MongoDB

Lucky to taste the mango today, found that there are many types of self-growth ID, but no long/int.One idea:1. Self-built a collection (table, assuming named: Identityentity, where Fields: _id, Key, Value, _id you know, key:collection name, need

1. IntroductionIt is a kind of database cluster system that expands the massive data horizontally, the data table is stored on each node of sharding, and the user can easily construct a distributed MongoDB cluster by simple configuration. So first

MongoDB projection means to select only the necessary data instead of selecting the entire data for a file. If a document has 5 fields, you need to display only 3, and then select only 3 fields.Find () methodMongoDB's Find () method, which is

Five: MongoDB import, export, backup, restore, user authorizationOne: Data export, data importAs a DBA (administrator), you often encounter the need to import and export data, as described in the following utilities (bring-your-own):1: Data import

Query the first document that meets the criteria (cannot be called a record for MONGO)Db. Collection_name.findone ({},{});Query for eligible documents and sort by specified criteria, skip the previous N1 documents, and return a list of up to N2

One to one relationship: Embed, such as the user information collection has an address field, the Address field has three fields of province, city and county. The modeling is as follows:650) this.width=650; "class=" Fit-image "title=" QQ2012072519004

Today suddenly the power outage caused the MongoDB shard cluster to cause this error, temporarily do not know how to solve, if someone knows please reply meAnd now put the record down and wait for the post-processing.Fri 8 10:49:52.165

MongoDB replica setup (one master and two spare)Master: 192.168.0.237Prepared 1:192.168.0.122Prepared 2:192.168.0.123Three machines are also operatedTar zxf mongodb-linux-i686-1.8.1.tgzMV

assertion:18 {code:18, ok:0.0, errmsg: "Auth Fails"}MongoDB 2.4.10 uses the Xucy administrator account under the Admin database to export the data and verify the failure.# mongoexport-uxucy-p-D test-c pro-f

Inserting more than one test data> for (i=1;i... db.blog.insert ({"title": I, "content": "MongoDB Test article. "," name ":" Liu "+i});... }Db.blog.list.find (). Limit ((). ForEach (function (data) {print ("title:" +data.title);}) Cyclic foreach

The following articles describe how to solve the incompatibility between the DB2 code page and the actual application code, the following is a detailed description of the main content of the article. I hope you will have a better understanding of it

The following articles mainly describe the actual operation solution for correctly Improving the IMPORT command performance in the DB2 database. If you are curious about the actual operation solution for correctly Improving the IMPORT command

The following articles mainly describe how to correctly use the DB2 Configuration Wizard to configure parameters. DB2 database version 8 provides a tool for automatic parameter configuration, that is, the Configuration Wizard. You can start the

The following articles mainly describe the actual operation steps of DB2 Online Incremental backup, restoration Incremental backup, and Rollback Recovery. The following describes the specific content. If you are curious, the following articles will

The following articles mainly describe the daily practical operations in the DB2 database. I saw the daily practical operations in the DB2 database on the relevant website two days ago. I thought it was good and I would like to share it with you, if

Today, we want to share with you how to improve the IMPORT command performance in the DB2 database. We all know that when we use the IMPORT Command provided by the DB2 database to IMPORT data, all constraints must be verified, and all loaded rows

The following articles mainly describe the correct installation process of DB2 PE in Linux. I saw the correct installation process of DB2 PE in the Linux operating system on the relevant website two days ago, here is a detailed description of the

This article will introduce you to the DB2 plug-in module. the DB2 plug-in module can back up and restore the DB2 database online to make the application and availability of the DB2 database more adequate. I hope this article will help you. DB2 plug-

DB2 obtains detailed information about the current user table, field, index, and so on. db2 current user Obtain detailed information about all tables, fields, and indexes. SELECT d. name tbName, COALESCE (d. remarks, '') tbDesc,. name columnName,.

You may have heard of the new DB2 Viper architecture, which supports table and hierarchical data structures. In fact, the previous article summarized the New XML features in DB2 and described how to create database objects and populate these