'Django 3.2+: implementing case-sensitive string comparisons within MySQL tables
Django documentation (3.2 to 4.0) states:
In MySQL, a database table’s collation determines whether string comparisons (such as the expression and substring of this function) are case-sensitive. Comparisons are case-insensitive by default.
from 3.2 on, there is mention that it is now possible to define at the level of the CharField the collation to use: https://docs.djangoproject.com/en/3.2/ref/databases/#collation-settings
but I find nowhere what value I should use for db_collation
to enable case-sensitive string comparisons for a given CharField:
case_sensitive_collation = ???
name = models.CharField(max_length=50, db_collation=case_sensitive_collation)
Just found this gist to do the contrary:
CreateCollation and db_collation to implement a case-insensitive Charfield with Postgres > 12
https://gist.github.com/hleroy/2f3c6b00f284180da10ed9d20bf9240a
can somebody help me out?
Edit:
here is the SHOW CREATE TABLE
. the goal would be to have the field pieces
case sensitive:
MariaDB [FormApp_db]> show create table puzzles_puzzlepieces;
+----------------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table |
+----------------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| puzzles_puzzlepieces | CREATE TABLE `puzzles_puzzlepieces` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`pieces` varchar(255) NOT NULL,
`uncolored_id` int(11) DEFAULT NULL,
`piece_setup_id` int(11) DEFAULT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `pieces` (`pieces`),
KEY `puzzles_puzzlepieces_uncolored_id_8afb6603_fk_puzzles_p` (`uncolored_id`),
CONSTRAINT `puzzles_puzzlepieces_uncolored_id_8afb6603_fk_puzzles_p` FOREIGN KEY (`uncolored_id`) REFERENCES `puzzles_puzzlepieces` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=3094388 DEFAULT CHARSET=utf8mb4 |
+----------------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.003 sec)
and the generated SELECT
:
>>> x = PuzzlePieces.objects.all()
>>> x[0]
SELECT `puzzles_puzzlepieces`.`id`,
`puzzles_puzzlepieces`.`pieces`,
`puzzles_puzzlepieces`.`uncolored_id`,
`puzzles_puzzlepieces`.`piece_setup_id`
FROM `puzzles_puzzlepieces`
LIMIT 1
Execution time: 0.002870s [Database: default]
Solution 1:[1]
To validate the solution proposed by @rickjames, I'll document an implementation of the answer here:
in settings.py:
if app_version == 'prod':
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.mysql',
'OPTIONS': {
'read_default_file': '/home/src/my.cnf'
}
}
}
DB_IS_MYSQL = True
else:
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.sqlite3',
'NAME': os.path.join(BASE_DIR, 'db.sqlite3'),
}
}
DB_IS_MYSQL = False
MYSQL_SENSITIVE_COLLATION = 'ascii_bin'
DB_CASE_SENSITIVE_COLLATION = {'db_collation': MYSQL_SENSITIVE_COLLATION} if DB_IS_MYSQL else {}
# Use:
# from django.conf import settings
# pieces = models.CharField(max_length=255, default='empty', unique=True, **settings.DB_CASE_SENSITIVE_COLLATION)
in model.py:
name = models.CharField(max_length=50, **settings.DB_CASE_SENSITIVE_COLLATION)
Sources
This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.
Source: Stack Overflow
Solution | Source |
---|---|
Solution 1 | Skratt |