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One, DB data operation (1) Help view command prompt help db.help (); Db.yourColl.help (); Db.youColl.find (). Help (); Rs.help (); (2) switch/CREATE database use Yourdb; When a collection (table) is

Database Common Commands1. Help View command PromptHelpDb.help ();Db.yourColl.help ();Db.youColl.find (). Help ();Rs.help ();2. Switch/CREATE DatabaseUse Yourdb; The current database is created automatically when a collection (table) is created3.

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, but MongoDB does not have a command to create a database, but there

1.findDb.bind_info.find ({"Bd_type": 1})2.countDb.bind_info.find ({"Bd_type": 1}). Count ();3. Return to Fixed fieldDb.users.find ({},{"name": 1, "Age": 1})For example, if you want to create a "myTest" database, run the use myTest command first,

Transferred from: http://www.cnblogs.com/4mylife/archive/2012/10/25/2738466.htmlThe following table lists the differences between SET and SELECT SELECT SET When multiple variables are simultaneously assigned

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

Implementation statement for Oracle Update Data Update Sql>--Create demo table Sql> CREATE TABLE Employee ( 2 ID VARCHAR2 (4 BYTE) not NULL, 3 first_name VARCHAR2 (BYTE), 4 last_name VARCHAR2 (BYTE), 5 start_date Date, 6 end_date Date, 7

Continue the study of the previous article, "Flexible mastery of the asp.net in the GridView control of a variety of ways to use (above)", on this basis to consolidate the control of the GridView operation, a higher level. 11.GridView

Background:vlan123: User Service Vlan,192.168.1.0/24VLAN2001: Management vlan,172.168.129.0/24Vlan1: Default VLAN, not recommended.Precautions:When you configure a service set, the WLAN-BSS interface cannot be reused or missing.The VLAN

Implementation statement for Oracle Update Data Update Sql>--Create demo tableSql> CREATE TABLE Employee (2 ID VARCHAR2 (4 BYTE) not NULL,3 first_name VARCHAR2 (BYTE),4 last_name VARCHAR2 (BYTE),5 start_date Date,6 end_date Date,7 Salary Number (8,2

DB Shell Data operationShell command manipulation syntax is similar to JavaScript, in fact, the bottom of the console query statements are done with JavaScript script.#数据库 operation1. Help View command Prompt> help> db.help ();> db.yourColl.help ();>

First, the database commonly used commands1. Help View command PromptThe code is as follows: HelpDb.help ();Db.yourColl.help ();Db.youColl.find (). Help ();Rs.help ();2. Switch/CREATE DatabaseThe code is as follows: Use YOURDB; The current database

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

This article transferred from: http://www.cnblogs.com/liyonghui/p/mongodb.htmlAfter 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

Enter help to see the basic Operations Command:One: operation of the DB1. Creating a MongoDB database column such as creating a database named Pockbox use Pockbox, MongoDB does not have a command to create a database2, switch/CREATE database use

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 list Show Collections: Displays a collection

Reprinted from http://www.cnblogs.com/hoojo/archive/2011/06/01/2066426.html One, preparatory work1. Download MongoDB: Http://www.mongodb.org/downloadsChoose the right version for youRelated documents: Http://www.mongodb.org/display/DOCS/Tutorial2.

MongoDB Common Operations CommandsIf you want to create a "myTest" database, run the use myTest command first, then do something (such as: db.createcollection (' user ')) so you can create aBuild a database called "MyTest".First, the database

MongoDB Basic command withAfter 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

If there is no lock, concurrency is stronger, but data security can be problematic. So the database locks the data.Shared and exclusive locks也就是读写锁，共享锁可以叠加共享锁但是不能加排他锁， 排他锁则不能叠加。根据隔离级别等等，mysql会隐式的给数据自动加锁此外还可以使用share in model, for update