How do I specify unique constraint for multiple columns in MySQL?

Posted by Niyaz on Stack Overflow See other posts from Stack Overflow or by Niyaz
Published on 2009-03-11T19:12:31Z Indexed on 2010/05/07 21:28 UTC
Read the original article Hit count: 262

Filed under:

mysql

|

constraints

|

table

|

database

|

query

I have a table:

table votes (
    id,
    user,
    email,
    address,
    primary key(id),
);

Now I want to make the columns user, email, address unique (together).

How do I do this in MySql?

Thanks in advance.

Of course the example is just... an example. So please don't worry about the semantics.

© Stack Overflow or respective owner

Related posts about mysql

How to remove MySQL completely with config and library files on ubuntu 12.04 gnome 3.0

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I tried everything till now: sudo apt-get remove mysql-server mysql-client mysql-common sudo apt-get purge mysql-server mysql-client mysql-common sudo apt-get autoremove and even more commands... But whenever I am trying to locate mysql. I get a no. of files related to mysql command: shell>>… >>> More
mysql: Cannot load from mysql.proc. The table is probably corrupted

as seen on Server Fault - Search for 'Server Fault'
Mysql was started: /usr/bin/mysqld_safe --datadir=/srv/mysql/myDB --log-error=/srv/mysql/logs/mysqld-myDB.log --pid-file=/srv/mysql/pids/mysqld-myDB.pid --user=mysql --socket=/srv/mysql/sockets/mysql-myDB.sock --port=3700 but when I'm trying to do something: ERROR 1548 (HY000) at line 1: Cannot… >>> More
Why is there a /etc/init.d/mysql file on this Slackware machine? How could it have gotten there?

as seen on Server Fault - Search for 'Server Fault'
A client of my IT-consulting service owns a web-development shop. He's been having problems with a Slackware 12.0 server running MySQL 5.0.67. The machine was set up by the client's sysadmin, who left on bad terms. My client no longer employs a sysadmin. As far as I can tell, the only copy of MySQL… >>> More
mysql: Bind on unix socket: Permission denied

as seen on Server Fault - Search for 'Server Fault'
Can't start mysql with: sudo /usr/bin/mysqld_safe --datadir=/srv/mysql/myDB --log-error=/srv/mysql/logs/mysqld-myDB.log --pid-file=/srv/mysql/pids/mysqld-myDB.pid --user=mysql --socket=/srv/mysql/sockets/mysql-myDB.sock --port=3700 120222 13:40:48 mysqld_safe Starting mysqld daemon with databases… >>> More
MySQL – Learning MySQL Online in 6 Hours – MySQL Fundamentals in 320 Minutes

as seen on SQL Authority - Search for 'SQL Authority'
MySQL is one of the most popular database language and I have been recently working with it a lot. Data have no barrier and every database have their own place. I have been working with MySQL for quite a while and just like SQL Server, I often find lots of people asking me if I have a tutorial which… >>> More

Related posts about constraints

Java JTextPane JScrollPane Display Issue

as seen on Stack Overflow - Search for 'Stack Overflow'
The following class implements a chatGUI. When it runs okay the screen looks like this: Fine ChatGUI The problem is very often when i enter text of large length ie. 50 - 100 chars the gui goes crazy. the chat history box shrinks as shown in this image. Any ideas regarding what is causing this? Thank… >>> More
AWT Textfield behaves weird with MicroSoft JVM

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi, I am facing a weird problem when using MicroSoft JVM to run my Applet. I have an AWT panel with 4 textfields which is added to a dialog box. Everything goes fine until I enter a decimal value into the textfield and close the dialog box. When i reopen the dialog box the textfield inside the panel… >>> More
MS SQL Bridge Table Constraints

as seen on Stack Overflow - Search for 'Stack Overflow'
Greetings - I have a table of Articles and a table of Categories. An Article can be used in many Categories, so I have created a table of ArticleCategories like this: BridgeID int (PK) ArticleID int CategoryID int Now, I want to create constraints/relationships such that the ArticleID-CategoryID… >>> More
jquery slider control issue

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi All, I am using slider control to create a progress bar for media player. Problem: the max value and slider size is not matching. The video get complete before it reaches the end of the slider. Code: <script type="text/javascript" src="js/jquery.ui.core.js"></script> <script… >>> More
Ask Tom: "On Constraints, Metadata, and Truth"

as seen on Oracle Technology Network - Search for 'Oracle Technology Network'
Our technologist uses constraints to improve query performance. >>> More