#31144: MySQL unique constraints incorrectly limited to 255 char when it should
be
1000
-------------------------------------+-------------------------------------
Reporter: Steven | Owner: nobody
Mapes |
Type: Bug | Status: new
Component: Database | Version: 3.0
layer (models, ORM) | Keywords: MySQL, MAriaDB,
Severity: Normal | Unique
Triage Stage: | Has patch: 0
Unreviewed |
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 0
UI/UX: 0 |
-------------------------------------+-------------------------------------
There is a bug within db.backends.mysql.validation.check_field_type where
the maximum unique constraints is still being limited to 255 characters
even though MySQL supports unique keys of up to 1000 characters by default
and InnoDB supports 3072 bytes for InnoDB tables that use DYNAMIC or
COMPRESSED row format and 767 bytes for InnoDB tables that use the
REDUNDANT or COMPACT row format.
Reference -
InnoDB - https://dev.mysql.com/doc/refman/8.0/en/innodb-limits.html
MyISAM - https://dev.mysql.com/doc/refman/8.0/en/myisam-storage-
engine.html
Example
CREATE DATABASE `test`CHARACTER SET utf8 COLLATE utf8_general_ci;
USE test;
{{{
CREATE TABLE `example_innodb` (
`example1` VARCHAR(1024) DEFAULT NULL,
`example2` VARCHAR(1024) DEFAULT NULL,
UNIQUE KEY `UQ_example1` (`example1`),
UNIQUE KEY `UQ_example2` (`example2`)
) ENGINE=INNODB DEFAULT CHARSET=utf8
DROP TABLE example_innodb;
DROP DATABASE test;
}}}
It just needs the max length to be increased on line 38 of
db.backends.mysql.validation
--
Ticket URL: <https://code.djangoproject.com/ticket/31144>
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