MongoDB

about MongoDB's MapReduceCategory: MongoDB2012-12-06 21:378676 People read Comments (2) favorite reports MongoDB Mapreducemapreduce is a computational model that simply executes a large amount of work (data) decomposition (MAP) and then merges

1. Whether it is storing normal data or storing files, we must first visit the MongoDB database Public Static mongodatabase getdatabase () { //MongoDB server address var New mongoclient (Config.BasicConfig.DbAddress);

Before on the 32-bit Win7 on the configuration once, success, but also reference a lot of friends, but at that time the brain heat unexpectedly did not record such a tedious process ....OK, this time to be on the 64-bit machine to re-engage, before

Aggregation IntroductionThe aggregation operation is the operation that comes out of the data record and returns the computed result. MongoDB provides a rich aggregation operation to detect and execute calculations on datasets. Data aggregation

Pomelo installation is simpleNPM Remove CRCNPM install [email protected]-gdNPM Remove ExpressNPM install [email protected]-gdNPM Install MongoDB (if installation fails first NPM cache clean and try again)The version is too high and prone to problems

Data export MongoexportSuppose there's a apachelog table in the library with 2 records, and we're going to export it/test/mongodb/bin/mongouse WxdataSwitched to DB WxdataDb.apachelog. Find ();{"_id": ObjectId ("53993357e0e73ac14b29da8a"), "host": "66

Backing up and recovering data is important for managing any data storage system.1, cold backup and recovery-Create a copy of the data file (if you want to stop the MongoDB server), that is, the direct copyMongoDB stores all the data in the data

The above (http://www.cnblogs.com/guoyuanwei/p/3565088.html) describes the deployment of a default shard cluster, the MongoDB shard Cluster has a general understanding, So far we have not set up other databases on the cluster, MongoDB shards are

Java Operations on MongoDB1.1 Even single MongoDBMongo mg = newMongo ();//default 127.0.0.1 port is 27017Mongo mg = newMongo (IP);//You can specify that the IP port defaults to 27017Mongo mg = newMongo (ip,port);//can also specify IP and port number1

1. Get the latest version https://fastdl.mongodb.org/linux/mongodb-linux-x86_64-2.6.1.tgz2. Unzip and enter the bin directoryTar zxvf mongodb-linux-x86_64-2.6.1.tgzCd/opt/database/mongodb-linux-x86_64-2.6.1/bin3. Create a directory in which MongoDB

Introduction A lock is a mechanism introduced by a database to control the integrity of concurrent data. In concurrent applications, locks are not terrible. locks are generally divided into deadlock and lock wait. The deadlock is caused by two

When using the IMPORT Command provided by DB2 for data IMPORT, all constraints must be verified, all loaded rows will be logged, and the trigger will be activated, therefore, when loading a large amount of data, the performance of the IMPORT utility

This article focuses on some restrictions on the size of the DB2 Management page, which are used in real-world DB2 database applications. We generally encounter some errors because we do not know much about the limitations of the DB2 database. Here,

The following article mainly describes how to uninstall AIX from a DB2 database. I found a document on how to uninstall AIX from a DB2 database on a website, the following is a detailed description of the article, hoping to help you in this

This article mainly describes the actual operation steps for the ava XML to successfully store the DB2 code. We all know that the actual operation steps for the ava XML to successfully store the DB2 code frequently appear in practical applications,

This article describes how to easily master the actual operation steps of database memory protection in DB2 9.5. in DB2 9.5, the database engine changes from the process mode to the thread mode, which means that the entire database engine is in an

If you are curious about how DB2 creates database partitions, this article will unveil its mysteries, this article describes how to correctly create database partitions and related commands on a DB2 database for your reference. Create database

This article mainly describes the actual operation steps of the IBM DB2 package rebinding implementation, as well as the description of relevant matters worth attention in actual operations, we all know that rebinding is a process of re-generating

During the DB2 migration today, from V8.1 to V9.7, we plan to force application and make an offline backup because of version differences and the library is a development Test Library, when you use db2 force applications all in the source database

Sort out the online backup recovery steps 1. Find the database db2 list history backup all for xcldb 2. before the database is damaged, run the db2ckrst command to obtain the recovery sequence. skip this step if the database to be recovered is