mongodb remove all databases

collection, when the argument is empty, removes all indexes (except the index on _ID) Ensureindex (Keypattern[,options]) creating an index Update (Query,object[,upsert_bool,multi_bool]) updates a document in the collection that meets the criteria Find ([Query,fields]) search for documents that meet criteria based on criteria Of course there are many commands that are not listed here, but you can easily view the commands that can be

I. mongodb sharding: add and remove shards on multiple simulated nodes in win7 environment. mongodbwin7 This article describes how to simulate mongo sharding on a win7 computer. If you have multiple servers, you can deploy each mongo on a single computer. We will configure three mongo shards, three configuration servers, and one Routing Server. Configure as shown in. This section describes how to add and

Remove duplicate records from mongodb group query statistics The mongodb version is, MongoDB shell version: 2.4.4The operating environment and shell window are as follows: [mongo_user@mongodb_dbs ~]# mongo --port 30100MongoDB shell version: 2.4.4connecting to: 127.0.0.1:30000/testmongos> mongos> use posswitched to db p

Source: comparison of various nosql databases in http://hi.baidu.com/eastdoor/blog/item/758d0e3eedb5d92471cf6c14.html Cassandra, MongoDB, CouchDB, Redis, Riak, HBaseCouchDBDevelopment language: ErlangMain advantages: data consistency and ease of useLicense: ApacheProtocol: HTTP/RESTApplicable: accumulated, less changed data. Or a large number of versions are required.Example: CRM, CMS systems. multi-site de

The basic concepts in MongoDB are databases, collections, and documents .The following table will help you understand some of the concepts in MONGO more easily: SQL Terminology/Concepts Explanation/Description MongoDB Terminology/Concepts Explanation/Description Database Database Database Database

/* 1. query all databases in SQLSERVER */ Use master Go Select * from sysdatabases where dbid> 4/* The where condition is used to remove the system database */ Go /* 2. query all databases (Stored Procedures) in SQLSERVER )*/ Exec sp_helpdb /* 3. query tables in the specifie

/* 1. query all databases in sqlserver */ Use master Go Select * From sysdatabases where dbid> 4/* The where condition is used to remove the system database */ Go /* 2. query all databases (Stored Procedures) in sqlserver )*/ Exec sp_helpdb /* 3. query tables in

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 ()//delete all records in Foo, but Foo still exists, show collection can also see Foo 4 Db.foo.drop ()///Remove Foo This collection, (S

MySQL allows you to quickly delete all tables without deleting databases. This example describes how MySQL can quickly delete all tables without deleting databases. We will share this with you for your reference. The details are as follows: If you use phpmyadmin directly, it must be very simple. Check "data table", cli

Original address: http://www.linuxbrigade.com/back-up-all-of-your-mysql-databases-nightly/Put the following into something like/usr/local/bin/mysql_backup.sh and since it have MySQL ' s root password in it, make Su Re that you chmod for it so no one else can read it.#!/bin/Bashdb_backup="/backups/mysql_backup/' Date +%y-%m-%d '"Db_user="Root"db_passwd="SECRETTTT"HN=`hostname|awk-F.'{print $}'' # Create the

Delete key in bulk There is a command DEL that removes a single key in Redis, but it seems there is no instruction to delete the key in bulk, but we can do this with the Linux xargs command. 1 2 3 Redis-cli-h ip-p Port Keys "*" | Xargs redis-cli-h ip-p Port del//If the REDIS-CLI is not set as a system variable, you need to specify the full path of the REDIS-CLI//such as:/opt/redis/redis-cli Keys "*" | Xargs/opt/redis/redis-cli del If you want to specify a Redis databas

memory mapping, which maps all data files into memory, but only virtual memory, which is only exchanged in material memory when the data is accessed. Each data file is divided into one block of data, and the block is connected to the block by a two-way chain. In the namespace file, the stored information metadata for each namespace is saved, including its size, number of blocks, the position of the first block, the position of the last piece,

MONGODB command queries all database lists CODE: > Show DBS If you want to see which database the current connection is under, you can enter the DB directly CODE: > DB Admin Want to switch to the test database below CODE: > Use test Switched to DB test > DB Test To see what tables or collection are under test, you can enter CODE: > Show Collections System.indexes User If you want to know which c

Tags: The conceptual relational database performs an insert email operation to get sudo dataNon-relational database command is case-sensitive; command Terminator is carriage return (unlike MySQL) MongoDB Configuration sudo service mongodb start mongo MongoDB Basic Concept 集合A concept that corresponds to a relational

In MongoDB, the Db.collection.remove () method is used to delete documents from the document. You can delete all documents from a collection, delete all documents that match one condition, or restrict actions to delete only one document. Delete all documents: To delete all

Label:Remove: Remove the wand with the from our name "Doom Bringer" wands collection. Db.wands.remove ({name: "Doom bringer"}) >> writeresult ({' ngremoved ': 1}) When we removed "Doom Bringer" the wand, we noticed that it had a power "Death" of, and we don ' t want any wands as that in our data Base. To is safe, let's remove any wands containing the in their powers . Db.wands.remove ({name: "Doom bringer

From Pymongo import mongoclientFrom Bson.objectid import ObjectidFrom Read_json Import ReadDef mongoclient ():Client = mongoclient (' 127.0.0.1 ', 27017)db = Client.testCollection = Db.test# Collection.insert ({})# for I in Collection.find ({"Name": "Leqing East Coast North Section"}):# Print (i)data = (' Coastlines.real.json ')Find_da = (' track ')find_id = (' Coastlineid ')Find_node = (' Nodes_index ')Want_data = Read (Data, Find_da) #传入json文件, query by keywordwant_id = Read (data, find_id)Wan

From Pymongo import mongoclientFrom Bson.objectid import ObjectidFrom Read_json Import ReadDef mongoclient ():Client = mongoclient (' 127.0.0.1 ', 27017)db = Client.testCollection = Db.test# Collection.insert ({})# for I in Collection.find ({"Name": "Leqing East Coast North Section"}):# Print (i)data = (' Coastlines.real.json ')Find_da = (' track ')find_id = (' Coastlineid ')Find_node = (' Nodes_index ')Want_data = Read (Data, Find_da) #传入json文件, query by keywordwant_id = Read (data, find_id)Wan