convert relational database to mongodb

Tags: other extensibility Pymongo Distributed document Database Mon JSON REM officialThe MongoDB database is second only to HTML5 in the 10 skills required by software developers in the big data era, according to an authoritative survey. MongoDB is a document database based

The most important role of the index is to improve query performance in query, if there is no index, MongoDB need to scan the entire collection all documents, and filter eligible document, if the index, Then query only needs to traverse the index of the limited index entries, and the index of the entries are sorted, which is also good for the "order by" operation. Index: A special data structure that stores a small portion of the data in a table to en

Index: A special data structure that stores a small portion of the data in a table to enable quick queries Advantages: 1, greatly reducing the amount of data the server needs to scan 2, the index can help the server avoid sorting or use temporary tables 3, the index can convert random io to sequential IO Index Evaluation: Samsung (very good) One star: Index if the relevant records can be placed together Two stars: The order of the data stored i

"});Db.optopiclog.ensureIndex ({"TopicID": 1, "UpdateTime":-1},{"name": "Optopicidlog_topicid_index"});9. Add users to Operationlog,1) MONGO2) Use admin;3) Db.auth (' Mongouser ', ' 123456! ');4) Use Operationlog5) Db.adduser (' Mongouser ', ' 123456! ');10. Other Commands:MongoUse Operationlog;Db.auth (' Mongouser ', ' 123456! ');Show DBS: Display Database listShow Collections: Displays a collection in the current

MongoDB installation will not say, please refer to: CentOS Yum installation mongodb and PHP extension One, create, switch, delete database [Root@localhost zhangy]# MONGO MongoDB shell version:2.4.6 connecting To:tank > Use test //Create or toggle number According to the library switched to DB Test > D

First, NoSQLLearn about MongoDB before you know that Nosql,nosql is not the only SQL abbreviation. Consists of storage and retrieval techniques that provide a restrictive model that lacks SQL relational databases. It is primarily simplified design, horizontal scaling, and finer control over the availability of data. NoSQL has a variety of technologies such as the key-value structure of REDIS, the column str

, throws an exception level. > Db.person.insert ({name: ' Xhj ', age:30})Writeresult ({"ninserted": 1})> Db.person.insert ({name: ' Zzj ', age:30})Writeresult ({"ninserted": 1})> Db.person.find (){"_id": ObjectId ("592ffd872108e8e79ea902b0"), "name": "ZJF", "Age": 30}{"_id": ObjectId ("592ffe972108e8e79ea902b1"), "name": "Xhj", "Age": 30}{"_id": ObjectId ("592ffe972108e8e79ea902b2"), "name": "Zzj", "Age": 30}// Update Age for the (It's been another year)> db.person.update ({age:30},{$set: {

(' My MongoDB connection success!!! ') }) //Case of Connection exceptionMongoose.connection.on (' Error ',function(er) {console.log (' Connection error: ' +er); }) //Connection DisconnectMongoose.connection.on (' Disconnected ',function() {Console.log (' Mongogdb disconnection ')}) Module.exports= Mongoose; Two: Create a data modelCreate a schema (a bit like creating an instance property) and create a model Get the connection var mongoose = requir