key add

Use dB; -- List all tables in the current database Show tables; Show tables like's % '; Create Table Name ( Column name type modification constraints, Sid int (3) unsigned zerofill primary key auto_increment Sgender Enum ('male', 'female ',

There's a thing that's been bothering me in my head, but it's not clear that it's going to hinder my progress. Do your own project demo can always use only one sheet ... So today is still learning the next foreign key hope to understand some

In the process of MySQL creating a table foreign key, due to improper operation, will prompt cannot add foreign KEY constraint error.This error may be caused by the following reasons:1. The data type does not match, and the key associated with the

--Delete primary keyALTER TABLE name drop constraint primary Key name--Add primary keyALTER TABLE name add constraint primary Key name primary key (field name 1, field Name 2 ...)--Add a primary key for a nonclustered indexALTER TABLE name add

--Delete primary keyALTER TABLE name drop constraint primary Key name--Add primary keyALTER TABLE name add constraint primary Key name primary key (field name 1, field Name 2 ...)--Add a primary key for a nonclustered indexALTER TABLE name add

--Delete primary Key Alter TableTable nameDrop constraintPRIMARY Key Name--Add primary Key Alter TableTable nameAdd constraintPrimary Key NamePrimary Key(field name 1, field Name 2 ...)--to add a primary key for a nonclustered index Alter TableTable

GO--determine if the table exists in the way 1if object_id(N'Ef_user'N'U') is NULL--determine if the table exists in the way 2--If not EXISTS (SELECT * FROM dbo. SysObjects WHERE id = object_id (N ' [Ef_user] ') and OBJECTPROPERTY (ID, ' istable ') =

The construction of POF environment one. General overviewThe architecture PC1 is the controller, and the PC2 is the switch. PC3 is a server/client (a PC with two virtual machines, you need to set the network connection mode to bridge.) According to

Alarm problem:Too many processes onZabbix Poller processes more than 75% busyZabbix unreachable Poller processes more than 75% busy1. The device that collects the data through the Zabbix agent is in the moniting state but at this time the machine

The famous VirtualBox is an open-source and free virtual machine software and a cross-platform software. It is one of the famous products of SUN, and now belongs to Oracle, the software still adheres to the previous principle of shengyang, and the

RSS Guard is a lightweight RSS reader written in C ++ and Qt. Through an intuitive graphical user interface and built-in news messages, users can also subscribe to information from other websites that provide Feed, and use a dedicated icon tool to

The famous VirtualBox is an open-source and free virtual machine software and a cross-platform software. It is one of the famous products of SUN, and now belongs to Oracle, the software still adheres to the previous principle of shengyang, and the

During the business stress testing of a project, the following problems were encountered:The Zabbix monitor message displays the following error:2016.09.28 19:16:11Trigger:mysql error log desc in lines_2Values:mysql error_log:2016-09-28 19:16:10 4723

sudo sh -c ‘echo "deb http://download.virtualbox.org/virtualbox/debian xenial contrib" >> /etc/apt/sources.list.d/virtualbox.list‘wget -q https://www.virtualbox.org/download/oracle_vbox_2016.asc -O- | sudo apt-key add -sudo apt updatesudo apt

RSSGuard is a lightweight RSS reader written in C ++ and Qt. With an intuitive graphical user interface, you can use this software to subscribe to the information of the built-in RSS website, import and export the feed from other customers, and

1. Edit the/etc/apt/sources. list file and add any of the following sources: debhttp: // sources 1. Edit the/etc/apt/sources. list file and add any of the following sources. Deb http://www.beerorkid.com/compiz edgy main-edgy Deb

Step 1: Add a new source Sudo VI/etc/APT/sources. List Add at the end of the file:Http://ubuntu.compiz.net/edgy main-edgyYou can also add one of the following sources:Deb http://www.beerorkid.com/compiz edgy

N statement: This post is not original to me. It is a forum. It is collected and summarized in the wiki. I just hope to give it to all of you. If there are any errors, please correct me!Section 1 BackgroundUbuntu6.10 edgy has been released for two

This article describes how to use the defaultdict module in the Python standard library. This article describes how to use defaultdict to add the default type to the value element of the dictionary and two use cases of defaultdict, you can refer to

In Ubuntu7.10, 3D desktops enjoy the latest nvidia graphics card drivers that have directly supported the 3D effects under Ubuntu7.10. xorg7.1 has replaced the previous xgl functions and can directly support compiz. therefore, it is very easy to