max length of primary key

2004-01-07 Thread Francis Mak 
Hi,

I have a problem when creating a table:


CREATE TABLE test (
test_key varchar(255) NOT NULL default '',
test_value text NOT NULL,
PRIMARY KEY (test_key) ) TYPE=MYISAM;

It then report error:

mySQL Error: Specified key was too long. Max key length is 500

Why the varchar exceeded 500?
I have a set-variable= default-character-set=utf8 in my.cnf,  maybe
this is the cause of error?
And is there way to increase this 500 value?  Or I must use InnoDB then?

Mysql 4.1.1, RedHat 9

Thanks.

Francis Mak

Re: max length of primary key

2004-01-07 Thread Martijn Tonies 
Hi,

 I have a problem when creating a table:


 CREATE TABLE test (
 test_key varchar(255) NOT NULL default '',
 test_value text NOT NULL,
 PRIMARY KEY (test_key) ) TYPE=MYISAM;

 It then report error:

 mySQL Error: Specified key was too long. Max key length is 500

 Why the varchar exceeded 500?
 I have a set-variable= default-character-set=utf8 in my.cnf,  maybe
 this is the cause of error?
 And is there way to increase this 500 value?  Or I must use InnoDB then?

Apparently, the 500 number is bytes. Assuming UTF8 takes
at least two bytes/character, then yes, your VARCHAR(255)
takes up more than 500 bytes.

With regards,

Martijn Tonies
Database Workbench - developer tool for InterBase, Firebird, MySQL  MS SQL
Server.
Upscene Productions
http://www.upscene.com


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