I have a similar problem indexing a TEXT field. I am trying to create a
unique index on the first 1024 characters of a TEXT field:
* >mysql
* Welcome to the MySQL monitor. Commands end with ; or \g.
* Your MySQL connection id is 66 to server version: 3.23.32
*
* CREATE TABLE abc (
* f1 TEXT NOT NULL,
* f2 VARCHAR(20) NOT NULL,
* f3 VARCHAR(20) NOT NULL,
* f4 VARCHAR(20) NOT NULL,
* f5 TEXT NOT NULL,
*
* # 255 works ok, 256 does not work.
* INDEX (f1(256))
* );
*
* ERROR 1089 at line 3: Incorrect sub part key. The used key
part isn't a
* string or the used length is longer than the key part
According to the documentation, TEXT fields hold up to 2^16 characters, and
I can find no documented limitation on index size.
As it stands at present, I can only index the first 255 character, and
manually check for a duplicate record before inserting a new record.
David Robinson.
-----------------------------------
From: Mike Thompson
Date: Wed, 07 Mar 2001 07:49:22 -0600
Yes, I've tries that here is the error I get.
Your MySQL connection id is 247 to server version: 3.23.33
mysql> CREATE TABLE foo(
-> id INT NOT NULL AUTO_INCREMENT,
-> name BLOB NOT NULL,
-> PRIMARY KEY(id),
-> UNIQUE(name(500))
-> );
ERROR 1089: Incorrect sub part key. The used key part isn't a string or
the used length is longer than the key part
Pat Sherrill wrote:
>
> BLOBS and TEXT columns used as indices require the length to be
specifically
> enumerated.
> (Sec 7.26 of the manual)
>
> CREATE TABLE foo(
> id INT NOT NULL AUTO_INCREMENT,
> name BLOB NOT NULL,
> PRIMARY KEY(id),
> UNIQUE(name(500))
> );
>
> Pat...
> [EMAIL PROTECTED]
>
> ----- Original Message -----
> From: "Mike Thompson" <[EMAIL PROTECTED]>
> To: "mysql" <[EMAIL PROTECTED]>
> Sent: Tuesday, March 06, 2001 1:51 PM
> Subject: key lengths
>
> > How is key length for a table defined? It seems that the default is 255
> > bytes, but in the online docs it mentions 500 byte keys. I happen to
> > have some very long case sensitive strings that I need to use as keys,
> > but mysql complains when I try to create a table as such
> >
> > CREATE TABLE foo(
> > id INT NOT NULL AUTO_INCREMENT,
> > name BLOB NOT NULL,
> > PRIMARY KEY(id),
> > UNIQUE(name)
> > );
> >
> > Any thoughts?
> > --m
> >
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--
>--------------------------------------------------------<
Michael R. Thompson Instanton Corporation
Sr. Software Developer 1250 Capital of Texas Highway South
[EMAIL PROTECTED] Building 3 suite 200
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