digitalocean mongodb

First, start the MongoDB shelltool, that is, bind the cmd.exe Common shell commands are as follows: 1. query the names of all local databases > show dbs; 2. Switch to the specified database environment (if no database is specified, a new database is created) > use dbtest; Switch to the dbtest database or create a database named dbtest.3. query all collection sets in the current database (equivalent to table) > show collections; 4. Create a collection

Mongodb Study Notes 02 and mongodb Study NotesMongodb Study Notes 02-CURD operations CURD indicates Create, Update, Read, and Delete operations. Create a database Directly use the database name and create a collection to create a database. Create collecion db.createCollection("collectionName") Create collection implicitly db.collectionName.insert({xxxxxx}) Delete collection db.collectionName.drop()

Basic use of mongoDB (II), use of mongodbConnect to the mongoDB server for basic database operations./bin/mongo 127.0.0.1: 12345View the current database> show dbsadmin (empty) local 0.078GBut change the database (it will be automatically created if it does not exist)> use jeromeswitched to db jeromeDelete database> db. dropDatabase () {"dropped": "jerome", "OK": 1}Delete table 12345678910 >>sho

Mongodb Study Notes 07: mongodb Study Notes Export export in json or csv format Using import to import json or csv Mongodump exports binary bson structure data and index information Mongorestore imports binary files Mongoexport -H host -- port number-u user name-p password-d database name-c table name-f field1, field ..... export field-q query condition-o export file name -- csv is equivalent to -- t

Mongodb Study Notes 05 and mongodb Study NotesEnable authentication Mongod does not have the permission to start by default. You need to specify-auth to start, or set security. authorization to "enabled" in the configuration file"Create user Db. createUser (user, writeConcern) Document http://docs.mongodb.org/manual/reference/method/db.createUser/#db.createUser User format { user: " WriteConcern: For exa

Function name Regexobjsubobjkeyfunction codefunction(proto,value) {varMatch=false; varReg =NewREGEXP ('. * ' +value); Print (Json.stringify ( This. obj)); Print ( This[' Arr_ ' +Proto]); for(varKeyinch This. obj[' Arr_ ' +Proto]) {print (key); if(key!= ' count ' key!= ' isgame ') {Match=reg.test (key); if(match) {return true; } } } return false;}Query DemoStreamlineDb.test.find ({$where: "Regexobjsubobjkey (' qq ', ' 1234567 ')"})StandardDb.test.find ({$and: [{arr_qq:{$exis

Tags: mongodb remove dropFirst look at the collection post Chinese file information:> Db.post.find ();{"_id": ObjectId ("54A51CFD7F46906F81B7ADCD"), "bar": "Baz"} {"_id": 0} {"_id": 1} {"_id": 2} {"_id": 5, "Test1": 0} {"_id": 4, "Test2": 2} {"_id": 3 , "Test3": 3} {"_id": 6, "TEST5": 5} {"_id": 7, "Test1": 1} {"_id": 8, "Test1": 1}Delete the specified document:> Db.post.remove ({"_id": 5});Writeresult ({"nremoved": 1}) > Db.post.find ();{"_id": Objec

To see which databases are available:Show DBSSwitch to that library:Use library name Use LocalUse also has a function of "Create a Database" Use testTo delete a database:Db.dropdatabase ();To view a collection:Show collectionsTo create a collection:Db.createcollection ("user");Implicitly created, inserted directly into the collection, she will automatically create the collectionDb. user. Insert ({ID:1, Name: "Lisi"});To delete a collection:Db. user. Drop ();Insert:Db. user. Insert ({ID:1, Name:

Tags: tags sed test data gray process localhost SSE localOne, the connection 1.mongo mongodb://localhost:27000 2. Show Databases (DBS) Use test 3. Db Show collections Second, insert 1.db.proccessedfile.insertone ({fileName: "20170403/3.gz", Processeddate:new isodate (), datanumber:10000, x:10}) 2.db.mongodb.insertmany ([{item: "Journal", Qty:25, Tags: ["blank", "red"], size: {h:14, w:21, UoM: "CM"}}, { Item: "Mat", qty:85, Tags: ["Gray"], size: {h:27.

format is Keyname1_dir1_keyname2_dir....keynamen_dirn;You can also specify an identity name:>db.users.ensureindex ({"username": 1},{"name": "FirstName"}) { "Createdcollectionautomatically" :false, "Numindexesbefore" :2, " Numindexesafter ":3," OK ":1 }>db.users.getindexes () [ { " V ":1," key ":{ "_id" NBSP;: 1}, "name" : "_id_", "ns" : "Blog.users" }, { "V" :1, "Key" :{ "Age" :1, "username" :1 }, "name" : "Age_1_username_1", "ns" : "Blog.users" },{ "V" :1, "Key" :{ "username" :1},

10) db.char.find ({' name ': ' Weixiaobao '}). Skip (2). Limit (10)f) The query returns the number of bars Db.char.find ({' name ': ' Weixiaobao '}). Count ()g) sort (by name ascending, age descending) Db.char.find (). Sort ({' name ': 1, ' age ':-1})h) Query the specified column to db.char.distinct (' name ')i) Remove the set Db.char.drop ()j) Create index Db.char.ensureIndex ({' Name ': 1, ' Age ': 1},{unique:true})k) View index db.char.getIndexes ()L) Delete index Db.char.dropIndex (' IndexN

Tags: 9.png support difference God sharing interface images PNG selectionThe user writes the data using the interface provided by the database, and the data is stored in a standard format.Different database differences: The organization of the data is different, while providing different types of queries, users according to their own needs to choose the appropriate database.You can store your geographic location in MongoDB, such as searching for nearb

": "Wangwu", "Age" : $ > Db.stud Ent.find (). Skip (3). Limit (3) "_id": 4, "name": "Zhaoliu", "Age": "_id": 5, "name": " Qianliu "," Age ": " _id ": 6," name ":" Sunba "," Age ": + > Db.student.find (). SK IP (6). Limit (3) "_id": 7, "name": 7, "Age": 70} Db. Collection name. Find (). Sort ({key: number})A number of 1 means ascending, and a number of 2 means descending > Db.student.find (). Sort ({age:1}) { "_id": 1, "name": "Zhangsan", "age": +, "sex": 1 } { "_id": 2, "name": "Lisi", "age": 2

1. Use or create a database:Use WandrecorderYou'll use the keyword to create or fetch a exicting database.2. Find all documents in the database.Db.wands.find ()You already start with DB Keywrod. Then follow your collection name, where is ' wands ', find () method would return all the documents in that collection.3. Insert document to the collections:Db.wands.insert ({name: ' Dream Bender ', Creator: ' Foxmond '})Use Insert () Metod to inserts JSON data to the collection as a document.4. Find a v

Optime: Read Oplog.rs collection. The last time the instance was changed.MongoDB uses lastheartbeat for automatic transfer.The Mongod instance sends a heartbeat packet to the other members every two seconds, and the member's state is judged by the health of the member returned in Rs.status (). If the primary node is unavailable, then all secondary nodes in the replication set will trigger an election operation. Select the new primary node. If there are multiple secondary nodes, the node that ha

before the copy is completed and then write Oplog, it is possible that the same operation will synchronize two copies, However, MongoDB at the beginning of the design to consider this problem, will oplog the same operation executed multiple times, and the effect is the same as the execution once.The growth rate of 3:oplogOplog is a fixed size, he can only save a specific number of operation logs, usually oplog use of space growth rate with the system

/*** MongoDB $type operator*/ /*** The $type operator is based on the Bson type to retrieve the matching data type in the collection and returns the result.* The types of MongoDB that can be used are shown in the following table:* Type Number Notes* Double 1* String 2* Object 3* Array 4* Binary Data 5* Undefined 6 is obsolete.* Object ID 7* Boolean 8* Date 9* Null 10* Regular Expression 11* JavaScript 13* S

Label:OverviewThis article mainly describes the method of installing MongoDB on Windows systems.MongoDB Official website: http://www.mongodb.org/, the latest version is 2.6.7.Attention:Starting with version 2.2, MongoDB does not support Windows XP. Please use the latest version of Windows to use the latest version of MongoDB.If you are running any version of Windows Server R2 or Windows 7, install the hotfi

Install MongoDB on CentOS7 Install MongoDB on CentOS7 1. Connect to the CentOS7 server through SecureCRT; 2. Go to the/usr/local/directory:Cd/usr/local 3. Create the tools directory in the current directory:Mkdir-p tools 4. Go to the tools directory:Cd tools 5 download the mongodb-linux-x86_64-rhel70-3.2.4.tgz file that matches the CentOS system:Wget https://fast

MongoDB supports multiple languages and is driven by multiple languages. Java MongoDB operations to achieve curd: premise: Download the corresponding driver: download on the official website: http://central.maven.org/maven2/org/mongodb/mongo-java-driver/ I use mongo-2.10.1.jar version: the following code in detail, each method can be executed separately. In order