MongoDB學習筆記

mongoDB學習網站

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

mongoDB語法

使用數據庫

use test

刪除數據庫

db.dropDatabase()

查看數據庫

show dbs

創建集合
_id是mongoDB當中默認的自增主鍵

刪除集合

db.collection.drop()

插入數據

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
        }
    ]
})

查詢語句

查詢所有記錄
select * from post

pretty()函數只是讓記錄顯示的有格式

db.post.find().pretty()

select * from post where likes = 20;

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

只顯示指定的字段，在mongoDB第二個參數中指定，1表示顯示，0表示不顯示
select title, by from post;

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

mysql的分頁
select * from post limit 1

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

skip 跳過文檔數
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語句**
select * from post where likes = 20 and by = “tutorials yiibai”

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

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

使用$or對象，裏面是一個數組

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 語句

默認只修改單一的文件
update post set title = “new MongoDB Tutorial” where title = “monogoDb Overview”

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

修改多個，例如，如果有多個文檔的條件滿足title=mongoDb Overview,上面的操作默認值更新第一個文檔
下面這種方式會將所有滿足條件的所有文檔全部更新

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

修改多列的數據

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

delete 語句

mongoDb當中的刪除操作是remove

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

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

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