MongoDB

MongoDB failed to start service, error code: 48,100 Figure: Solving Method 1: Delete the Mongod.lock file under Mongodb\data\db 2: Remove the previous service configuration Mongod--logpath

1, first, to MongoDB official website http://www.mongodb.org/downloads download the corresponding installation package, such as: My own version of the download 2. Establish MongoDB folders and Mongodbdata folders on disk, as shown below: 3, the

First, the database commonly used commands1. Help View command PromptCopy code code as follows: HelpDb.help ();Db.yourColl.help ();Db.youColl.find (). Help ();Rs.help ();2. Switch/CREATE DatabaseCopy code code as follows: Use YOURDB; The current

The recent need to dump some of MONGODB data to MySQL, previously only bson packets.The initial idea is to use PHP's extension bson_decode directly,Found two tricky questions, One is the memory consumption problem, if a bson more than 2M,

Query by criteriaCompare operations:$lt, $lte, $gt, $gte, $neDb.user.find ({"score": {$gt:}});$or : Contains multiple conditions, the relationship between them for or, $nor equivalent to or take the inverseDb.user.find ({$or: [{"score":

Project scenario: MONGO in the first query is very slow, the back is good. If you do not query for a long time, the next start will be very slow for the first time, so from the link at that time, to troubleshoot the final discovery or MONGO index

A database monitoring tool is essential and of course MongoDB is installed with self-monitoring.The monitoring tool Mongostat.exe and Mongotop.exe use and parameters are explained here.A. Description of the Monitoring tool:Two. Monitoring tool

In Shell operations, we can use Max or min to obtain the maximum value. Or we can use sort and limit to get the most value. It seems that Max and Min cannot be used in Java, but we can make some modifications to the latter method. DB. t1.insert ({"

1. Mongo object The Mongo object implements a connection pool. Mongo objects are thread-safe. Therefore, you can create only one Mongo object and use it safely in a multi-threaded environment. Therefore, we can use the Mongo variable as a member

1. Download the Windows version of MongoDB, including the 32-bit and 64-bit versions (of which the Linux version is also available). Download the version based on the system conditions. :Http://www.mongodb.org/downloadsHere I downloaded the

1. dbcollection Management package com.boonya.mongo;import java.util.Set;import com.mongodb.DBCollection;public class CollectionManager { public static DBCollection getDbCollection(String collectionName){ return

This article is based on a discussion on a Google forum. I would like to know the comparison of MongoDB, hadoop, and MySQL and how to use them properly. The problem is as follows: This is a discussion on the Google group of MongoDB-user. LZ is a

The first two articles reprinted the nosql article, which introduced the benefits of nosql and analyzed the advantages and disadvantages between nosql and relational databases. In fact, nothing is absolutely good, absolutely bad; as long as it is

Reprinted from nosqlfan. view the original article This article describes how to write common SQL statements in MySQL in MongoDB. If you are eager to try using MySQL for a long time, this simple article will help you enter the role more

MongoDB is a database server that can run in the previous or background mode while waiting for client connection. After you start MongoDB, you can see the following output: ~/$ ./mongod # # some logging output # Tue Mar 9 11:15:43 waiting for

Mongmongo is an ODM framework written in Java, making MongoDB operations more convenient.   Mongomongo strives to provide Java developers with functions similar to activeorm orThe Hibernate operation API retains MongoDB's schemaless, document-based

Recommended papers: momodi's Dancing Links application in search, Knuth's DLX paper, and Chen danqi's Dancing Links Application   Dancing Links is used to optimize the DFS process for a class of precise coverage issues. The exact coverage problem is

Mongodb tool: 1. mongodump and mongorestore Bson beifen 2. Export export and Export Import Multiple formats are available everywhere 3. Sniff Provides shell statements for Operations sent to the database 4. Reset stat Provide mongo status

When I first came into contact with MongoDB C ++ development, I found that the C ++ Driver source code package provided by the official team seemed to have some problems. After some hard work, I wrote down the first article here.My Development

Http://www.yzswyl.cn/blread-1444.html Note: users are added for database operations.1. Go to the database use dbname2. Adding User Permissions to the current database is for the current data1. Add and verify users> Use admin> Db. addUser ("zjx",