At 3:35 +0800 6/14/02, Andy Sy wrote: >----- Original Message ----- >From: "Paul DuBois" <[EMAIL PROTECTED]> >To: "Andy Sy" <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]> >Sent: Friday, June 14, 2002 2:45 AM >Subject: Re: Why does Key==Mul in DESCRIBE TABLE for unique key? > > >> At 2:03 +0800 6/14/02, Andy Sy wrote: >> >mysql> CREATE TABLE X (FLD1 INT UNIQUE); >> >Query OK, 0 rows affected (0.05 sec) >> > >> >mysql> DESCRIBE X; >> >+-------+---------+------+-----+---------+-------+ >> >| Field | Type | Null | Key | Default | Extra | >> >+-------+---------+------+-----+---------+-------+ >> >| FLD1 | int(11) | YES | MUL | NULL | | >> >+-------+---------+------+-----+---------+-------+ >> > >> >Doesn't MUL mean a key can exist multiple times >> >in the index? >> >> Right. It means it's part of a non-unique index. > >But I declared the field as UNIQUE (see the CREATE >TABLE statement).
UNIQUE indexes can contain multiple NULL values. Declare the column as FLD1 INT NOT NULL UNIQUE and you'll see a difference. --------------------------------------------------------------------- Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail <[EMAIL PROTECTED]> To unsubscribe, e-mail <[EMAIL PROTECTED]> Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
