的集合
show collections
插入单条数据
db.CollectionName.insertOne()
插入多条数据
db.CollectionName.insertMany()
删除集合
db.CollectionName.drop()
修改集合名称
db.CollectionName.renameCollection()
创建集合
db.createCollection()
2.2 例子
插入单条数据
> db.stu_info.insertOne({"std_name":"小明","sex":"男","reg_time":Date()})
{
"acknowledged" : true,
"insertedId" : ObjectId("61d6b4afa5a7b57ea8e0a9db")
}
查看当前库的集合
> show collections
stu_info
>
插入多条数据
> db.stu_info.insertMany([{"std_name":"小刚","sex":"男","reg_time":Date()},{"std_name":"小红","sex":"女","reg_time":Date()}])
{
"acknowledged" : true,
"insertedIds" : [
ObjectId("61d6b59da5a7b57ea8e0a9dc"),
ObjectId("61d6b59da5a7b57ea8e0a9dd")
]
}
>
删除集合
> db.stu_info.drop()
true
>
修改集合名称
> db.stu_info.renameCollection("stuInfo")
{ "ok" : 1 }
> show collections
stuInfo
>
创建集合
默认情况下，向集合中插入数据，会默认创建，还有一种情况，是设置集合为 容量上限模式 ，则需要提前创建
语法
db.createCollection(<name>, { capped: <boolean>,
autoIndexId: <boolean>,
size: <number>,
max: <number>,
storageEngine: <document>,
validator: <document>,
validationLevel: <string>,
validationAction: <string>,
indexOptionDefaults: <document>,
viewOn: <string>,
pipeline: <pipeline>,
collation: <document>,
writeConcern: <document>} )
name: 集合名称
capped: 若为true,则创建 有上限模式 的集合
size: 设置上限的最大大小，以字节为单位，若达到最大值，则会删除旧文档
max: 允许最大文档数，当同时设置 size 和 max ， 则 size 优先级 大于 max
创建有上限的集合, 允许的条数为5条, 最大容量为1G
> db.createCollection("std_log",{"capped":true , "size": 1073741824 , "max": 5})
{ "ok" : 1 }
>
测试插入数据
可以发现，插入超过5条后，新插入的数据，会删除旧文档，然后插入新文档
> db.std_log.insertMany([{"id":1,"status":true,"time":Date()},{"id":2,"status":false,"time":Date()},{"id":3,"status":true,"time":Date()},{"id":4,"status":true,"time":Date()},{"id":5,"status":false,"time":Date()}])
{
"acknowledged" : true,
"insertedIds" : [
ObjectId("61d6c44da5a7b57ea8e0aa01"),
ObjectId("61d6c44da5a7b57ea8e0aa02"),
ObjectId("61d6c44da5a7b57ea8e0aa03"),
ObjectId("61d6c44da5a7b57ea8e0aa04"),
ObjectId("61d6c44da5a7b57ea8e0aa05")
]
}
> db.std_log.find()
{ "_id" : ObjectId("61d6c44da5a7b57ea8e0aa01"), "id" : 1, "status" : true, "time" : "Thu Jan 06 2022 18:28:29 GMT+0800 (CST)" }
{ "_id" : ObjectId("61d6c44da5a7b57ea8e0aa02"), "id" : 2, "status" : false, "time" : "Thu Jan 06 2022 18:28:29 GMT+0800 (CST)" }
{ "_id" : ObjectId("61d6c44da5a7b57ea8e0aa03"), "id" : 3, "status" : true, "time" : "Thu Jan 06 2022 18:28:29 GMT+0800 (CST)" }
{ "_id" : ObjectId("61d6c44da5a7b57ea8e0aa04"), "id" : 4, "status" : true, "time" : "Thu Jan 06 2022 18:28:29 GMT+0800 (CST)" }
{ "_id" : ObjectId("61d6c44da5a7b57ea8e0aa05"), "id" : 5, "status" : false, "time" : "Thu Jan 06 2022 18:28:29 GMT+0800 (CST)" }
>
> db.std_log.insertOne({"id":6,"status":false,"time":Date()})
{
"acknowledged" : true,
"insertedId" : ObjectId("61d6c4b9a5a7b57ea8e0aa07")
}
> db.std_log.find()
{ "_id" : ObjectId("61d6c44da5a7b57ea8e0aa02"), "id" : 2, "status" : false, "time" : "Thu Jan 06 2022 18:28:29 GMT+0800 (CST)" }
{ "_id" : ObjectId("61d6c44da5a7b57ea8e0aa03"), "id" : 3, "status" : true, "time" : "Thu Jan 06 2022 18:28:29 GMT+0800 (CST)" }
{ "_id" : ObjectId("61d6c44da5a7b57ea8e0aa04"), "id" : 4, "status" : true, "time" : "Thu Jan 06 2022 18:28:29 GMT+0800 (CST)" }
{ "_id" : ObjectId("61d6c44da5a7b57ea8e0aa05"), "id" : 5, "status" : false, "time" : "Thu Jan 06 2022 18:28:29 GMT+0800 (CST)" }
{ "_id" : ObjectId("61d6c4b9a5a7b57ea8e0aa07"), "id" : 6, "status" : false, "time" : "Thu Jan 06 2022 18:30:17 GMT+0800 (CST)" }
>
3. 查询操作
3.1 用法
查询集合文档条数
db.CollectionNmae.count()
普通查询
db.CollectionName.find()
格式化显示
db.CollectionName.find().pretty()
比较查询
等于
db.CollectionName.find({k:v})
不等于
db.CollectionName.find({k:{$ne: v})
大于
db.CollectionName.find({k:{$gt: v})
小于
db.CollectionName.find({k:{$lt: v})
大于或等于
db.CollectionName.find({k:{$lte: v})
小于或等于
db.CollectionName.find({k:{$gte: v})
and | or 查询
and
db.CollectionName.find({k:v,k1:v1})
or
db.CollectionName.find({$or:[{k1:v1},{k2:v2}]})
and 和 or 联合查询
db.CollectionName.find({k:v,$or:[{k1:v1},{k2:v2}]})
排序查询
db.CollectionName.find().sort({k:1})
指定返回行数查询
db.CollectionName.find().limit()
db.CollectionName.find().skip()
指定返回域
db.CollectionName.find({k:v},{k1:1,k2:1})
只返回一条
db.CollectionName.findOne({k:v})
只返回一条并且删除该数据
db.CollectionName.findOneAndDelete({k:v})
3.2 例子
数据准备
> use LearnDB
switched to db LearnDB
>
> db.dropDatabase()
{ "dropped" : "LearnDB", "ok" : 1 }
>
>
> db.stu_info.insertMany([
... {"name": "小明" , "sex": "男" , "score1": 98 , "score2": 60, "score3": 79 , "score5": 101 , "classID: " : 1},
... {"name": "小红" , "sex": "女" , "score1": 100 , "score2": 100, "score3": 100 , "score5": 80 , "classID: " : 3},
... {"name": "小赵" , "sex": "女" , "score1": 80 , "score2": 79, "score3": 33 , "score5": 55 , "classID: " : 3},
... {"name": "小钱" , "sex": "男" , "score1": 89 , "score2": 36, "score3": 102 , "score5": 65 , "classID: " : 5},
... {"name": "小李" , "sex": "女" , "score1": 53 , "score2": 91, "score3": 34 , "score5": 19 , "classID: " : 9},
... {"name": "小王" , "sex": "女" , "score1": 100 , "score2": 100, "score3": 100 , "score5": 99 , "classID: " : 1},
... {"name": "小周" , "sex": "女" , "score1": 99 , "score2": 94, "score3": 92 , "score5": 90 , "classID: " : 6}
... ])
{
"acknowledged" : true,
"insertedIds" : [
ObjectId("61d6cac2a5a7b57ea8e0aa08"),
ObjectId("61d6cac2a5a7b57ea8e0aa09"),
ObjectId("61d6cac2a5a7b57ea8e0aa0a"),
ObjectId("61d6cac2a5a7b57ea8e0aa0b"),
ObjectId("61d6cac2a5a7b57ea8e0aa0c"),
ObjectId("61d6cac2a5a7b57ea8e0aa0d"),
ObjectId("61d6cac2a5a7b57ea8e0aa0e")
]
}
>
查询集合文档条数
> db.stu_info.count()
7
>
普通查询
mongo shell 默认只返回10条，超过10条 需要 根据提示往下翻页
> db.stu_info.find()
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa08"), "name" : "小明", "sex" : "男", "score1" : 98, "score2" : 60, "score3" : 79, "score5" : 101, "classID: " : 1 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa09"), "name" : "小红", "sex" : "女", "score1" : 100, "score2" : 100, "score3" : 100, "score5" : 80, "classID: " : 3 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0a"), "name" : "小赵", "sex" : "女", "score1" : 80, "score2" : 79, "score3" : 33, "score5" : 55, "classID: " : 3 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0b"), "name" : "小钱", "sex" : "男", "score1" : 89, "score2" : 36, "score3" : 102, "score5" : 65, "classID: " : 5 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0c"), "name" : "小李", "sex" : "女", "score1" : 53, "score2" : 91, "score3" : 34, "score5" : 19, "classID: " : 9 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0d"), "name" : "小王", "sex" : "女", "score1" : 100, "score2" : 100, "score3" : 100, "score5" : 99, "classID: " : 1 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0e"), "name" : "小周", "sex" : "女", "score1" : 99, "score2" : 94, "score3" : 92, "score5" : 90, "classID: " : 6 }
>
指定返回行数查询
查询2个文档
> db.stu_info.find().limit(2)
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa08"), "name" : "小明", "sex" : "男", "score1" : 98, "score2" : 60, "score3" : 79, "score5" : 101, "classID: " : 1 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa09"), "name" : "小红", "sex" : "女", "score1" : 100, "score2" : 100, "score3" : 100, "score5" : 80, "classID: " : 3 }
>
跳过第1个文档，查询1个文档
> db.stu_info.find().skip(1).limit(1)
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa09"), "name" : "小红", "sex" : "女", "score1" : 100, "score2" : 100, "score3" : 100, "score5" : 80, "classID: " : 3 }
>
格式化显示
> db.stu_info.find().pretty().limit(2)
{
"_id" : ObjectId("61d6cac2a5a7b57ea8e0aa08"),
"name" : "小明",
"sex" : "男",
"score1" : 98,
"score2" : 60,
"score3" : 79,
"score5" : 101,
"classID: " : 1
}
{
"_id" : ObjectId("61d6cac2a5a7b57ea8e0aa09"),
"name" : "小红",
"sex" : "女",
"score1" : 100,
"score2" : 100,
"score3" : 100,
"score5" : 80,
"classID: " : 3
}
>
比较查询
等于： 查询 name 等于 小明 的文档
> db.stu_info.find({"name":"小明"})
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa08"), "name" : "小明", "sex" : "男", "score1" : 98, "score2" : 60, "score3" : 79, "score5" : 101, "classID: " : 1 }
>
不等于： 查询 name 不等于 小明 的文档，并且取出第一个
> db.stu_info.find({"name":{$ne:"小明"}}).limit(1).pretty()
{
"_id" : ObjectId("61d6cac2a5a7b57ea8e0aa09"),
"name" : "小红",
"sex" : "女",
"score1" : 100,
"score2" : 100,
"score3" : 100,
"score5" : 80,
"classID: " : 3
}
>
大于: 查询 socre3 大于100 的文档
> db.stu_info.find({"score3":{$gt:100}})
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0b"), "name" : "小钱", "sex" : "男", "score1" : 89, "score2" : 36, "score3" : 102, "score5" : 65, "classID: " : 5 }
>
小于: 查询 socre1 小于80 的文档
> db.stu_info.find({"score1":{$lt:80}})
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0c"), "name" : "小李", "sex" : "女", "score1" : 53, "score2" : 91, "score3" : 34, "score5" : 19, "classID: " : 9 }
>
大于或等于：查询 socre3 大于等于 100 的文档
> db.stu_info.find({"score3":{$gte:100}})
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa09"), "name" : "小红", "sex" : "女", "score1" : 100, "score2" : 100, "score3" : 100, "score5" : 80, "classID: " : 3 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0b"), "name" : "小钱", "sex" : "男", "score1" : 89, "score2" : 36, "score3" : 102, "score5" : 65, "classID: " : 5 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0d"), "name" : "小王", "sex" : "女", "score1" : 100, "score2" : 100, "score3" : 100, "score5" : 99, "classID: " : 1 }
>
大于或等于：查询 socre1 小于等于 80 的文档
> db.stu_info.find({"score1":{$lte:80}})
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0a"), "name" : "小赵", "sex" : "女", "score1" : 80, "score2" : 79, "score3" : 33, "score5" : 55, "classID: " : 3 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0c"), "name" : "小李", "sex" : "女", "score1" : 53, "score2" : 91, "score3" : 34, "score5" : 19, "classID: " : 9 }
>
and | or 查询
and：查询 score1等于100 score2等于100 的文档
> db.stu_info.find({"score1":100,"score2":100})
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa09"), "name" : "小红", "sex" : "女", "score1" : 100, "score2" : 100, "score3" : 100, "score5" : 80, "classID: " : 3 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0d"), "name" : "小王", "sex" : "女", "score1" : 100, "score2" : 100, "score3" : 100, "score5" : 99, "classID: " : 1 }
>
**or： 查询socre1 等于 53 或者score2等于 94 的文档 **
> db.stu_info.find({$or:[{"score1":53},{"score2":94}]})
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0c"), "name" : "小李", "sex" : "女", "score1" : 53, "score2" : 91, "score3" : 34, "score5" : 19, "classID: " : 9 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0e"), "name" : "小周", "sex" : "女", "score1" : 99, "score2" : 94, "score3" : 92, "score5" : 90, "classID: " : 6 }
>
and 和 or 联合查询 ：查询sex 等于 男 ，在此基础上 查询 score1 等于 99 或者 score1 等于 91 的文档
> db.stu_info.find({"sex":"女",$or:[{"score1":99},{"score2":91}]})
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0c"), "name" : "小李", "sex" : "女", "score1" : 53, "score2" : 91, "score3" : 34, "score5" : 19, "classID: " : 9 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0e"), "name" : "小周", "sex" : "女", "score1" : 99, "score2" : 94, "score3" : 92, "score5" : 90, "classID: " : 6 }
>
排序查询： 对score1进行升序和降序排序
1: 升序
-1: 降序
> db.stu_info.find().sort({"score1":1})
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0c"), "name" : "小李", "sex" : "女", "score1" : 53, "score2" : 91, "score3" : 34, "score5" : 19, "classID: " : 9 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0a"), "name" : "小赵", "sex" : "女", "score1" : 80, "score2" : 79, "score3" : 33, "score5" : 55, "classID: " : 3 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0b"), "name" : "小钱", "sex" : "男", "score1" : 89, "score2" : 36, "score3" : 102, "score5" : 65, "classID: " : 5 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa08"), "name" : "小明", "sex" : "男", "score1" : 98, "score2" : 60, "score3" : 79, "score5" : 101, "classID: " : 1 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0e"), "name" : "小周", "sex" : "女", "score1" : 99, "score2" : 94, "score3" : 92, "score5" : 90, "classID: " : 6 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa09"), "name" : "小红", "sex" : "女", "score1" : 100, "score2" : 100, "score3" : 100, "score5" : 80, "classID: " : 3 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0d"), "name" : "小王", "sex" : "女", "score1" : 100, "score2" : 100, "score3" : 100, "score5" : 99, "classID: " : 1 }
>
> db.stu_info.find().sort({"score1":-1})
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa09"), "name" : "小红", "sex" : "女", "score1" : 100, "score2" : 100, "score3" : 100, "score5" : 80, "classID: " : 3 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0d"), "name" : "小王", "sex" : "女", "score1" : 100, "score2" : 100, "score3" : 100, "score5" : 99, "classID: " : 1 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0e"), "name" : "小周", "sex" : "女", "score1" : 99, "score2" : 94, "score3" : 92, "score5" : 90, "classID: " : 6 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa08"), "name" : "小明", "sex" : "男", "score1" : 98, "score2" : 60, "score3" : 79, "score5" : 101, "classID: " : 1 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0b"), "name" : "小钱", "sex" : "男", "score1" : 89, "score2" : 36, "score3" : 102, "score5" : 65, "classID: " : 5 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0a"), "name" : "小赵", "sex" : "女", "score1" : 80, "score2" : 79, "score3" : 33, "score5" : 55, "classID: " : 3 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0c"), "name" : "小李", "sex" : "女", "score1" : 53, "score2" : 91, "score3" : 34, "score5" : 19, "classID: " : 9 }
>
指定返回域: 获取name 和 score1 域的数据
> db.stu_info.find({},{"name":1,"score1":1})
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa08"), "name" : "小明", "score1" : 98 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa09"), "name" : "小红", "score1" : 100 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0a"), "name" : "小赵", "score1" : 80 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0b"), "name" : "小钱", "score1" : 89 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0c"), "name" : "小李", "score1" : 53 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0d"), "name" : "小王", "score1" : 100 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0e"), "name" : "小周", "score1" : 99 }
>
只返回一条：查询socre1小于等于100的数据，仅返回一条
> db.stu_info.findOne({"score1": {$lte: 100}})
{
"_id" : ObjectId("61d6cac2a5a7b57ea8e0aa08"),
"name" : "小明",
"sex" : "男",
"score1" : 98,
"score2" : 60,
"score3" : 79,
"score5" : 101,
"classID: " : 1
}
>
只返回一条并且删除该数据：查询socre1小于等于100的数据，仅返回一条，并且删除
> db.stu_info.findOneAndDelete({"score1":{$lte:100}})
{
"_id" : ObjectId("61d6cac2a5a7b57ea8e0aa08"),
"name" : "小明",
"sex" : "男",
"score1" : 98,
"score2" : 60,
"score3" : 79,
"score5" : 101,
"classID: " : 1
}
> db.stu_info.findOne({"name":"小明"})
null
>
4. 更新操作
4.1 用法
更新一个文档
db.CollectionName.updateOne()
更新多个文档
db.CollectionName.updateOne()
db.CollectionName.updateMany()
4.2 例子
只更新一个文档：将 score1 为 100 的文档 新增一个classID 为 16
> db.stu_info.find({"score1":100})
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa09"), "name" : "小红", "sex" : "女", "score1" : 100, "score2" : 100, "score3" : 100, "score5" : 80, "classID: " : 3 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0d"), "name" : "小王", "sex" : "女", "score1" : 100, "score2" : 100, "score3" : 100, "score5" : 99, "classID: " : 1 }
>
> db.stu_info.updateOne({"score1":100},{$set:{"classID":16}})
{ "acknowledged" : true, "matchedCount" : 1, "modifiedCount" : 1 }
>
> db.stu_info.find({"score1":100})
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa09"), "name" : "小红", "sex" : "女", "score1" : 100, "score2" : 100, "score3" : 100, "score5" : 80, "classID: " : 3, "classID" : 16 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0d"), "name" : "小王", "sex" : "女", "score1" : 100, "score2" : 100, "score3" : 100, "score5" : 99, "classID: " : 1 }
>
更新多个文档
更新所有文档：将 score1 为 100 的文档 设置 新增/设置一个 classID 为 21
> db.stu_info.find({"score1":100})
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa09"), "name" : "小红", "sex" : "女", "score1" : 100, "score2" : 100, "score3" : 100, "score5" : 80, "classID: " : 3, "classID" : 16 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0d"), "name" : "小王", "sex" : "女", "score1" : 100, "score2" : 100, "score3" : 100, "score5" : 99, "classID: " : 1 }
>
> db.stu_info.updateMany({"score1":100},{$set:{"classID":21}})
{ "acknowledged" : true, "matchedCount" : 2, "modifiedCount" : 2 }
>
> db.stu_info.find({"score1":100})
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa09"), "name" : "小红", "sex" : "女", "score1" : 100, "score2" : 100, "score3" : 100, "score5" : 80, "classID: " : 3, "classID" : 21 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0d"), "name" : "小王", "sex" : "女", "score1" : 100, "score2" : 100, "score3" : 100, "score5" : 99, "classID: " : 1, "classID" : 21 }
>
5. 删除操作
5.1 用法
删除一条文档
db.CollectionName.deleteOne()
删除多条文档
db.CollectionName.deleteMany()
5.2 例子
删除一条文档：删除socre1为100的一条文档
> db.stu_info.find({"score1":100})
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa09"), "name" : "小红", "sex" : "女", "score1" : 100, "score2" : 100, "score3" : 100, "score5" : 80, "classID: " : 3, "classID" : 21 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0d"), "name" : "小王", "sex" : "女", "score1" : 100, "score2" : 100, "score3" : 100, "score5" : 99, "classID: " : 1, "classID" : 21 }
>
> db.stu_info.deleteOne({"score1":100})
{ "acknowledged" : true, "deletedCount" : 1 }
>
> db.stu_info.find({"score1":100})
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0d"), "name" : "小王", "sex" : "女", "score1" : 100, "score2" : 100, "score3" : 100, "score5" : 99, "classID: " : 1, "classID" : 21 }
>
删除多条文档: 删除socre1小于90的所有文档
> db.stu_info.find({"score1":{$lt:90}})
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0a"), "name" : "小赵", "sex" : "女", "score1" : 80, "score2" : 79, "score3" : 33, "score5" : 55, "classID: " : 3 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0b"), "name" : "小钱", "sex" : "男", "score1" : 89, "score2" : 36, "score3" : 102, "score5" : 65, "classID: " : 5 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0c"), "name" : "小李", "sex" : "女", "score1" : 53, "score2" : 91, "score3" : 34, "score5" : 19, "classID: " : 9 }
>
> db.stu_info.deleteMany({"score1":{$lt:90}});
{ "acknowledged" : true, "deletedCount" : 3 }
>
> db.stu_info.find({"score1":{$lt:90}})
>
6. 索引操作
6.1 用法
查询集合所有
db.CollectionName.getIndexes()
创建索引
db.CollectionName.createIndex()
删除集合除_id以外的所有索引
db.CollectionName.dropIndexes()
删除索引
db.CollectionName.dropIndex()
6.2 例子
查询集合所有
> db.stu_info.getIndexes()
[
{
"v" : 2,
"key" : {
"_id" : 1
},
"name" : "_id_",
"ns" : "LearnDB.stu_info"
}
]
>
创建索引
语法
db.collection.createIndex(
{
"a": 1
},
{
unique: true,
sparse: true,
expireAfterSeconds: 3600
}
)
可选参数
background: bool类型 为true则在后台构建索引，默认为false
unique: bool类型 为true则创建唯一索引，默认为false
name: string类型 索引名称, 如果未指定，mongodb将通过索引字段和排序来生成索引名称
sparse: bool类型 为true则对文档不存在字段数据不启用索引，默认为false
expireAfterSeconds: 整形 指定一个值(以秒为单位)作为TTL，设置生存时间
例子1： 给集合stu_info sex name 增加唯一索引
> db.stu_info.getIndexes()
[
{
"v" : 2,
"key" : {
"_id" : 1
},
"name" : "_id_",
"ns" : "LearnDB.stu_info"
}
]
>
> db.stu_info.createIndex({"name":1} , {"background":true,"unique":true , "name":"stu_info_name"})
{
"createdCollectionAutomatically" : false,
"numIndexesBefore" : 1,
"numIndexesAfter" : 2,
"ok" : 1
}
>
> db.stu_info.getIndexes()
[
{
"v" : 2,
"key" : {
"_id" : 1
},
"name" : "_id_",
"ns" : "LearnDB.stu_info"
},
{
"v" : 2,
"unique" : true,
"key" : {
"name" : 1
},
"name" : "stu_info_name",
"ns" : "LearnDB.stu_info",
"background" : true
}
]
>
尝试新增相同name的文档
> db.stu_info.find()
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0d"), "name" : "小王", "sex" : "女", "score1" : 100, "score2" : 100, "score3" : 100, "score5" : 99, "classID: " : 1, "classID" : 21 }
{ "_id" : ObjectId("61d6cac2a5a7b57ea8e0aa0e"), "name" : "小周", "sex" : "女", "score1" : 99, "score2" : 94, "score3" : 92, "score5" : 90, "classID: " : 6 }
>
> db.stu_info.insertMany([ {"name": "小王" , "sex": "女" , "score1": 100 , "score2": 100, "score3": 100 , "score5": 99 , "classID: " : 1} ])
2022-01-08T10:56:46.475+0800 E QUERY [js] BulkWriteError: write error at item 0 in bulk operation :
BulkWriteError({
"writeErrors" : [
{
"index" : 0,
"code" : 11000,
"errmsg" : "E11000 duplicate key error collection: LearnDB.stu_info index: stu_info_name dup key: { : \"小王\" }",
"op" : {
"_id" : ObjectId("61d8fd6e3a0069c72ccea003"),
"name" : "小王",
"sex" : "女",
"score1" : 100,
"score2" : 100,
"score3" : 100,
"score5" : 99,
"classID: " : 1
}
}
],
"writeConcernErrors" : [ ],
"nInserted" : 0,
"nUpserted" : 0,
"nMatched" : 0,
"nModified" : 0,
"nRemoved" : 0,
"upserted" : [ ]
})
BulkWriteError@src/mongo/shell/bulk_api.js:369:48
BulkWriteResult/this.toError@src/mongo/shell/bulk_api.js:333:24
Bulk/this.execute@src/mongo/shell/bulk_api.js:1173:1
DBCollection.prototype.insertMany@src/mongo/shell/crud_api.js:314:5
@(shell):1:1
>
删除索引：删除stu_info name 索引
> db.stu_info.getIndexes()
[
{
"v" : 2,
"key" : {
"_id" : 1
},
"name" : "_id_",
"ns" : "LearnDB.stu_info"
},
{
"v" : 2,
"unique" : true,
"key" : {
"name" : 1
},
"name" : "stu_info_name",
"ns" : "LearnDB.stu_info",
"background" : true
}
]
>
> db.stu_info.dropIndex("stu_info_name")
{ "nIndexesWas" : 2, "ok" : 1 }
>
> db.stu_info.getIndexes()
[
{
"v" : 2,
"key" : {
"_id" : 1
},
"name" : "_id_",
"ns" : "LearnDB.stu_info"
}
]
>
完