MongoDB学习总结（1）----基本概念和基本操作

谁借莪１个温暖的怀抱￠ 2022-11-02 11:39 193阅读 0赞

#### 基本概念 ####

数据库分为TRDB和NoSQL  
TRDB包含Oracle（第一款）、MySQL等  
NoSQL包含MongoDB、Redis等

> NoSQL：是一种非关系型DMS，不需要固定的架构，可以避免joins链接，并且易于扩展。  
> ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzI4Njg2OTEx_size_16_color_FFFFFF_t_70]  
> MongoDB数据库构成：  
> 数据库<集合<文档<字段  
> \_id：唯一标识，主键  
> 游标：指向查询结果集的指针  
> 数据库：集合容器  
> 集合：文档的分组，存在于单个数据库中  
> 文档：集合中的记录，包含字段名称和值  
> 字段：文档中的 （名称/值） 对

#### 基本操作 ####

`MongoDB创建数据库:use DBname`

rs:PRIMARY> use Employee
    switched to db Employee

`创建集合/表:insert()`

rs:PRIMARY> db.Employee.insert(
    ... { 
    ... "编号":1,
    ... "EmployeeName":"Smith"
    ... }
    ... )
    WriteResult({  "nInserted" : 1 })
    rs:PRIMARY>

`insert()还可以插入数组`

rs:PRIMARY> var myEmployee = [ { "编号":2, "EmployeeName":"Smith2"},{ "编号":3,"EmployeeName":"Smith3"}]
    rs:PRIMARY> db.Employee.insert(myEmployee)
    BulkWriteResult({ 
    	"writeErrors" : [ ],
    	"writeConcernErrors" : [ ],
    	"nInserted" : 2,
    	"nUpserted" : 0,
    	"nMatched" : 0,
    	"nModified" : 0,
    	"nRemoved" : 0,
    	"upserted" : [ ]
    })
    rs:PRIMARY>

`查询文档`

rs:PRIMARY> db.Employee.find()
    {  "_id" : ObjectId("6033295c785939f88516b7f4"), "Employeeid" : 1, "EmployeeName" : "Smith" }
    {  "_id" : ObjectId("6033295c785939f88516b7f5"), "Employeeid" : 2, "EmployeeName" : "Mohan" }
    {  "_id" : ObjectId("6033295c785939f88516b7f6"), "Employeeid" : 3, "EmployeeName" : "Joe" }
    {  "_id" : 10, "EmployeeName" : "Smith" }
    rs:PRIMARY>

`条件查询`

rs:PRIMARY> db.Employee.find({ EmployeeName:"Smith"}).forEach(printjson)
    { 
    	"_id" : ObjectId("6033295c785939f88516b7f4"),
    	"Employeeid" : 1,
    	"EmployeeName" : "Smith"
    }
    {  "_id" : 10, "EmployeeName" : "Smith" }
    rs:PRIMARY> db.Employee.find({ Employeeid:{ $gt:2}}).forEach(printjson)
    { 
    	"_id" : ObjectId("6033295c785939f88516b7f6"),
    	"Employeeid" : 3,
    	"EmployeeName" : "Joe"
    }
    rs:PRIMARY>

`查询修饰符 limit`

rs:PRIMARY> db.Employee.find().limit(2).forEach(printjson)
    { 
    	"_id" : ObjectId("6033295c785939f88516b7f4"),
    	"Employeeid" : 1,
    	"EmployeeName" : "Smith"
    }
    { 
    	"_id" : ObjectId("6033295c785939f88516b7f5"),
    	"Employeeid" : 2,
    	"EmployeeName" : "Mohan"
    }
    rs:PRIMARY>

`排序查询：1为升序，-1为降序`

rs:PRIMARY> db.Employee.find().sort({ Employeeid:-1}).forEach(printjson)
    { 
    	"_id" : ObjectId("6033295c785939f88516b7f6"),
    	"Employeeid" : 3,
    	"EmployeeName" : "Joe"
    }
    { 
    	"_id" : ObjectId("6033295c785939f88516b7f5"),
    	"Employeeid" : 2,
    	"EmployeeName" : "Mohan"
    }
    { 
    	"_id" : ObjectId("6033295c785939f88516b7f4"),
    	"Employeeid" : 1,
    	"EmployeeName" : "Smith"
    }
    {  "_id" : 10, "EmployeeName" : "Smith" }
    rs:PRIMARY>

`查询集合中文档数量count()`

rs:PRIMARY> db.Employee.count()
    4
    rs:PRIMARY>

`执行文档修改操作`  
`删除 remove()`

rs:PRIMARY> db.Employee.remove({ Employeeid:2})
    WriteResult({  "nRemoved" : 1 })
    rs:PRIMARY> db.Employee.find()
    {  "_id" : ObjectId("6033295c785939f88516b7f4"), "Employeeid" : 1, "EmployeeName" : "Smith" }
    {  "_id" : ObjectId("6033295c785939f88516b7f6"), "Employeeid" : 3, "EmployeeName" : "Joe" }
    {  "_id" : 10, "EmployeeName" : "Smith" }
    rs:PRIMARY>

`更新单个/多个值 update()`

rs:PRIMARY> db.Employee.update(
    ... { "Employeeid":1},{ $set:{ "EmployeeName":"NewSmith"}})
    WriteResult({  "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
    rs:PRIMARY> db.Employee.find()
    {  "_id" : ObjectId("6033295c785939f88516b7f4"), "Employeeid" : 1, "EmployeeName" : "NewSmith" }
    {  "_id" : ObjectId("6033295c785939f88516b7f6"), "Employeeid" : 3, "EmployeeName" : "Joe" }
    {  "_id" : 10, "EmployeeName" : "Smith" }
    rs:PRIMARY>

`正则匹配 $regex`  
`忽略大小写 $option:"i"`

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