# miniMongoDB

**Repository Path**: LiuDan1119/miniMongoDB

## Basic Information

- **Project Name**: miniMongoDB
- **Description**: mini版mongoDB数据库实现
- **Primary Language**: Java
- **License**: Not specified
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2017-04-05
- **Last Updated**: 2020-12-19

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

## MongoDb



##使用方式请参考项目中TestCase




**启动链接命令：**

  * 启动命令：mongod --dbpath data/db
  * 链接命令：mongo 127.0.0.1:27017/admin
  
**文档命令**
 	
 * use dbname --新建数据库
 * db.drop() --删除
 * show dbs --显示
 * show collections --显示数据库的集合 
 * 批量插入数据：
 
```
   //批量插入
   for(var i=0;i<10;i++)
   { 
   		db.persions.insert({name:i}) 
   }
   //查询
   db.persions.find()
```
   
* insert 和 save的区别（insert是插入，如果有重复的则报错，save如果有重复的，则执行更新操作）
   
```
   { "_id" : "001", "name" : 100 }
   db.persions.insert({"_id":"001",name:111})
   执行结果：
   WriteResult({
	"nInserted" : 0,
	"writeError" : {
		"code" : 11000,
		"errmsg" : "E11000 duplicate key error collection: foobar.persions index: _id_ dup key: { : \"001\" }"
	}})
    db.persions.save({"_id":"001",name:111})
    执行结果：
    WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
    { "_id" : "001", "name" : 111 }

```

 **修改器**

   * $set 修改器用来指定一个键值，如果存在，则修改，不存在，则创建。
	
```
	//修改前：{ "_id" : "001", "name" : 111 }
	db.persions.update({"name":"111"},{"$set":{"age":20}})
	//修改后：{ "_id" : "001", "name" : 111, "age" : 20 }
	
	//批量修改
	 db.persons.update({country:"China"},{$set:{sex:"M"}},false,true)
```
	
   * $inc 修改器用来指定一个键值，如果存在则修改，不存在则创建。（可用于主键自增）
   
```
   //修改前数据{ "_id" : "001", "name" : 111, "age" : 20 }
   db.persions.update({name:111},{$inc:{age:1}})
   //修改后数据
   { "_id" : "001", "name" : 111, "age" : 21 }
```
   
  * $unset 修改器用来删除指定键
  
```
	  //执行前有数据
	  { "_id" : ObjectId("58ce993b5bc83f2fd0964f25"), "name" : "liu" }
	   db.persions.update({name:"liu"},{$unset:{name:1}})
	   //执行后数据消失
```

* $push 数组修改器数组修改器，顾名思义它只可以用于操作数组，只能用在值为数组的键上。修改器如果指定的值已经存在，"push"会想已有的数组末尾加入一个元素，要是没有就会创建一个新的数组。

```
//执行插入一条数据
db.persions.insert({"_id":002,name:"002",books:[]})
	//调用push
	db.persions.update({"_id:2},{$push:{books:"js"}}})
	db.persions.update({"_id":2},{$push:{books:"jeasyui"}})
	//查询
	{ "_id" : 2, "name" : "002", "books" : [ "js", "jeasyui" ] }
```



**查询**
   * Find
1. 查询指定的返回字段
语法：db.[documentName].find({条件},{键指定})

````
//0代表不查询，1代表查询 第一个{}代表查询所有
 db.persons.find({},{_id:0,name:1,email:1})
 //结果
 { "name" : "jim", "email" : "75431457@qq.com" }
 { "name" : "tom", "email" : "214557457@qq.com" }
 { "name" : "lili", "email" : "344521457@qq.com" }
````

2. 查询条件 $lt <  $lte <=  $gt > $gte >= $ne !=   例如：{age:{$gte:22,$lte:27}}
```
//1. 条件查询
 //查询年龄 >=21 and <=23
  db.persons.find({age:{$gte:21,$lte:23}},{_id:0,name:1,age:1,email:1})
 { "name" : "lixiaoli", "age" : 21, "email" : "lixiaoli@uspcat.com" }
 { "name" : "zhangsuying", "age" : 22, "email" : "zhangsuying@uspcat.com" }
 //查询不是韩国学生的数学成绩
 db.persons.find({country:{$ne:"Korea"}},{_id:0,name:1,age:1,m:1,country:1})
 { "name" : "jim", "age" : 25, "m" : 96, "country" : "USA" }
 { "name" : "tom", "age" : 25, "m" : 66, "country" : "USA" }
 { "name" : "lili", "age" : 26, "m" : 63, "country" : "USA" }
 { "name" : "zhangsan", "age" : 27, "m" : 86, "country" : "China" }
 { "name" : "lisi", "age" : 26, "m" : 96, "country" : "China" }
 { "name" : "wangwu", "age" : 27, "m" : 65, "country" : "China" }
 { "name" : "zhaoliu", "age" : 27, "m" : 96, "country" : "China" }
 
 // 2. 包含或不包含
 //查询出包含美国跟中国的学生
 db.persons.find({country:{$in:["USA","China"]}},{_id:0,name:1,age:1,m:1,country:1})
 { "name" : "jim", "age" : 25, "m" : 96, "country" : "USA" }
 { "name" : "tom", "age" : 25, "m" : 66, "country" : "USA" }
 { "name" : "lili", "age" : 26, "m" : 63, "country" : "USA" }
 { "name" : "zhangsan", "age" : 27, "m" : 86, "country" : "China" }
 { "name" : "lisi", "age" : 26, "m" : 96, "country" : "China" }
 { "name" : "wangwu", "age" : 27, "m" : 65, "country" : "China" }
 { "name" : "zhaoliu", "age" : 27, "m" : 96, "country" : "China" }
 
 //查询不包含中国跟美国的学生
 db.persons.find({country:{$nin:["USA","China"]}},{_id:0,name:1,age:1,m:1,country:1})
 { "name" : "piaoyingjun", "age" : 26, "m" : 54, "country" : "Korea" }
 { "name" : "lizhenxian", "age" : 27, "m" : 56, "country" : "Korea" }
 { "name" : "lixiaoli", "age" : 21, "m" : 86, "country" : "Korea" }
 { "name" : "zhangsuying", "age" : 22, "m" : 63, "country" : "Korea" }
 
 // 查询语文大于85 英语小于97的学生
 db.persons.find({$or:[{c:{$gt:85},e:{$lt:97}}]},{_id:0,name:1,c:1,e:1})
 { "name" : "jim", "c" : 89, "e" : 87 }
 { "name" : "zhangsan", "c" : 89, "e" : 67 }
 
 //查询sex为null的学生
 db.persons.find({sex:{$in:[null]}},{_id:0,name:1,sex:1})
 { "name" : "jim" }
 { "name" : "tom" }
 { "name" : "lili" }
 { "name" : "piaoyingjun" }
 { "name" : "lizhenxian" }
 { "name" : "lixiaoli" }
 { "name" : "zhangsuying" }
 //正则查询 ／li/i
 db.persons.find({name:/li/i},{_id:0,name:1,email:1})
 { "name" : "lili", "email" : "344521457@qq.com" }
 { "name" : "lisi", "email" : "274521457@qq.com" }
 { "name" : "zhaoliu", "email" : "214521457@qq.com" }
 { "name" : "lizhenxian", "email" : "lizhenxian@uspcat.com" }
 { "name" : "lixiaoli", "email" : "lixiaoli@uspcat.com" }
 
 //$not可以用到任何地方进行取反
  db.persons.find({name:{$not:/li/i}},{_id:0,name:1,email:1})
 { "name" : "jim", "email" : "75431457@qq.com" }
 { "name" : "tom", "email" : "214557457@qq.com" }
 { "name" : "zhangsan", "email" : "2145567457@qq.com" }
 { "name" : "wangwu", "email" : "65621457@qq.com" }
 { "name" : "piaoyingjun", "email" : "piaoyingjun@uspcat.com" }
 { "name" : "zhangsuying", "email" : "zhangsuying@uspcat.com" }
 
 //数组查询$all
  db.persons.find({books:{$all:["JS"]}},{_id:0,name:1,email:1})
 { "name" : "jim", "email" : "75431457@qq.com" }
 { "name" : "lili", "email" : "344521457@qq.com" }
 { "name" : "zhangsan", "email" : "2145567457@qq.com" }
 { "name" : "lisi", "email" : "274521457@qq.com" }
 { "name" : "wangwu", "email" : "65621457@qq.com" }
 { "name" : "zhaoliu", "email" : "214521457@qq.com" }
 { "name" : "piaoyingjun", "email" : "piaoyingjun@uspcat.com" }
 { "name" : "lizhenxian", "email" : "lizhenxian@uspcat.com" }
 { "name" : "lixiaoli", "email" : "lixiaoli@uspcat.com" }
 { "name" : "zhangsuying", "email" : "zhangsuying@uspcat.com" }
 
 //$elemMatch数组对象查询
  db.persons.find({school:{$elemMatch:{school:"K",score:"A"}}},{_id:0,name:1,email:1})
 { "name" : "jim", "email" : "75431457@qq.com" }
 
 
 $where万能的查询语句
 db.persons.find({"$where":function(){
 	//得到查询结果的每一条文档
 	var books = this.books;
 	//得到文档中的school对象
 	var school = this.school;
 	//如果年纪>=22
 	if(this.age > 22){
 		var php = null;
 		//遍历书籍
 		for ( var i = 0; i < books.length; i++) {
 			if(books[i] == "C++"){
 				php = books[i];
 				//如果学校是真
 				if(school){
 					for (var j = 0; j < school.length; j++) {
 						//判断是不是在K上学
 						if(school[j].school == "K"){
 							//返回是真
 							return true;
 						}
 					}
 					break;
 				}
 			}
 		}	
 	}
 }}) 
 
 { "_id" : ObjectId("58de7dc6a724a9151e4b9d82"), "name" : "jim", "age" : 25, "email" : "75431457@qq.com", "c" : 89, "m" : 96, "e" : 87, "country" : "USA", "books" : [ "JS", "C++", "EXTJS", "MONGODB" ], "school" : [ { "school" : "K", "score" : "A" }, { "school" : "L", "score" : "B" }, { "school" : "J", "score" : "A+" } ] }
 
 //$limit 分页查询
 > db.persons.find({},{_id:0,name:1,email:1}).limit(5)
 { "name" : "jim", "email" : "75431457@qq.com" }
 { "name" : "tom", "email" : "214557457@qq.com" }
 { "name" : "lili", "email" : "344521457@qq.com" }
 { "name" : "zhangsan", "email" : "2145567457@qq.com" }
 { "name" : "lisi", "email" : "274521457@qq.com" }
 
 //$skip()跳跃查询，（从第几条开始查询）
 db.persons.find({},{_id:0,name:1,email:1}).limit(5).skip(5)
 { "name" : "wangwu", "email" : "65621457@qq.com" }
 { "name" : "zhaoliu", "email" : "214521457@qq.com" }
 { "name" : "piaoyingjun", "email" : "piaoyingjun@uspcat.com" }
 { "name" : "lizhenxian", "email" : "lizhenxian@uspcat.com" }
 { "name" : "lixiaoli", "email" : "lixiaoli@uspcat.com" }
 
 //排序.sort(age:1) 1正序，-1倒序
  db.persons.find({},{_id:0,name:1,age:1}).limit(5).sort({age:1})
 { "name" : "lixiaoli", "age" : 21 }
 { "name" : "zhangsuying", "age" : 22 }
 { "name" : "jim", "age" : 25 }
 { "name" : "tom", "age" : 25 }
 { "name" : "lili", "age" : 26 }
 
```

**Mongodb 索引**

```$xslt
//插入20万条数据
 for(var i=0;i<200000;i++){
    db.books.insert({number:i,name:i+"book"})
 }
 
var startDate = new Date()
db.books.find({number:56789})
var endDate = new Date()
endDate-startDate

//执行耗时168毫秒
 var startDate = new Date()
> db.books.find({number:56789})
var endDate = new Date()
{ "_id" : ObjectId("58df5bd934f75ed79cc5e990"), "number" : 56789, "name" : "56789book" }
> var endDate = new Date()
> endDate-startDate
168


//为books的number字段创建索引
db.books.ensureIndex({number:1})
//创建索引并且指定索引名称
db.books.ensureIndex({number:1},{name:"bookname"})
//建立完索引只用了2毫秒
var start = new Date()
db.books.find({number:65871})
var end = new Date()
end - start
2


//详细查看本次查询使用的索引以及查询数据状态信息
 db.books.find({name:"0book"}).explain()
{
        "queryPlanner" : {
                "plannerVersion" : 1,
                "namespace" : "foobar.books",
                "indexFilterSet" : false,
                "parsedQuery" : {
                        "name" : {
                                "$eq" : "0book"
                        }
                },
                "winningPlan" : {
                        "stage" : "FETCH",
                        "inputStage" : {
                                "stage" : "IXSCAN",
                                "keyPattern" : {
                                        "name" : 1
                                },
                                "indexName" : "name_1",
                                "isMultiKey" : false,
                                "multiKeyPaths" : {
                                        "name" : [ ]
                                },
                                "isUnique" : false,
                                "isSparse" : false,
                                "isPartial" : false,
                                "indexVersion" : 1,
                                "direction" : "forward",
                                "indexBounds" : {
                                        "name" : [
                                                "[\"0book\", \"0book\"]"
                                        ]
                                }
                        }
                },
                "rejectedPlans" : [ ]
        },
        "serverInfo" : {
                "host" : "bogon",
                "port" : 27017,
                "version" : "3.4.2",
                "gitVersion" : "3f76e40c105fc223b3e5aac3e20dcd026b83b38b"
        },
        "ok" : 1
}

//创建2d集合
> db.map.find()
{ "_id" : ObjectId("58df75fb310cefc5479014c7"), "gis" : { "x" : 185, "y" : 150 } }
{ "_id" : ObjectId("58df75fb310cefc5479014c8"), "gis" : { "x" : 70, "y" : 180 } }
{ "_id" : ObjectId("58df75fb310cefc5479014c9"), "gis" : { "x" : 75, "y" : 180 } }
{ "_id" : ObjectId("58df75fb310cefc5479014ca"), "gis" : { "x" : 185, "y" : 185 } }
{ "_id" : ObjectId("58df75fb310cefc5479014cb"), "gis" : { "x" : 65, "y" : 185 } }
{ "_id" : ObjectId("58df75fb310cefc5479014cc"), "gis" : { "x" : 50, "y" : 50 } }
{ "_id" : ObjectId("58df75fb310cefc5479014cd"), "gis" : { "x" : 50, "y" : 50 } }
{ "_id" : ObjectId("58df75fb310cefc5479014ce"), "gis" : { "x" : 60, "y" : 55 } }
{ "_id" : ObjectId("58df75fb310cefc5479014cf"), "gis" : { "x" : 65, "y" : 80 } }
{ "_id" : ObjectId("58df75fb310cefc5479014d0"), "gis" : { "x" : 55, "y" : 80 } }
{ "_id" : ObjectId("58df75fb310cefc5479014d1"), "gis" : { "x" : 0, "y" : 0 } }
{ "_id" : ObjectId("58df75fb310cefc5479014d2"), "gis" : { "x" : 0, "y" : 200 } }
{ "_id" : ObjectId("58df75fb310cefc5479014d3"), "gis" : { "x" : 200, "y" : 0 } }
{ "_id" : ObjectId("58df75fb310cefc5479014d4"), "gis" : { "x" : 200, "y" : 200 } }
> db.map.ensureIndex({"gis":"2d"},{min:-1,max:200})
{
        "createdCollectionAutomatically" : false,
        "numIndexesBefore" : 1,
        "numIndexesAfter" : 2,
        "ok" : 1
}

//2D数组查询，查询70，到80附近到3个点
 db.map.find({"gis":{$near:[70,80]}},{_id:0}).limit(3)
{ "gis" : { "x" : 65, "y" : 80 } }
{ "gis" : { "x" : 55, "y" : 80 } }
{ "gis" : { "x" : 60, "y" : 55 } }

```


**常用函数**
```$xslt
//查询条数count() 
 db.persons.find({country:"USA"}).count()
3
//数据去重distinct
db.runCommand({distinct:"persons",key:"country"})
{ "values" : [ "USA", "China", "Korea" ], "ok" : 1 }


//查询mongodb所有命令  --rest
db.listCommands() 
启动命令：mongod --dbpath /Users/liudan/Documents/soft/mogon/data/db --rest

//这样才能访问默认端口+1000
http://localhost:28017/_commands


//查询系统信息
db.runCommand({buildinfo:1})


```

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