Commit eb6c1076 authored by Nick Sandford's avatar Nick Sandford Committed by Claude Paroz
Browse files

Fixed #19360 -- Raised an explicit exception for aggregates on date/time fields in sqlite3 

Thanks lsaffre for the report and Chris Medrela for the initial
patch.
parent 2e55cf58

django/db/backends/sqlite3/base.py

+13 −0
Original line number Diff line number Diff line
@@ -18,6 +18,8 @@ from django.db.backends.signals import connection_created 
from django.db.backends.sqlite3.client import DatabaseClient

from django.db.backends.sqlite3.creation import DatabaseCreation

from django.db.backends.sqlite3.introspection import DatabaseIntrospection

from django.db.models import fields

from django.db.models.sql import aggregates

from django.utils.dateparse import parse_date, parse_datetime, parse_time

from django.utils.functional import cached_property

from django.utils.safestring import SafeBytes
@@ -127,6 +129,17 @@ class DatabaseOperations(BaseDatabaseOperations): 
        limit = 999 if len(fields) > 1 else 500

        return (limit // len(fields)) if len(fields) > 0 else len(objs)



    def check_aggregate_support(self, aggregate):

        bad_fields = (fields.DateField, fields.DateTimeField, fields.TimeField)

        bad_aggregates = (aggregates.Sum, aggregates.Avg,

                          aggregates.Variance, aggregates.StdDev)

        if (isinstance(aggregate.source, bad_fields) and

                isinstance(aggregate, bad_aggregates)):

            raise NotImplementedError(

                'You cannot use Sum, Avg, StdDev and Variance aggregations '

                'on date/time fields in sqlite3 '

                'since date/time is saved as text.')



    def date_extract_sql(self, lookup_type, field_name):

        # sqlite doesn't support extract, so we fake it with the user-defined

        # function django_extract that's registered in connect(). Note that

docs/ref/models/querysets.txt

+8 −0
Original line number Diff line number Diff line
@@ -2188,6 +2188,14 @@ Django provides the following aggregation functions in the 
aggregate functions, see

:doc:`the topic guide on aggregation </topics/db/aggregation>`.



.. warning::



    SQLite can't handle aggregation on date/time fields out of the box.

    This is because there are no native date/time fields in SQLite and Django

    currently emulates these features using a text field. Attempts to use

    aggregation on date/time fields in SQLite will raise

    ``NotImplementedError``.



Avg

~~~

tests/regressiontests/backends/models.py

+11 −0
Original line number Diff line number Diff line
@@ -75,3 +75,14 @@ class Article(models.Model): 


    def __str__(self):

        return self.headline





@python_2_unicode_compatible

class Item(models.Model):

    name = models.CharField(max_length=30)

    date = models.DateField()

    time = models.TimeField()

    last_modified = models.DateTimeField()



    def __str__(self):

        return self.name

tests/regressiontests/backends/tests.py

+17 −1
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ from django.db import (backend, connection, connections, DEFAULT_DB_ALIAS, 
    IntegrityError, transaction)

from django.db.backends.signals import connection_created

from django.db.backends.postgresql_psycopg2 import version as pg_version

from django.db.models import fields, Sum, Avg, Variance, StdDev

from django.db.utils import ConnectionHandler, DatabaseError, load_backend

from django.test import (TestCase, skipUnlessDBFeature, skipIfDBFeature,

    TransactionTestCase)
@@ -362,6 +363,22 @@ class EscapingChecks(TestCase): 
        self.assertTrue(int(response))





class SqlliteAggregationTests(TestCase):

    """

    #19360: Raise NotImplementedError when aggregating on date/time fields.

    """

    @unittest.skipUnless(connection.vendor == 'sqlite',

                         "No need to check SQLite aggregation semantics")

    def test_aggregation(self):

        for aggregate in (Sum, Avg, Variance, StdDev):

            self.assertRaises(NotImplementedError,

                models.Item.objects.all().aggregate, aggregate('time'))

            self.assertRaises(NotImplementedError,

                models.Item.objects.all().aggregate, aggregate('date'))

            self.assertRaises(NotImplementedError,

                models.Item.objects.all().aggregate, aggregate('last_modified'))





class BackendTestCase(TestCase):



    def create_squares_with_executemany(self, args):
@@ -400,7 +417,6 @@ class BackendTestCase(TestCase): 
            self.create_squares_with_executemany(args)

        self.assertEqual(models.Square.objects.count(), 9)





    def test_unicode_fetches(self):

        #6254: fetchone, fetchmany, fetchall return strings as unicode objects

        qn = connection.ops.quote_name