MongoDB

Db.copydatabase ("from", "to", "127.0.0.1:16161");The From library on the 127.0.0.1. Copy to the to library.There is an added benefit to doing so. This is the library in the From library that may have deleted the data. Look, we know that disk space

1. Course OutlineThis course introduces the knowledge of MONGODB data model, including the basic concepts of documents, collections and databases, usage methods and naming rules, the introduction of MONGODB basic data types and the introduction and

Recently wrote a crawler tool, the data stored in the Web site MongoDB, because the data are duplicated, so I set up the database when the index, the following is my step, the set name is Drugitem,Here is the collection:I want to create a unique

1. Table-related commands:Db. AddUser (username,password) Add user Db.auth (Usrename,password) Set database connection validation db.clonedatabase (fromhost) clone a database from the target server db.com MANDHELP (name) returns the

Access database: MONGO View all Databases:> show DBS > show Dbsadmin (empty) local 0. 031GBnutch 0. 031GBtest (empty) Create/Switch database:> use Nutch View Database:> Db.stats () View database Tables:>

1. DownloadPre-compiled PHP MongoDB driver binaries (: Php_mongo) for the Windows platform have been provided on GitHub and can be downloaded in a version corresponding to PHP in the real world. I built the environment in PHP version 5.6.11, so the

Connecting a database with a Pymongo package Use the XLRD package to read Excel data, and to convert Excel format data to JSON-formatted data due to different data structures "TypeError: ' str ' object does not a support item assignment" due to a

sharding refers to data fragmentationcluster cluster, a cluster contains multiple shards, each shard consists of a replica setCollection The concept of a table in db, except that there is no schemaEach collection in the sharding scene is divided

As the company's business development MSSQL has been in the bottleneck. Because there is no money to buy a big server can only rely on software to achieve maximum optimization. The original system architecture is as follows:Now you're ready to

Inert into users value (3,5) Db.users.insert ({a:3,b:5}) Select a, b from users Db.users.find ({}, {a:1,b:1}) SELECT * from Users Db.users.find () SELECT * from Users

installing MongoDB on Ubuntu Kylin15.05MongoDB is a typical nosql, but it is said to be used by many people. So I tried to install this database on Ubuntu Kylin.First go to its official website to see it. Link address: https://www.mongodb.org, the

As with databases, group is often used for statistics. MongoDB Group also has a lot of restrictions, such as: The return result set can not exceed 16M, the group operation will not process more than 10,000 unique keys. It seems that the index cannot

After the successful start of MongoDB, and then open a command line window input MONGO, you can do some of the database operations.Enter help to see the basic Operations Command:Show DBS: Display Database listShow Collections: Displays a collection

PHP extension mongon.mod.dll Download http://cn.php.net/manual/en/mongo.installation.php#mongo.installation.windowsThen php.ini add Extension=php_mongo.dllFinally Phpinfo () foundTable tag PHP has its own MONGO feature, you can manipulate the

What's a namespace in MongoDB? If you remove a document, does MongoDB remove it from disk? When is does MongoDB write updates to disk? How does I do transactions and locking in MongoDB? How does aggregate data with MongoDB? Why does

Overview replica set is a master-slave replication, is a self-failover function of the master-slave replication, to solve the shortcomings of the master-slave replication, the realization of the main server failure, no human intervention, the system

OverviewThe above two blog is about the configuration of MongoDB cluster, not related to distributed, the blog is to write MongoDB distributed, a whole, divided into multiple slices, each piece deployed to a different server, this is MongoDB

Create a C3P0 Data Source When creating a C3P0 data source, there are very few connections to the database using JDBC in actual development. Generally, the data source is used. C3P0 is an open source data source, and the actual project is used a lot:

Normal database disabling hang To avoid problems caused by abnormal shutdown, we have a test database that uses shutdown normal to stop the database. The result is that the hang is very common.   Operation Sequence:? 1. shutdown normal, and then

[Sorting] Summary of common MongoDB commands Summary of common MongoDB commands   Simple addition, deletion, modification, and query dataSpecify whether to display or not to display a field in the query result. For example, we want to search