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Creating a field with a Key of MUL

 When you use the Desc table command, there is a column termed 'KEY" in which each field can be nothing, PRI, or MUL.  When I create a table what is the syntax to make a field have a Key of MUL ?
0
parkhill04
Asked:
parkhill04
1 Solution
 
arantiusCommented:
parkhill04,
Referencing http://216.239.39.104/search?q=cache:jEP-ueFGYdcJ:www.bitmechanic.com/mail-archives/mysql/current/0568.html+mysql+key+mul&hl=en&client=firefox-a   (page is dead, google cache is available):

"MUL means that the key allows multiple rows to have the same value.  That is, it's not a UNIque key. "
0
 
PetrTomenendalCommented:
you can create "MUL" key this way:
create table example (
 nonunique int(9),
 key(nonunique)
);

usual use is when you have 1:N or N:N relation between tables, for example:
create table colors (
 id_color int(5) unsigned not null auto_increment,
 name varchar(50),
 primary key(id_color)
);

create table cars (
 id_car int(9) unsigned not nul auto_increment,
 carname varchar(100),
 id_color int(5) unsigned not null,
 primary key(id_car),
 key(id_color)
);

relation between colors and cars is 1:N - so id_color is multiple key in cars table
0

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