MongoDB

Establish the following test data to count the number of students in each class and their scores through mapreduce.The code is as follows: Public stringSumstudentscore () {varCollection = _database.getcollection ("Studentinfo"); //Group statistics

MONGO # Run the client (you can also go to the MongoDB installation directory to run this)Use admin # to switch to the System Account tableDb.system.users.find () # View current account (password has been encrypted)Db.system.users.remove ({}) #

In the MongoDB configuration file configuration described how to configure, here we are using the configuration file for Master/slave configuration implementation of Master-slave replication:First, the configuration of the master-slave server:1.

Query.all ("name","a","b");//to match an array with multiple elementsquery.in ("name","a","b");//includes all values specified, you can specify different types of conditions and valuesQuery.and (Query.eq ("name","a"), Query.eq

First, configure the environment1. Two CentOS server with MongoDB installed; (Installation reference http://281816327.blog.51cto.com/907015/1598270)2. The IP of two servers is 192.168.1.112, 192.168.1.113 respectively;3. Two server firewalls let go

MONGO official website Http://www.mongodb.org/downloadsVue Tools Download http://www.mongovue.com/downloads/Build a folder, put the extracted MONGO file, in the new one put the specified databaseMake a variable, specify binThe following folders and

Win+r into the DOS command window, enter cmd, enter the directory of the MongoDB EXE file, such as my E:\MongoDB\bin, respectively, execute: "E:" carriage return, then: "CD Mongodb/bin" enterEnter "MONGO" and start working on the database, I use the

MongoDB supports failover and implementation redundancy across multiple machines through asynchronous replication. Only one machine is used for write operations at the same time in multiple machines, and because of this, MongoDB provides the

Use the aggregation framework to transform and combine documents in a collection. Create a pipeline (pipeline) with multiple artifacts for processing a series of documents. These artifacts include:Filter (filtering)Projection (projecting)Grouping

Use the Ensureindex function to create an index of the collection.For collections, each index needs to be created once, and duplicate creation has no effect;> Show Collections System.indexes UsersThe index metadata of all the databases is stored in

MongoDB in Find query using Perl-compatible regular expressionsPerl Express Description: Http://www.chinaunix.net/old_jh/25/159388.htmlExample:> db.post.find ()    {  "_id"  : objectid ("54a530c3ff0df3732bac1681"),  "id"  : 2,  "name"  :  "Joe", 

1. Provision and installation of resources (Ayjs.net) Learning instructions: Nodejs is still operating in a non-Windows environment, so everything is Current time: December 06, 2014 Aaronyang Website address: www.mongodb.org Document

MongoDB uses find to query, returning a subset of the documents in a collection;Returns all documents in the Document collection blog:> Db.post.find () {"_id": ObjectId ("54a530c3ff0df3732bac1681"), "id": 2, "name": "Joe", "age": +, "sex": 1,

# # #安装1. Install (Windows): Unzip to install directory C:\mongodb, create folder C:\mongodb\data\db, C:\mongodb\data\log, create file c:\mongodb\data\log\ MongoDB.log2. Start-Up service: CD C:\mongodb\bin; Mongod-dbpath "C:\mongodb\data\db"3. Test

Read the previous article, I believe everyone will know how to open MongoDB, this article on the next one of the additions and deletions to change, first when we use the same way to open MongoDB, suddenlyDumbfounded, wipe, unexpectedly open,

OverviewMongoDB can use the standard method to implement log rotation, that is, to get to the current log and open a new one. To implement it, the Mongod instance renames the current log file by adding a UTC (GMT) timestamp at the end of the file

Use the following command to install MongoDB as a Windows service. The author's MongoDB directory is D:\Program files\mongodbSwitch to D:\Program files\mongodb\bin>Mongod--logpath "D:\Program files\mongodb\data\logs.txt"--logappend--dbpath

MANGODB Installation1. Download the MongoDB installation file that I installed for Windows 64-bit, as follows:Https://fastdl.mongodb.org/win32/mongodb-win32-x86_64-2008plus-2.6.6-signed.msi2. Create a new MongoDB folder on e-disk (casually put, such

I. Approximate INTRODUCTION MongoDB-Distributed Document store database Mongodb, a distributed document storage database, written in the C + + language, is designed to provide scalable, high-performance data storage solutions for Web

MongoDB has successfully started in the previous post: http://blog.csdn.net/u010773667/article/details/41847487, it's time to do a series of operations. We open a cmd, enter the "MONGO" command to open the shell is MongoDB client, the default