python做前端mongodb_python-mongodb基本操作都在这了

数据库

增

use db1#有则切换，无则新增

查

show dbs#查看所有

db #当前

删

db.dropDatabase()

集合：

增:

db.user

db.user.info

db.user.auth

查看

show collections

show tables

删

db.user.info.drop()

文档：

增

db.user.insert({"_id":1,"name":"egon"})

user0={"name":"egon","age":10,'hobbies':['music','read','dancing'],'addr':{'country':'China','city':'BJ'}

}

db.user.insert(user0)

db.user.insertMany([user1,user2,user3,user4,user5])

db.t1.insert({"_id":1,"a":1,"b":2,"c":3})#有相同的_id则覆盖，无相同的_id则新增，必须指定_id

db.t1.save({"_id":1,"z":6})

db.t1.save({"_id":2,"z":6})

db.t1.save({"z":6})

save与insert的区别:

若新增的数据中存在主键 ，insert() 会提示错误，而save() 则更改原来的内容为新内容。

如：

已存在数据：  {_id : 1, " name " : " n1 " }，再次进行插入操作时，

insert({_id : 1, " name " : " n2 " })    会报主键重复的错误提示

save({ _id : 1, " name " : " n2 " })     会把 n1 修改为  n2  。

相同点：

若新增的数据中没有主键时，会增加一条记录。

已存在数据：  { _id : 1, " name " : " n1 " }，再次进行插入操作时，

insert({ " name " : " n2 " })    插入的数据因为没有主键，所以会增加一条数据

save({  " name " : " n2 " })   增加一条数据。

查

比较运算：=，!=,>,=,<=

#1、select * from db1.user where id = 3

db.user.find({"_id":3})#2、select * from db1.user where id != 3

db.user.find({"_id":{"$ne":3}})#3、select * from db1.user where id > 3

db.user.find({"_id":{"$gt":3}})#4、select * from db1.user where age < 3

db.user.find({"age":{"$lt":3}})#5、select * from db1.user where id >= 3

db.user.find({"_id":{"$gte":3}})#6、select * from db1.user where id <= 3

db.user.find({"_id":{"$lte":3}})#逻辑运算:$and,$or,$not

#1 select * from db1.user where id >=3 and id <=4;

db.user.find({"_id":{"$gte":3,"$lte":4}})#2 select * from db1.user where id >=3 and id <=4 and age >=40;

db.user.find({"_id":{"$gte":3,"$lte":4},"age":{"$gte":40}

})

db.user.find({"$and":[

{"_id":{"$gte":3,"$lte":4}},

{"age":{"$gte":40}}

]})#3 select * from db1.user where id >=0 and id <=1 or id >=4 or name = "yuanhao";

db.user.find({"$or":[

{"_id":{"$lte":1,"$gte":0}},

{"_id":{"$gte":4}},

{"name":"yuanhao"}

]})#4 select * from db1.user where id % 2 = 1;

db.user.find({"_id":{"$mod":[2,1]}})

db.user.find({"_id":{"$not":{"$mod":[2,1]}}

})#成员运算:$in,$nin

db.user.find({"name":{"$in":["alex","egon"]}})

db.user.find({"name":{"$nin":["alex","egon"]}})#正则匹配

select * from db1.user where name regexp "^jin.*?(g|n)$";

db.user.find({"name":/^jin.*?(g|n)$/i

})#查看指定字段

select name,age from db1.user where name regexp "^jin.*?(g|n)$";

db.user.find({"name":/^jin.*?(g|n)$/i

},

{"_id":0,"name":1,"age":1}

)#查询数组相关

db.user.find({"hobbies":"dancing"})

db.user.find({"hobbies":{"$all":["dancing","tea"]}

})

db.user.find({"hobbies.2":"dancing"})

db.user.find(

{},

{"_id":0,"name":0,"age":0,"addr":0,"hobbies":{"$slice":[1,2]},

}

)

db.user.find(

{},

{"_id":0,"name":0,"age":0,"addr":0,"hobbies":{"$slice":2},

}

)

db.user.find(

{"addr.country":"China"}

)

db.user.find().sort({"_id":1,"age":-1})

db.user.find().limit(2).skip(0)

db.user.find().limit(2).skip(2)

db.user.find().limit(2).skip(4)

db.user.find().distinct()

改

一 语法：

db.table.update(

条件,

修改字段,

其他参数

)

update db1.t1 set id=10 where name="egon";

db.table.update(

{},

{"age":11},

{"multi":true,"upsert":true

}

)

1、update db1.user set age=23,name="武大郎" where name="wupeiqi";#覆盖式

db.user.update(

{"name":"wupeiqi"},

{"age":23,"name":"武大郎"}

)#局部修改:$set

db.user.update(

{"name":"alex"},

{"$set":{"age":73,"name":"潘金莲-alex"}}

)#改多条

db.user.update(

{"_id":{"$gte":1,"$lte":2}},

{"$set":{"age":53,}},

{"multi":true}

)#有则修改，无则添加

db.user.update(

{"name":"EGON"},

{"$set":{"name":"EGON","age":28,}},

{"multi":true,"upsert":true}

)#修改嵌套文档

db.user.update(

{"name":"潘金莲-alex"},

{"$set":{"addr.country":"Japan"}}

)#修改数组

db.user.update(

{"name":"潘金莲-alex"},

{"$set":{"hobbies.1":"Piao"}}

)#删除字段

db.user.update(

{"name":"潘金莲-alex"},

{"$unset":{"hobbies":""}}

)2、$inc

db.user.update(

{},

{"$inc":{"age":1}},

{"multi":true}

)

db.user.update(

{},

{"$inc":{"age":-10}},

{"multi":true}

)3、$push, $pop $pull

db.user.update(

{"name":"yuanhao"},

{"$push":{"hobbies":"tangtou"}},

{"multi":true}

)

db.user.update(

{"name":"yuanhao"},

{"$push":{"hobbies":{"$each":["纹身","抽烟"]}}},

{"multi":true}

)#从头删-1，从尾删1

db.user.update(

{"name":"yuanhao"},

{"$pop":{"hobbies":-1}},

{"multi":true}

)

db.user.update(

{"name":"yuanhao"},

{"$pop":{"hobbies":1}},

{"multi":true}

)#按条件删

db.user.update(

{"name":"yuanhao"},

{"$pull":{"hobbies":"纹身"}},

{"multi":true}

)#3、$addToSet

db.t3.insert({"urls":[]})

db.t3.update(

{},

{"$addToSet":{"urls":{"$each":["http://www.baidu.com","http://www.baidu.com","http://www.baidu.com","http://www.baidu.com","http://www.baidu.com"]}}},

{"multi":true}

)

删

db.user.deleteOne({"_id":{"$gte":3}})

db.user.deleteMany({"_id":{"$gte":3}})

db.user.deleteMany({})

聚合

一：$match

例：

select postfrom db1.emp where age > 20 group by post having avg(salary) > 10000;#$match

#1、select * from db1.emp where age > 20

db.emp.aggregate({"$match":{"age":{"$gt":20}}})#$group

#2、select post from db1.emp where age > 20 group by post;

db.emp.aggregate(

{"$match":{"age":{"$gt":20}}},{"$group":{"_id":"$post"}})#3、select post,avg(salary) as avg_salary from db1.emp where age > 20 group by post;

db.emp.aggregate(

{"$match":{"age":{"$gt":20}}},

{"$group":{"_id":"$post","avg_salary":{"$avg":"$salary"}}}

)#select post from db1.emp where age > 20 group by post having avg(salary) > 10000;

db.emp.aggregate(

{"$match":{"age":{"$gt":20}}},

{"$group":{"_id":"$post","avg_salary":{"$avg":"$salary"}}},

{"$match":{"avg_salary":{"$gt":10000}}}

)

二： 投射

{"$project":{"要保留的字段名":1,"要去掉的字段名":0,"新增的字段名":"表达式"}}

例1：

db.emp.aggregate(

{"$project":{"_id":0,"name":1,"post":1,"annual_salary":{"$multiply":[12,"$salary"]}}},

{"$group":{"_id":"$post","平均年薪":{"$avg":"$annual_salary"}}},

{"$match":{"平均年薪":{"$gt":1000000}}},

{"$project":{"部门名":"$_id","平均年薪":1,"_id":0}}

)

例2：

db.emp.aggregate(

{"$project":{"_id":0,"name":1,"hire_period":{"$subtract":[new Date(),"$hire_date"]}}}

)

db.emp.aggregate(

{"$project":{"_id":0,"name":1,"hire_year":{"$year":"$hire_date"}}}

)

db.emp.aggregate(

{"$project":{"_id":0,"name":1,"hire_period":{"$subtract":[{"$year":new Date()},{"$year":"$hire_date"}]}}}

)

例3：

db.emp.aggregate(

{"$project":{"_id":0,"new_name":{"$toUpper":"$name"},}}

)

db.emp.aggregate(

{"$match":{"name":{"$ne":"egon"}}},

{"$project":{"_id":0,"new_name":{"$concat":["$name","_SB"]},}}

)

db.emp.aggregate(

{"$match":{"name":{"$ne":"egon"}}},

{"$project":{"_id":0,"new_name":{"$substr":["$name",0,3]},}}

)

三：{"$group":{"_id":分组字段,"新的字段名":聚合操作符}}#select post,max,min,sum,avg,count,group_concat from db1.emp group by post;

db.emp.aggregate(

{"$group":{"_id":"$post","max_age":{"$max":"$age"},"min_id":{"$min":"$_id"},"avg_salary":{"$avg":"$salary"},"sum_salary":{"$sum":"$salary"},"count":{"$sum":1},"names":{"$push":"$name"}

}

}

)

四：排序：$sort、限制：$limit、跳过：$skip

db.emp.aggregate(

{"$match":{"name":{"$ne":"egon"}}},

{"$project":{"_id":1,"new_name":{"$substr":["$name",0,3]},"age":1}},

{"$sort":{"age":1,"_id":-1}},

{"$skip":5},

{"$limit":5}

)#补充

db.emp.aggregate({"$sample":{"size":3}}) #随机选取3个文档