MongoDB

Cause: After installing the MongoDB, want to open the page end controller to look, found http://127.0.0.1:28017/_commands this link can not open, the hint rest does not open, You need to add a configuration at startup--restSolve: SC Delete

The contents are as follows: Use Demodb//using DEMODB, the following hypothetical Operation collection is Foo 2 Db.foo.remove ({"id": "Bar"})//delete a piece of data 3 Db.foo.remove (

DBObject o= (dbobject) Json.parse ("{groups.groupname: ' group1 '}"); DBObject o2= (dbobject) Json.parse ("{groups.size:0}"); This extra part is filed selection, for 0 you see the result inside there is no this filed, if 1 is only this filed is

Because do not enter the database, this article does not represent MongoDB performance, only in this and IO to do a simple comparison of the performance is not scientific, but also from the side to explain a certain problem, to the development of a

The biggest advantage of the NoSQL database is that it supports the cluster well, and today it is ready to use MongoDB to configure a master-slave server. About the installation of MongoDB is not introduced, I use the Mac side of the MongoDB,

To get data in groups: Db.express_info.group ({"key": {"Express_code": true}, "initial": {"num": "0", "mobile": "0"}, "reduce": function (Doc, Result) {result.num++, result.mobile=doc.mobile}, ' condition ': {' mobile ': ' 18663930231 '}, '

This article records the basic operation of MongoDB, this is only the most basic, so it should be mastered. Database A database is a collection of physical containers. Each database has its own set of files on the file system. A single MongoDB

Question: Require auth data to have schema version 3 but found 1This is the link that can be viewed as follows:Http://stackoverflow.com/questions/26723693/getting-an-error-trying-to-add-a-user-to-mongodb-2-6-5In short, Use admin

background Recently the business MONGO upgrade, because the need to adjust the business code and offline testing, the work lasted one months before the results of the phase. Version upgrade be sure to make a version upgrade on the production

Installation Instructions System Environment: Centos-6.3Installation software: mongodb-linux-x86_64-2.2.2.tgzDownload Address: Http://www.mongodb.org/downloadsInstallation machine: 192.168.15.237Upload location:/usr/local/Software Installation

What's the matter MongoDB. MongoDB is written by the C + + language and is an open source database system based on distributed file storage. In the case of high load, adding more nodes can guarantee the performance of the server. MongoDB is designed

When MongoDB stores the time type data, it is converted to UTC time, then stored in the database, and when we take out the stored time, there is the problem of jet lag. For example, we use the Beijing time, read the value will see the current time

MongoDB ShardShardingIn MongoDB there is another cluster, that is, the Shard technology, can meet the requirements of a large number of MONGODB data volume growth.When MongoDB stores massive amounts of data, a machine may not be enough to store data,

MongoDB Start Stop methodThe official website installs the introduction to still have the way that starts to stop1 startsudo service Mongod start2 stopsudo service Mongod stop3 restartsudo service mongod restart4 Viewing statussudo service Mongod

In fact, I always want to tidy up the MongoDB database I often use some operations command, finally have time ~MongoDB is an open source, free, non-relational database (NOSQL) with no tables, no records, and some differences from the usual

Environment:Centos 7.5 1804MongoDB 4.0.1shard分片主机： shard1: IP:192.168.1.1 shard2: IP:192.168.1.2 shard2: IP:192.168.1.3 #三台主机分别启动三个mongod实例： mongod1: 端口: 27017 mongod2: 端口: 27018 mongod2: 端口: 27019configsrv主机： IP:1

ReasonMongoDB will save the fragmented collection in the Config.collection collection, and if you need to see the Shard key, you need to find it based on that collection. Many other official Shard shortcut commands are also in the Config

Now learn more about MongoDB's database operations.Query statementsDb.xxx (collection name). Find () # query Db.xxx (collection name). FindOne () # returns only one Db.xxx (collection name). FindOne (). Pretty () # return result formatted #

[From: http://blog.chinaunix.net/space.php? Uid = 7907749 & Do = Blog & id = 2037221]  I am preparing to send free time to MongoDB research recently, so there will be a series of articles to record this process. Download the Windows 32 version 1.2.1:

Mongo is a database developed for three years. I have never heard of it. This is not a new company. I can't figure it out. The database chooses a Mongo. First, I have no idea about Mongo's security, performance, and data size. He has little