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Fixed #25517 -- Made Concat function idempotent on SQLite.

This commit is contained in:
Josh Smeaton 2015-10-14 10:07:42 +11:00 committed by Tim Graham
parent 0922bbf18d
commit 6c95b134e9
3 changed files with 26 additions and 7 deletions

View File

@ -42,10 +42,10 @@ class ConcatPair(Func):
super(ConcatPair, self).__init__(left, right, **extra)
def as_sqlite(self, compiler, connection):
self.arg_joiner = ' || '
self.template = '%(expressions)s'
self.coalesce()
return super(ConcatPair, self).as_sql(compiler, connection)
coalesced = self.coalesce()
coalesced.arg_joiner = ' || '
coalesced.template = '%(expressions)s'
return super(ConcatPair, coalesced).as_sql(compiler, connection)
def as_mysql(self, compiler, connection):
# Use CONCAT_WS with an empty separator so that NULLs are ignored.
@ -55,9 +55,12 @@ class ConcatPair(Func):
def coalesce(self):
# null on either side results in null for expression, wrap with coalesce
c = self.copy()
expressions = [
Coalesce(expression, Value('')) for expression in self.get_source_expressions()]
self.set_source_expressions(expressions)
Coalesce(expression, Value('')) for expression in c.get_source_expressions()
]
c.set_source_expressions(expressions)
return c
class Concat(Func):

View File

@ -23,3 +23,5 @@ Bugfixes
have their reverse relations disabled (:ticket:`25545`).
* Allowed filtering over a ``RawSQL`` annotation (:ticket:`25506`).
* Made the ``Concat`` database function idempotent on SQLite (:ticket:`25517`).

View File

@ -7,7 +7,8 @@ from django.db import connection
from django.db.models import CharField, TextField, Value as V
from django.db.models.expressions import RawSQL
from django.db.models.functions import (
Coalesce, Concat, Greatest, Least, Length, Lower, Now, Substr, Upper,
Coalesce, Concat, ConcatPair, Greatest, Least, Length, Lower, Now, Substr,
Upper,
)
from django.test import TestCase, skipIfDBFeature, skipUnlessDBFeature
from django.utils import six, timezone
@ -353,6 +354,19 @@ class FunctionTests(TestCase):
expected = article.title + ' - ' + article.text
self.assertEqual(expected.upper(), article.title_text)
@skipUnless(connection.vendor == 'sqlite', "sqlite specific implementation detail.")
def test_concat_coalesce_idempotent(self):
pair = ConcatPair(V('a'), V('b'))
# Check nodes counts
self.assertEqual(len(list(pair.flatten())), 3)
self.assertEqual(len(list(pair.coalesce().flatten())), 7) # + 2 Coalesce + 2 Value()
self.assertEqual(len(list(pair.flatten())), 3)
def test_concat_sql_generation_idempotency(self):
qs = Article.objects.annotate(description=Concat('title', V(': '), 'summary'))
# Multiple compilations should not alter the generated query.
self.assertEqual(str(qs.query), str(qs.all().query))
def test_lower(self):
Author.objects.create(name='John Smith', alias='smithj')
Author.objects.create(name='Rhonda')