MongoDB学习笔记

mongoDB学习网站

http://www.yiibai.com/mongodb/mongodb_indexing.html

mongoDB语法

使用数据库

use test

删除数据库

db.dropDatabase()

查看数据库

show dbs

创建集合
_id是mongoDB当中默认的自增主键

删除集合

db.collection.drop()

插入数据

db.post.insert({    title:"mongoDb Overview",    description: "MongoDB is no sql databases",    by: "tutorials yiibai",    url:"www.yiibai.com",    tags:['mongoDB', 'database', 'NoSQL'],    likes:100},{    title:"NoSQL Database",    description:"NoSQL database dosedsdsds",    by:"tutorial yiibai",    url:"www.yiibai.com",    tags:['mongodb', 'database', 'NoSQL'],    likes:20,    comments:[        {            user:"user1",            message:"My first comment",            dateCreated:new Date(2013, 11, 10, 2, 35),            like:0        }    ]})

查询语句

查询所有记录
select * from post

pretty()函数只是让记录显示的有格式

db.post.find().pretty()

select * from post where likes = 20;

db.post.find({"likes":"20"})

只显示指定的字段，在mongoDB第二个参数中指定，1表示显示，0表示不显示
select title, by from post;

db.post.find({}, {"title":1, _id:0})

mysql的分页
select * from post limit 1

db.post.find().limit(1)

skip 跳过文档数
select * from post where id > 2 limit 1

db.post.find().limit(1).skip(1)

排序,1:升序，-1：降序
升序
select * from post order by asc

db.post.find().sort(1)

降序
select * from post order by desc

db.post.find().sort(-1)

rmdb（relationship manager database）中的and语句**
select * from post where likes = 20 and by = “tutorials yiibai”

db.post.find({"likes":20, "by":"tutorials yiibai"})

rmdb中的or语句
select * from post where likes = 20 or by = “tutorials yiibai”

使用$or对象，里面是一个数组

db.post.find( {    $or:[        {"likes":20},        {"by":"tutrials yiibai"}    ]})

rmdb中and和or嵌套使用
select * from post where likes = 20 and (by = “yiibai” or title=”MongoDB Overview”)

db.post.find({    "likes":20,    $or:[        {"by":"yiibai"},        {"title":"MongoDB Overview"}    ]})

updapte 语句

默认只修改单一的文件
update post set title = “new MongoDB Tutorial” where title = “monogoDb Overview”

db.post.update({"title", "mongoDb Overview"}, {$set:{"title":"new MongoDB Tutorial"}})

修改多个，例如，如果有多个文档的条件满足title=mongoDb Overview,上面的操作默认值更新第一个文档
下面这种方式会将所有满足条件的所有文档全部更新

db.post.update({"title", "mongoDb Overview"}, {$set:{"title":"new MongoDB Tutorial"}}, {multi:true})

修改多列的数据

db.post.update({"title", "new MongoDB Tutorial"}, {$set:{"title":"MongoDB Tutorial", "decription":"I'm mongoDb"}})

delete 语句

mongoDb当中的删除操作是remove

db.post.remove({"title":"MongoDB Tutorial"})

mongoDB聚合函数
select title from post group by title;

db.post.aggregate([{$group: {_id:"$title", desciption:"$description"}}])