create schema mongodb

MongoDB is an open-source non-sql database engine. MongoDB is extensible and is a substitute for standard relational database management systems (RDBMS). A replica set can also provide access to your data when a node fails. Install MongoDB 1. Ensure that each member of the replica set is set hostnameNano/etc/hostname/etc/hostname:Europa 2.

Tags: based on the resulting record repair database technology share 3.4 concern anomaliesEBay: Using MongoDB to create business-critical multi-Datacenter applicationsAs the world's top ten retail brand, ebay has more than 170 million active users, and has 1 billion shopping lists spanning 190 markets around the world, so that on a scale, ebay is not allowed to have any downtime. That's why companies rely o

MongoDB Performance Chapter-Create indexes, composite indexes, unique indexes, delete indexes and explain execution plansFirst, the indexMongoDB provides a variety of index support, the index information is saved in System.indexes, and the default is always to create an index for _ID, its index uses the basic and MySQL and other relational database. In fact, it c

Create a collection command for MongoDB db. createCollection Create a collection command for MongoDB db. createCollection The complete command is as follows:Db. createCollection (name, {capped: , AutoIndexId: , Size: , Max }) Name: Set nameCapped: whether to enable the

Before you start using MongoDB (version:3.2.9), you must first create Database and Collection in MongoDB. Database is independent, each database has its own collections, different database, the name of the same collection can exist, but the database is not a physical storage unit, MongoDB takes collection as the physic

Tags: Ruby tutorials MongoDB Client Database connectionIn Ruby's MongoDB2.4.3 driver version, build a ruby database connection by creating a Mongo::client object. The Mongo::client constructor is available in two ways: one by providing a host list and some optional parameters, and through a connection URI. Create a good database connection by default to the admin database.1.

Tags: style blog http color io os ar using forWindows MongoDB Basic Gameplay series Introduction and installation of the Windows MongoDB Basic gameplay series Windows MONGODB Basic Gameplay series two curd operations (create, update, read and delete) Simply say a few words in

() # successfully deleted the already existing collection true> db.mycol.drop () True > show collectionscol_1col_2runoobsystem.indexes# Delete nonexistent collection, error false Use the Find command to view the contents of the document: Db.collection_name.find ()>Dbrunoob>Db.rundb.runCommand (Db.runoob>Db.runoob.find () {"_id": ObjectId ("578dc96c5dadb19a13cd905e"),"Word":"Hello","Chinese":"It's a Nice day today!","中文版":"Today the weather is well!" }>Show Collectionscol_1col_2runoobsystem.ind

based on the document you want to update. If found, the update is normal. At the same time, Upsert can not only avoid the problem of race state, but also reduce the amount of code. How to use: Set the Update method the third parameter is true. Update multiple documents By default, an update can only take effect on the first document that meets the criteria. To update multiple qualifying documents, you can set the fourth parameter of the Update method to True.Write security mechan

Tags: redis mongodb crudAfter you've installed MongoDB, you can try running the JavaScript shell.Under Mac, from the installation to the shell that can run MONGO, the steps are as follows:1. Find the website of MongoDB. Download the appropriate installation package. such as DMG under the Mac2. Unzip the installation.3. Configure the environment variables.The deta

I have a lazy idea. How should this good idea begin? Well, this is an appropriate little madness: Why not build our own MongoDB version directly on the basis of postgres? It sounds far-fetched, but it's simple and real. When the NoSQL movement was brilliant, the Postgres community did not sit around and fiddle with their thumbs. They continue to develop, throughout the Postgres ecosystem, and several prominent features have caught my eye: integrating

, it will delete the oldest record;3, limit the maximum number of sets: Db.createcollection ("Log", {max:1024}), create a name for the log collection, the maximum number of bars is 1024, more than 1024 and then insert the data will delete the oldest record. This can not use Capped:true, or will error;4, that is, limit the maximum number of bars to use space size: db.createcollection ("Log", {size:1024,max:1024}) or db.createcollection ("log", {capped:

, causing the startup difficulty.Solution SolutionsBut fortunately, finally find a solution to the problem ah. O (∩_∩) o haha ~In the MongoDB installation path, there are two files in the data file a mongod.lock and Storage.bson, generally delete mongod.lock on it, if the service error code 100 can not be resolved, the Storage.bson together with the deletion of the start can be!Suggestions:After installing MongoDB