#13666: Updates with F objects on decimal fields raise MySQL warnings
-------------------------------------+-------------------------------------
Reporter: KyleMac | Owner: nobody
Type: Bug | Status: closed
Component: Database layer | Version: 1.7
(models, ORM) | Resolution:
Severity: Normal | worksforme
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Changes (by Simon Charette):
* status: new => closed
* resolution: => worksforme
Comment:
I'm not able to reproduce anymore on MySQL 8 strict mode (minimum version
planned for 4.2) so they must have sorted out their decimal arithmetic
over the years so even if the `Cast` could be added by
`CombinedExpression` or even by MySQL's `combine_expression` I don't think
it's worth doing at this point.
Closing as ''worksforme'' as demonstrated by this test.
{{{#!diff
diff --git a/tests/model_fields/models.py b/tests/model_fields/models.py
index 9a64d51766..2a9bcd95cc 100644
--- a/tests/model_fields/models.py
+++ b/tests/model_fields/models.py
@@ -16,6 +16,10 @@
except ImportError:
Image = None
+class Account(models.Model):
+ name = models.CharField(max_length=100)
+ balance = models.DecimalField(decimal_places=2, max_digits=12)
+
class Foo(models.Model):
a = models.CharField(max_length=10)
diff --git a/tests/model_fields/test_decimalfield.py
b/tests/model_fields/test_decimalfield.py
index 912d55af72..a45e634ff4 100644
--- a/tests/model_fields/test_decimalfield.py
+++ b/tests/model_fields/test_decimalfield.py
@@ -3,10 +3,10 @@
from django.core import validators
from django.core.exceptions import ValidationError
-from django.db import models
+from django.db import models, connection
from django.test import TestCase
-from .models import BigD, Foo
+from .models import Account, BigD, Foo
class DecimalFieldTests(TestCase):
@@ -113,3 +113,14 @@ def test_roundtrip_with_trailing_zeros(self):
obj = Foo.objects.create(a="bar", d=Decimal("8.320"))
obj.refresh_from_db()
self.assertEqual(obj.d.compare_total(Decimal("8.320")),
Decimal("0"))
+
+ def test_update_difference(self):
+ acc = Account.objects.create(balance="10.00")
+ acc.balance = models.F("balance") - "1.79"
+ acc.save()
+ acc.refresh_from_db()
+ self.assertEqual(acc.balance, Decimal("8.21"))
+ with connection.cursor() as cursor:
+ cursor.execute("SHOW WARNINGS")
+ self.assertIsNone(cursor.fetchone())
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/13666#comment:14>
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