MongoDB数据库基础

MongoDB简介

MongoDB是一种文档型的非关系型数据库（NoSQL），举例如下：

{“foo”:3,"greeting":"Hello,world!"}

并且区分大小写，key值唯一，不可重复，文档可以嵌套，键值对是有序的

集合

1、集合就是一组文档

2、文档类似于关系库里的行

3、集合类似于关系库里的表

4、集合里的文档无需固定的结构（与关系型数据库的区别）

集合的命名

1、不能是空字符串

2、不能包含字符（空字符）

3、不能使用system.的前缀

4、建议不包含保留字“$”

5、用.分割不同命名空间的子集合（如：blog.users）

数据库

1、多个文档组成集合，多个集合组成数据库

2、一个实例可以承载多个数据库

3、每个数据库都有独立的权限

4、保留的数据库名称（admin,local,config）

命令行操作MongoDB

参考菜鸟教程

在MongoDBServer3.4in进入命令行窗口，然后敲mongo即进入MongoDB服务，显示所有数据库

> show dbs;

使用某一数据库（如果不存在的话则会自动新建）

> use 数据库名称;

插入数据

写数据

> stu = {
        name:'Jhon',
        age:21,
        "sex":"male"
}

插入数据

> db.数据库名称.insert(stu)

查询数据

> db.数据库名称.find()

 

更新数据

> stu_obj = db.students.findOne()
{
        "_id" : ObjectId("5a9a01c5b1489e70f3a89a0c"),
        "name" : "Jhon",
        "age" : 21,
        "sex" : "male"
}
> stu_obj.name = "Jackchen"
Jackchen

> db.students.update({name:"Jhon"},stu_obj)
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })

> db.students.findOne()
{
        "_id" : ObjectId("5a9a01c5b1489e70f3a89a0c"),
        "name" : "Jackchen",
        "age" : 21,
        "sex" : "male"
}

更新数据时，update里第二个参数会完全代替前一个参数，所以如果第二个参数只有{name:"**"}，会把原来的数据删除

如果要更新多个数据，则可以使用updateMany

总结：这种方式更新数据相当麻烦，可以用修改器

删除数据

原来是三条数据：

> db.students.find()
{ "_id" : ObjectId("5a9a01c5b1489e70f3a89a0c"), "name" : "Jhon", "age" : 21, "sex" : "male" }
{ "_id" : ObjectId("5a9a04d9b1489e70f3a89a0d"), "name" : "oldhu" }
{ "_id" : ObjectId("5a9a09a3b1489e70f3a89a0e"), "name" : "Amy", "age" : 16, "sex" : "male" }

删除其中一条：

> db.students.remove({name:"oldhu"})
WriteResult({ "nRemoved" : 1 })
> db.students.find()
{ "_id" : ObjectId("5a9a01c5b1489e70f3a89a0c"), "name" : "Jackchen", "age" : 21, "sex" : "male" }
{ "_id" : ObjectId("5a9a09a3b1489e70f3a89a0e"), "name" : "Amy", "age" : 16, "sex" : "male" }

删除全部：

> db.students.remove({})
WriteResult({ "nRemoved" : 2 })
> db.students.find()
>

 练习

1、创建一个学生信息表（包含：姓名，性别，成绩，年龄）

2、写入十五条不同的数据

3、查询所有的男生数据（只需要学生的姓名和年龄）

4、查询成绩合格的学生信息（学生成绩大于或等于60分）

5、查询所有18岁的男生和16岁的女生的数据

6、按照学生的年龄进行排序

7、将所有的学生年龄增加一岁

步骤1和2、

先在文本编辑器里面编辑好文档，推荐使用sublimeText3或者Notepad＋＋

> use students;
> db.students.insertMany(
... [
... {name:"bob",age:14,sex:"male",grade:95},
... {name:"ahn",age:18,sex:"female",grade:45},
... {name:"xi",age:15,sex:"male",grade:75},
... {name:"hiy",age:23,sex:"male",grade:85},
... {name:"young",age:21,sex:"male",grade:45},
... {name:"nive",age:25,sex:"female",grade:55},
... {name:"longsi",age:19,sex:"male",grade:95},
... {name:"puki",age:16,sex:"female",grade:95},
... {name:"bbc",age:26,sex:"male",grade:95},
... {name:"hippop",age:54,sex:"male",grade:95},
... {name:"sue",age:21,sex:"feale",grade:95},
... {name:"yang",age:36,sex:"male",grade:95}
... ]
... )
{
        "acknowledged" : true,
        "insertedIds" : [
                ObjectId("5a9a10adb1489e70f3a89a0f"),
                ObjectId("5a9a10adb1489e70f3a89a10"),
                ObjectId("5a9a10adb1489e70f3a89a11"),
                ObjectId("5a9a10adb1489e70f3a89a12"),
                ObjectId("5a9a10adb1489e70f3a89a13"),
                ObjectId("5a9a10adb1489e70f3a89a14"),
                ObjectId("5a9a10adb1489e70f3a89a15"),
                ObjectId("5a9a10adb1489e70f3a89a16"),
                ObjectId("5a9a10adb1489e70f3a89a17"),
                ObjectId("5a9a10adb1489e70f3a89a18"),
                ObjectId("5a9a10adb1489e70f3a89a19"),
                ObjectId("5a9a10adb1489e70f3a89a1a")
        ]
}
> db.students.find()
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a0f"), "name" : "bob", "age" : 14, "sex" : "male", "grade" : 95 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a10"), "name" : "ahn", "age" : 18, "sex" : "female", "grade" : 45 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a11"), "name" : "xi", "age" : 15, "sex" : "male", "grade" : 75 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a12"), "name" : "hiy", "age" : 23, "sex" : "male", "grade" : 85 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a13"), "name" : "young", "age" : 21, "sex" : "male", "grade" : 45 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a14"), "name" : "nive", "age" : 25, "sex" : "female", "grade" : 55 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a15"), "name" : "longsi", "age" : 19, "sex" : "male", "grade" : 95 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a16"), "name" : "puki", "age" : 16, "sex" : "female", "grade" : 95 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a17"), "name" : "bbc", "age" : 26, "sex" : "male", "grade" : 95 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a18"), "name" : "hippop", "age" : 54, "sex" : "male", "grade" : 95 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a19"), "name" : "sue", "age" : 21, "sex" : "feale", "grade" : 95 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a1a"), "name" : "yang", "age" : 36, "sex" : "male", "grade" : 95 }

步骤3、

> db.students.find({sex:'male'},{name:1,age:1,_id:0})
{ "name" : "bob", "age" : 14 }
{ "name" : "xi", "age" : 15 }
{ "name" : "hiy", "age" : 23 }
{ "name" : "young", "age" : 21 }
{ "name" : "longsi", "age" : 19 }
{ "name" : "bbc", "age" : 26 }
{ "name" : "hippop", "age" : 54 }
{ "name" : "yang", "age" : 36 }

步骤4、

>  db.students.find({grade:{'$gte':60}})
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a0f"), "name" : "bob", "age" : 14, "sex" : "male", "grade" : 95 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a11"), "name" : "xi", "age" : 15, "sex" : "male", "grade" : 75 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a12"), "name" : "hiy", "age" : 23, "sex" : "male", "grade" : 85 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a15"), "name" : "longsi", "age" : 19, "sex" : "male", "grade" : 95 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a16"), "name" : "puki", "age" : 16, "sex" : "female", "grade" : 95 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a17"), "name" : "bbc", "age" : 26, "sex" : "male", "grade" : 95 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a18"), "name" : "hippop", "age" : 54, "sex" : "male", "grade" : 95 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a19"), "name" : "sue", "age" : 21, "sex" : "feale", "grade" : 95 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a1a"), "name" : "yang", "age" : 36, "sex" : "male", "grade" : 95 }

步骤5、

> db.students.find({'$or':[{sex:'male',age:18},{sex:'female',age:16}]})
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a16"), "name" : "puki", "age" : 16, "sex" : "female", "grade" : 95 }

步骤6、（升序）

> db.students.find().sort({age:1})
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a0f"), "name" : "bob", "age" : 14, "sex" : "male", "grade" : 95 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a11"), "name" : "xi", "age" : 15, "sex" : "male", "grade" : 75 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a16"), "name" : "puki", "age" : 16, "sex" : "female", "grade" : 95 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a10"), "name" : "ahn", "age" : 18, "sex" : "female", "grade" : 45 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a15"), "name" : "longsi", "age" : 19, "sex" : "male", "grade" : 95 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a13"), "name" : "young", "age" : 21, "sex" : "male", "grade" : 45 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a19"), "name" : "sue", "age" : 21, "sex" : "feale", "grade" : 95 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a12"), "name" : "hiy", "age" : 23, "sex" : "male", "grade" : 85 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a14"), "name" : "nive", "age" : 25, "sex" : "female", "grade" : 55 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a17"), "name" : "bbc", "age" : 26, "sex" : "male", "grade" : 95 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a1a"), "name" : "yang", "age" : 36, "sex" : "male", "grade" : 95 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a18"), "name" : "hippop", "age" : 54, "sex" : "male", "grade" : 95 }

（降序）

> db.students.find().sort({age:-1})
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a18"), "name" : "hippop", "age" : 54, "sex" : "male", "grade" : 95 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a1a"), "name" : "yang", "age" : 36, "sex" : "male", "grade" : 95 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a17"), "name" : "bbc", "age" : 26, "sex" : "male", "grade" : 95 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a14"), "name" : "nive", "age" : 25, "sex" : "female", "grade" : 55 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a12"), "name" : "hiy", "age" : 23, "sex" : "male", "grade" : 85 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a13"), "name" : "young", "age" : 21, "sex" : "male", "grade" : 45 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a19"), "name" : "sue", "age" : 21, "sex" : "feale", "grade" : 95 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a15"), "name" : "longsi", "age" : 19, "sex" : "male", "grade" : 95 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a10"), "name" : "ahn", "age" : 18, "sex" : "female", "grade" : 45 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a16"), "name" : "puki", "age" : 16, "sex" : "female", "grade" : 95 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a11"), "name" : "xi", "age" : 15, "sex" : "male", "grade" : 75 }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a0f"), "name" : "bob", "age" : 14, "sex" : "male", "grade" : 95 }

步骤7、（使用修改器来更新）

例子：将所有集合增加一个address项，值是‘---’

> db.students.update({},{'$set':{address:'---'}},{multi:true})
WriteResult({ "nMatched" : 12, "nUpserted" : 0, "nModified" : 12 })
> db.students.find()
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a0f"), "name" : "bob", "age" : 14, "sex" : "male", "grade" : 95, "address" : "---" }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a10"), "name" : "ahn", "age" : 18, "sex" : "female", "grade" : 45, "address" : "---" }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a11"), "name" : "xi", "age" : 15, "sex" : "male", "grade" : 75, "address" : "---" }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a12"), "name" : "hiy", "age" : 23, "sex" : "male", "grade" : 85, "address" : "---" }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a13"), "name" : "young", "age" : 21, "sex" : "male", "grade" : 45, "address" : "---" }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a14"), "name" : "nive", "age" : 25, "sex" : "female", "grade" : 55, "address" : "---" }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a15"), "name" : "longsi", "age" : 19, "sex" : "male", "grade" : 95, "address" : "---" }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a16"), "name" : "puki", "age" : 16, "sex" : "female", "grade" : 95, "address" : "---" }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a17"), "name" : "bbc", "age" : 26, "sex" : "male", "grade" : 95, "address" : "---" }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a18"), "name" : "hippop", "age" : 54, "sex" : "male", "grade" : 95, "address" : "---" }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a19"), "name" : "sue", "age" : 21, "sex" : "feale", "grade" : 95, "address" : "---" }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a1a"), "name" : "yang", "age" : 36, "sex" : "male", "grade" : 95, "address" : "---" }

所有学生年龄增加一岁：

> db.students.update({},{'$inc':{age:1}},{multi:true})
WriteResult({ "nMatched" : 12, "nUpserted" : 0, "nModified" : 12 })
> db.students.find()
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a0f"), "name" : "bob", "age" : 15, "sex" : "male", "grade" : 95, "address" : "---" }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a10"), "name" : "ahn", "age" : 19, "sex" : "female", "grade" : 45, "address" : "---" }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a11"), "name" : "xi", "age" : 16, "sex" : "male", "grade" : 75, "address" : "---" }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a12"), "name" : "hiy", "age" : 24, "sex" : "male", "grade" : 85, "address" : "---" }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a13"), "name" : "young", "age" : 22, "sex" : "male", "grade" : 45, "address" : "---" }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a14"), "name" : "nive", "age" : 26, "sex" : "female", "grade" : 55, "address" : "---" }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a15"), "name" : "longsi", "age" : 20, "sex" : "male", "grade" : 95, "address" : "---" }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a16"), "name" : "puki", "age" : 17, "sex" : "female", "grade" : 95, "address" : "---" }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a17"), "name" : "bbc", "age" : 27, "sex" : "male", "grade" : 95, "address" : "---" }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a18"), "name" : "hippop", "age" : 55, "sex" : "male", "grade" : 95, "address" : "---" }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a19"), "name" : "sue", "age" : 22, "sex" : "feale", "grade" : 95, "address" : "---" }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a1a"), "name" : "yang", "age" : 37, "sex" : "male", "grade" : 95, "address" : "---" }

所有女学生年龄增加一岁：

> db.students.update({sex:"female"},{'$inc':{age:1}},{multi:true})
WriteResult({ "nMatched" : 3, "nUpserted" : 0, "nModified" : 3 })
> db.students.find({sex:"female"})
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a10"), "name" : "ahn", "age" : 20, "sex" : "female", "grade" : 45, "address" : "---" }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a14"), "name" : "nive", "age" : 27, "sex" : "female", "grade" : 55, "address" : "---" }
{ "_id" : ObjectId("5a9a10adb1489e70f3a89a16"), "name" : "puki", "age" : 18, "sex" : "female", "grade" : 95, "address" : "---" }

 MongoDB数据库可视化工具

这里用的是Robo 3T，可以方便查看数据库，以及实现增删改查操作

人生苦短，何不用python
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原文地址：https://www.cnblogs.com/yqpy/p/8495945.html