mongodb系列(2)-基本的CURD的使用

CRUD操作是create（创建）、read（读取）、update（更新）和delete（删除）文章源自玩技e族-https://www.playezu.com/744514.html

MongoDB不支持常规的sql的命令，但是自身有丰富的查询语言文章源自玩技e族-https://www.playezu.com/744514.html

MongoDB在插入一条数据后，会自动增加一个_id自动，作为主键，如果插入的文档省略了id字段，则会自动生产一个Object_id字段文章源自玩技e族-https://www.playezu.com/744514.html

MongoDB默认有4个数据库：文章源自玩技e族-https://www.playezu.com/744514.html

test：登陆时默认存在的库，不切换其他库时默认存在的库文章源自玩技e族-https://www.playezu.com/744514.html

admin：系统预留库，MongoDB系统管理库文章源自玩技e族-https://www.playezu.com/744514.html

local：本地预留库，存储关键日志文章源自玩技e族-https://www.playezu.com/744514.html

config：MongoDB配置信息库文章源自玩技e族-https://www.playezu.com/744514.html

mongo默认登陆的时候是在test库下文章源自玩技e族-https://www.playezu.com/744514.html

mongo不需要提前创建库和表，直接use切换就是创建库，直接插入数据就会创建表文章源自玩技e族-https://www.playezu.com/744514.html

使用use切换到的库，如果没有任何数据，实际上并不会真正创建，是个虚的库，所以show dbs并不会显现，只有在插入数据后，数据库才会真正创建

- (>) 大于 - $gt
- (<) 小于 - $lt
- (>=) 大于等于 - $gte
- (<= ) 小于等于 - $lte

二. 常用命令

三. 常用命令探索 1. 展示数据库

docker exec -it 1c87ff69af43a8253b7ccff671b9fc66a52aa0bdc5fbecbf5b9efb7145550824 /bin/sh
mongo
#查询当前有多少个数据库
> show databases
#显示当前所在的数据库
> db
test
#显示当前所在的数据库表信息
> show tables
users

2. 插入数据

db.users.insert({"_id":"tomxiang","name":"向少","age":1000})
db.users.insert({"_id":"sally","name":"hebinbin","age":1000,"fruit":"apple"})
db.users.insert({"name":"xiaozi","ad":"石家庄市","job":"guanggao"})

查看结果

db.users.find()

{ "_id" : "easydoc", "name" : "易文档", "age" : 18 }

{ "_id" : "tomxiang", "name" : "向少", "age" : 1000 }

{ "_id" : "sally", "name" : "hebinbin", "age" : 1000, "fruit" : "apple" }

{ "_id" : ObjectId("63520158ebc6c7e46c33e464"), "name" : "xiaozi", "ad" : "石家庄市", "job" : "guanggao" }

image.png 2. 插入多条数据

语法格式：db.表名.insertMany({“字段1”:“值1”,“字段2”:“值2”},{“字段1”:“值1”,“字段2”:“值2”})

使用insertMany插入的数据，会自动生产ObjectId

db.book_date.insertMany([
    { "name":"Nginx", "price":25, "num":100, "status":"N" },
    { "name":"ansible", "price":50, "num":200 , "status":"A" },
    { "name":"tomcat", "price":100, "num":150, "status":"T" },
    { "name":"redis", "price":75, "num":320  , "status":"R" },
    { "name":"docker", "price":45, "num":270, "status":"D" }
]);

image.png 3. 插入嵌套数据

> db.nest_date.insertMany( [
... ...     { "item": "journal", "qty": 25, "size": { "h": 14, "w": 21, "uom": "cm" }, "status": "A" },
... ...     { "item": "notebook", "qty": 50, "size": { "h": 8.5, "w": 11, "uom": "in" }, "status": "A" },
... ...     { "item": "paper", "qty": 100, "size": { "h": 8.5, "w": 11, "uom": "in" }, "status": "D" },
... ...     { "item": "planner", "qty": 75, "size": { "h": 22.85, "w": 30, "uom": "cm" }, "status": "D" },
... ...     { "item": "postcard", "qty": 45, "size": { "h": 10, "w": 15.25, "uom": "cm" }, "status": "A" }
... ... ]);
{
	"ackNowledged" : true,
	"insertedIds" : [
		ObjectId("63524279b7e4788da144a282"),
		ObjectId("63524279b7e4788da144a283"),
		ObjectId("63524279b7e4788da144a284"),
		ObjectId("63524279b7e4788da144a285"),
		ObjectId("63524279b7e4788da144a286")
	]
}
> db.nest_date.find()
{ "_id" : ObjectId("63524279b7e4788da144a282"), "item" : "journal", "qty" : 25, "size" : { "h" : 14, "w" : 21, "uom" : "cm" }, "status" : "A" }
{ "_id" : ObjectId("63524279b7e4788da144a283"), "item" : "notebook", "qty" : 50, "size" : { "h" : 8.5, "w" : 11, "uom" : "in" }, "status" : "A" }
{ "_id" : ObjectId("63524279b7e4788da144a284"), "item" : "paper", "qty" : 100, "size" : { "h" : 8.5, "w" : 11, "uom" : "in" }, "status" : "D" }
{ "_id" : ObjectId("63524279b7e4788da144a285"), "item" : "planner", "qty" : 75, "size" : { "h" : 22.85, "w" : 30, "uom" : "cm" }, "status" : "D" }
{ "_id" : ObjectId("63524279b7e4788da144a286"), "item" : "postcard", "qty" : 45, "size" : { "h" : 10, "w" : 15.25, "uom" : "cm" }, "status" : "A" }

3. 查询数据 1. 基本查询

> db.book_date.find({"status":"N"})
{ "_id" : ObjectId("63524ec3b7e4788da144a287"), "name" : "Nginx", "price" : 199, "num" : 530, "status" : "N", "lastModified" : ISODate("2022-10-21T08:18:11.206Z") }

2. 关键字:
or

查询book_date表status等于T或者price小于50的数据

db.book_date.find({$or: {"status": "T"},{"price": {$lt: 50}}}) { "_id" : ObjectId("635241f3b7e4788da144a281"), "name" : "docker", "price" : 45, "num" : 270, "status" : "D" }

4. 删除数据

语法格式：

删除一个：db.表名.deleteOne({“条件1”:“值1”})

删除多个：db.表名.deleteMany({“条件1”:“值1”})

1. 删除一条数据

> db.book_date.deleteOne({"name":"Nginx"})
{ "ackNowledged" : true, "deletedCount" : 1 }

2. 删除多条数据

> db.book_date.deleteMany({"num":{$lt:200}})
{ "ackNowledged" : true, "deletedCount" : 2 }

5. 修改数据

mongodb更新一条数据后，会在最后增加一个新的字段，记录更新的时间

语法格式：

更新一条数据：db.表名.updateOne({“匹配条件1”:"值"1},{set:{"更新的字段1":"新值1","更新字段2":"新值2"},currentDate:{“lastModified”:true}})

更新多条数据：db.表名.updateMany({“匹配条件1”:"值"1},{set:{"更新的字段1":"新值1","更新字段2":"新值2"},currentDate:{“lastModified”:true}})

使用update更新：db.表名.update({“匹配条件1”:"值"1},{set:{"更新的字段1":"新值1","更新字段2":"新值2"},currentDate:{“lastModified”:true}})

• updateMany = update + {multi: true}
• updateOne = update 或 update + {multi: false} -因为 update 本身的意义不够清楚，所以3.0以后才出现了 updateMany 和 updateOne 两个替代方法。这个方法没多少要说的，唯一要注意的就是，如果用 update 方法的话，不要忘记操作符（ $set , $inc 等等），不然…… updateMany 和 updateOne 则没有这个问题，缺了操作符会直接报错。

1. 更新一条数据

> db.book_date.updateOne({"name":"Nginx"},{$set:{"price":500,"num":230},$currentDate:{"lastModified":true}})
{ "ackNowledged" : true, "matchedCount" : 1, "modifiedCount" : 1 }
> db.book_date.find({"name":"Nginx"})
{ "_id" : ObjectId("63524ec3b7e4788da144a287"), "name" : "Nginx", "price" : 500, "num" : 230, "status" : "N", "lastModified" : ISODate("2022-10-21T08:00:39.111Z") }

解释：

$currentDate: {

    "lastModified": true            //增加一个字段，每次更新都记录时间

}

2. 更新多条数据

num小于250的数据，将price修改为99，num修改为530

> db.book_date.updateMany({"num":{$lt:250}},{$set:{"price":99,"num":530},$currentDate:{"lastModified":true}})
{ "ackNowledged" : true, "matchedCount" : 2, "modifiedCount" : 2 }
> db.book_date.find()
{ "_id" : ObjectId("635241f3b7e4788da144a27e"), "name" : "ansible", "price" : 99, "num" : 530, "status" : "A", "lastModified" : ISODate("2022-10-21T08:13:08.799Z") }
{ "_id" : ObjectId("635241f3b7e4788da144a280"), "name" : "redis", "price" : 75, "num" : 320, "status" : "R" }
{ "_id" : ObjectId("635241f3b7e4788da144a281"), "name" : "docker", "price" : 45, "num" : 270, "status" : "D" }
{ "_id" : ObjectId("63524ec3b7e4788da144a287"), "name" : "Nginx", "price" : 99, "num" : 530, "status" : "N", "lastModified" : ISODate("2022-10-21T08:13:08.799Z") }

参考文章

1. MongoDB数据库增删改查基本使用
2. MongoDB中文手册|官方文档中文版

原文地址：https://cloud.tencent.com/developer/article/2137685