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Code Issues 25 Releases Wiki Activity

Fixed #10154: Allow combining F expressions with timedelta values.

Browse Source 
git-svn-id: http://code.djangoproject.com/svn/django/trunk@15018 bcc190cf-cafb-0310-a4f2-bffc1f526a37
This commit is contained in:
Karen Tracey 2010-12-22 03:34:04 +00:00
parent f0cd656ee0
commit b1f6a4d66f
11 changed files with 360 additions and 4 deletions
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9
django/db/backends/__init__.py
View File

@ -154,6 +154,9 @@ class BaseDatabaseFeatures(object):
# deferred
can_defer_constraint_checks = False
# date_interval_sql can properly handle mixed Date/DateTime fields and timedeltas
supports_mixed_date_datetime_comparisons = True
# Features that need to be confirmed at runtime
# Cache whether the confirmation has been performed.
_confirmed = False
@ -220,6 +223,12 @@ class BaseDatabaseOperations(object):
"""
raise NotImplementedError()
def date_interval_sql(self, sql, connector, timedelta):
"""
Implements the date interval functionality for expressions
"""
raise NotImplementedError()
def date_trunc_sql(self, lookup_type, field_name):
"""
Given a lookup_type of 'year', 'month' or 'day', returns the SQL that

4
django/db/backends/mysql/base.py
View File

@ -158,6 +158,10 @@ class DatabaseOperations(BaseDatabaseOperations):
sql = "CAST(DATE_FORMAT(%s, '%s') AS DATETIME)" % (field_name, format_str)
return sql
def date_interval_sql(self, sql, connector, timedelta):
return "(%s %s INTERVAL '%d 0:0:%d:%d' DAY_MICROSECOND)" % (sql, connector,
timedelta.days, timedelta.seconds, timedelta.microseconds)
def drop_foreignkey_sql(self):
return "DROP FOREIGN KEY"

14
django/db/backends/oracle/base.py
View File

@ -118,6 +118,20 @@ WHEN (new.%(col_name)s IS NULL)
else:
return "EXTRACT(%s FROM %s)" % (lookup_type, field_name)
def date_interval_sql(self, sql, connector, timedelta):
"""
Implements the interval functionality for expressions
format for Oracle:
(datefield + INTERVAL '3 00:03:20.000000' DAY(1) TO SECOND(6))
"""
minutes, seconds = divmod(timedelta.seconds, 60)
hours, minutes = divmod(minutes, 60)
days = str(timedelta.days)
day_precision = len(days)
fmt = "(%s %s INTERVAL '%s %02d:%02d:%02d.%06d' DAY(%d) TO SECOND(6))"
return fmt % (sql, connector, days, hours, minutes, seconds,
timedelta.microseconds, day_precision)
def date_trunc_sql(self, lookup_type, field_name):
# Oracle uses TRUNC() for both dates and numbers.
# http://download-east.oracle.com/docs/cd/B10501_01/server.920/a96540/functions155a.htm#SQLRF06151

17
django/db/backends/postgresql/operations.py
View File

@ -27,6 +27,23 @@ class DatabaseOperations(BaseDatabaseOperations):
else:
return "EXTRACT('%s' FROM %s)" % (lookup_type, field_name)
def date_interval_sql(self, sql, connector, timedelta):
"""
implements the interval functionality for expressions
format for Postgres:
(datefield + interval '3 days 200 seconds 5 microseconds')
"""
modifiers = []
if timedelta.days:
modifiers.append(u'%s days' % timedelta.days)
if timedelta.seconds:
modifiers.append(u'%s seconds' % timedelta.seconds)
if timedelta.microseconds:
modifiers.append(u'%s microseconds' % timedelta.microseconds)
mods = u' '.join(modifiers)
conn = u' %s ' % connector
return u'(%s)' % conn.join([sql, u'interval \'%s\'' % mods])
def date_trunc_sql(self, lookup_type, field_name):
# http://www.postgresql.org/docs/8.0/static/functions-datetime.html#FUNCTIONS-DATETIME-TRUNC
return "DATE_TRUNC('%s', %s)" % (lookup_type, field_name)

32
django/db/backends/sqlite3/base.py
View File

@ -9,6 +9,7 @@ standard library.
import re
import sys
import datetime
from django.db import utils
from django.db.backends import *
@ -63,6 +64,7 @@ class DatabaseFeatures(BaseDatabaseFeatures):
test_db_allows_multiple_connections = False
supports_unspecified_pk = True
supports_1000_query_parameters = False
supports_mixed_date_datetime_comparisons = False
def _supports_stddev(self):
"""Confirm support for STDDEV and related stats functions
@ -90,6 +92,16 @@ class DatabaseOperations(BaseDatabaseOperations):
# cause a collision with a field name).
return "django_extract('%s', %s)" % (lookup_type.lower(), field_name)
def date_interval_sql(self, sql, connector, timedelta):
# It would be more straightforward if we could use the sqlite strftime
# function, but it does not allow for keeping six digits of fractional
# second information, nor does it allow for formatting date and datetime
# values differently. So instead we register our own function that
# formats the datetime combined with the delta in a manner suitable
# for comparisons.
return u'django_format_dtdelta(%s, "%s", "%d", "%d", "%d")' % (sql,
connector, timedelta.days, timedelta.seconds, timedelta.microseconds)
def date_trunc_sql(self, lookup_type, field_name):
# sqlite doesn't support DATE_TRUNC, so we fake it with a user-defined
# function django_date_trunc that's registered in connect(). Note that
@ -197,6 +209,7 @@ class DatabaseWrapper(BaseDatabaseWrapper):
self.connection.create_function("django_extract", 2, _sqlite_extract)
self.connection.create_function("django_date_trunc", 2, _sqlite_date_trunc)
self.connection.create_function("regexp", 2, _sqlite_regexp)
self.connection.create_function("django_format_dtdelta", 5, _sqlite_format_dtdelta)
connection_created.send(sender=self.__class__, connection=self)
return self.connection.cursor(factory=SQLiteCursorWrapper)
@ -260,6 +273,25 @@ def _sqlite_date_trunc(lookup_type, dt):
elif lookup_type == 'day':
return "%i-%02i-%02i 00:00:00" % (dt.year, dt.month, dt.day)
def _sqlite_format_dtdelta(dt, conn, days, secs, usecs):
try:
dt = util.typecast_timestamp(dt)
delta = datetime.timedelta(int(days), int(secs), int(usecs))
if conn.strip() == '+':
dt = dt + delta
else:
dt = dt - delta
except (ValueError, TypeError):
return None
if isinstance(dt, datetime.datetime):
rv = dt.strftime("%Y-%m-%d %H:%M:%S")
if dt.microsecond:
rv = "%s.%0.6d" % (rv, dt.microsecond)
else:
rv = dt.strftime("%Y-%m-%d")
return rv
def _sqlite_regexp(re_pattern, re_string):
import re
try:

43
django/db/models/expressions.py
View File

@ -1,4 +1,4 @@
from datetime import datetime
import datetime
from django.utils import tree
from django.utils.copycompat import deepcopy
@ -26,6 +26,9 @@ class ExpressionNode(tree.Node):
super(ExpressionNode, self).__init__(children, connector, negated)
def _combine(self, other, connector, reversed, node=None):
if isinstance(other, datetime.timedelta):
return DateModifierNode([self, other], connector)
if reversed:
obj = ExpressionNode([other], connector)
obj.add(node or self, connector)
@ -111,3 +114,41 @@ class F(ExpressionNode):
def evaluate(self, evaluator, qn, connection):
return evaluator.evaluate_leaf(self, qn, connection)
class DateModifierNode(ExpressionNode):
"""
Node that implements the following syntax:
filter(end_date__gt=F('start_date') + datetime.timedelta(days=3, seconds=200))
which translates into:
POSTGRES:
WHERE end_date > (start_date + INTERVAL '3 days 200 seconds')
MYSQL:
WHERE end_date > (start_date + INTERVAL '3 0:0:200:0' DAY_MICROSECOND)
ORACLE:
WHERE end_date > (start_date + INTERVAL '3 00:03:20.000000' DAY(1) TO SECOND(6))
SQLITE:
WHERE end_date > django_format_dtdelta(start_date, "+" "3", "200", "0")
(A custom function is used in order to preserve six digits of fractional
second information on sqlite, and to format both date and datetime values.)
Note that microsecond comparisons are not well supported with MySQL, since
MySQL does not store microsecond information.
Only adding and subtracting timedeltas is supported, attempts to use other
operations raise a TypeError.
"""
def __init__(self, children, connector, negated=False):
if len(children) != 2:
raise TypeError('Must specify a node and a timedelta.')
if not isinstance(children[1], datetime.timedelta):
raise TypeError('Second child must be a timedelta.')
if connector not in (self.ADD, self.SUB):
raise TypeError('Connector must be + or -, not %s' % connector)
super(DateModifierNode, self).__init__(children, connector, negated)
def evaluate(self, evaluator, qn, connection):
return evaluator.evaluate_date_modifier_node(self, qn, connection)

10
django/db/models/sql/expressions.py
View File

@ -85,3 +85,13 @@ class SQLEvaluator(object):
return col.as_sql(qn, connection), ()
else:
return '%s.%s' % (qn(col[0]), qn(col[1])), ()
def evaluate_date_modifier_node(self, node, qn, connection):
timedelta = node.children.pop()
sql, params = self.evaluate_node(node, qn, connection)
if timedelta.days == 0 and timedelta.seconds == 0 and \
timedelta.microseconds == 0:
return sql, params
return connection.ops.date_interval_sql(sql, node.connector, timedelta), params

3
docs/releases/1.3.txt
View File

@ -235,6 +235,9 @@ requests. These include:
providing a :class:`~django.template.RequestContext` by
default.
* Support for combining :ref:`F() expressions <query-expressions>`
with timedelta values when retrieving or updating database values.
.. _HTTPOnly: http://www.owasp.org/index.php/HTTPOnly
.. _backwards-incompatible-changes-1.3:

12
docs/topics/db/queries.txt
View File

@ -36,6 +36,7 @@ models, which comprise a Weblog application:
headline = models.CharField(max_length=255)
body_text = models.TextField()
pub_date = models.DateTimeField()
mod_date = models.DateTimeField()
authors = models.ManyToManyField(Author)
n_comments = models.IntegerField()
n_pingbacks = models.IntegerField()
@ -566,10 +567,19 @@ You can also use the double underscore notation to span relationships in
an ``F()`` object. An ``F()`` object with a double underscore will introduce
any joins needed to access the related object. For example, to retrieve all
the entries where the author's name is the same as the blog name, we could
issue the query:
issue the query::
>>> Entry.objects.filter(authors__name=F('blog__name'))
.. versionadded:: 1.3
For date and date/time fields, you can add or subtract a ``datetime.timedelta``
object. The following would return all entries that were modified more than 3 days
after they were published::
>>> from datetime import timedelta
>>> Entry.objects.filter(mod_date__gt=F('pub_date') + timedelta(days=3))
The pk lookup shortcut
----------------------

13
tests/regressiontests/expressions_regress/models.py
View File

@ -10,3 +10,16 @@ class Number(models.Model):
def __unicode__(self):
return u'%i, %.3f' % (self.integer, self.float)
class Experiment(models.Model):
name = models.CharField(max_length=24)
assigned = models.DateField()
completed = models.DateField()
start = models.DateTimeField()
end = models.DateTimeField()
class Meta:
ordering = ('name',)
def duration(self):
return self.end - self.start

207
tests/regressiontests/expressions_regress/tests.py
View File

@ -1,12 +1,14 @@
"""
Spanning tests for all the operations that F() expressions can perform.
"""
import datetime
from django.conf import settings
from django.db import models, DEFAULT_DB_ALIAS
from django.db import models, connection
from django.db.models import F
from django.test import TestCase, Approximate, skipUnlessDBFeature
from regressiontests.expressions_regress.models import Number
from regressiontests.expressions_regress.models import Number, Experiment
class ExpressionsRegressTests(TestCase):
@ -193,3 +195,204 @@ class ExpressionOperatorTests(TestCase):
self.assertEqual(Number.objects.get(pk=self.n.pk).integer, 47)
self.assertEqual(Number.objects.get(pk=self.n.pk).float, Approximate(15.500, places=3))
class FTimeDeltaTests(TestCase):
def setUp(self):
sday = datetime.date(2010, 6, 25)
stime = datetime.datetime(2010, 6, 25, 12, 15, 30, 747000)
midnight = datetime.time(0)
delta0 = datetime.timedelta(0)
delta1 = datetime.timedelta(microseconds=253000)
delta2 = datetime.timedelta(seconds=44)
delta3 = datetime.timedelta(hours=21, minutes=8)
delta4 = datetime.timedelta(days=10)
# Test data is set so that deltas and delays will be
# strictly increasing.
self.deltas = []
self.delays = []
self.days_long = []
# e0: started same day as assigned, zero duration
end = stime+delta0
e0 = Experiment.objects.create(name='e0', assigned=sday, start=stime,
end=end, completed=end.date())
self.deltas.append(delta0)
self.delays.append(e0.start-
datetime.datetime.combine(e0.assigned, midnight))
self.days_long.append(e0.completed-e0.assigned)
# e1: started one day after assigned, tiny duration, data
# set so that end time has no fractional seconds, which
# tests an edge case on sqlite. This Experiment is only
# included in the test data when the DB supports microsecond
# precision.
if connection.features.supports_microsecond_precision:
delay = datetime.timedelta(1)
end = stime + delay + delta1
e1 = Experiment.objects.create(name='e1', assigned=sday,
start=stime+delay, end=end, completed=end.date())
self.deltas.append(delta1)
self.delays.append(e1.start-
datetime.datetime.combine(e1.assigned, midnight))
self.days_long.append(e1.completed-e1.assigned)
# e2: started three days after assigned, small duration
end = stime+delta2
e2 = Experiment.objects.create(name='e2',
assigned=sday-datetime.timedelta(3), start=stime, end=end,
completed=end.date())
self.deltas.append(delta2)
self.delays.append(e2.start-
datetime.datetime.combine(e2.assigned, midnight))
self.days_long.append(e2.completed-e2.assigned)
# e3: started four days after assigned, medium duration
delay = datetime.timedelta(4)
end = stime + delay + delta3
e3 = Experiment.objects.create(name='e3',
assigned=sday, start=stime+delay, end=end, completed=end.date())
self.deltas.append(delta3)
self.delays.append(e3.start-
datetime.datetime.combine(e3.assigned, midnight))
self.days_long.append(e3.completed-e3.assigned)
# e4: started 10 days after assignment, long duration
end = stime + delta4
e4 = Experiment.objects.create(name='e4',
assigned=sday-datetime.timedelta(10), start=stime, end=end,
completed=end.date())
self.deltas.append(delta4)
self.delays.append(e4.start-
datetime.datetime.combine(e4.assigned, midnight))
self.days_long.append(e4.completed-e4.assigned)
self.expnames = [e.name for e in Experiment.objects.all()]
def test_delta_add(self):
for i in range(len(self.deltas)):
delta = self.deltas[i]
test_set = [e.name for e in
Experiment.objects.filter(end__lt=F('start')+delta)]
self.assertEqual(test_set, self.expnames[:i])
test_set = [e.name for e in
Experiment.objects.filter(end__lte=F('start')+delta)]
self.assertEqual(test_set, self.expnames[:i+1])
def test_delta_subtract(self):
for i in range(len(self.deltas)):
delta = self.deltas[i]
test_set = [e.name for e in
Experiment.objects.filter(start__gt=F('end')-delta)]
self.assertEqual(test_set, self.expnames[:i])
test_set = [e.name for e in
Experiment.objects.filter(start__gte=F('end')-delta)]
self.assertEqual(test_set, self.expnames[:i+1])
def test_exclude(self):
for i in range(len(self.deltas)):
delta = self.deltas[i]
test_set = [e.name for e in
Experiment.objects.exclude(end__lt=F('start')+delta)]
self.assertEqual(test_set, self.expnames[i:])
test_set = [e.name for e in
Experiment.objects.exclude(end__lte=F('start')+delta)]
self.assertEqual(test_set, self.expnames[i+1:])
def test_date_comparison(self):
for i in range(len(self.days_long)):
days = self.days_long[i]
test_set = [e.name for e in
Experiment.objects.filter(completed__lt=F('assigned')+days)]
self.assertEqual(test_set, self.expnames[:i])
test_set = [e.name for e in
Experiment.objects.filter(completed__lte=F('assigned')+days)]
self.assertEqual(test_set, self.expnames[:i+1])
@skipUnlessDBFeature("supports_mixed_date_datetime_comparisons")
def test_mixed_comparisons1(self):
for i in range(len(self.delays)):
delay = self.delays[i]
if not connection.features.supports_microsecond_precision:
delay = datetime.timedelta(delay.days, delay.seconds)
test_set = [e.name for e in
Experiment.objects.filter(assigned__gt=F('start')-delay)]
self.assertEqual(test_set, self.expnames[:i])
test_set = [e.name for e in
Experiment.objects.filter(assigned__gte=F('start')-delay)]
self.assertEqual(test_set, self.expnames[:i+1])
def test_mixed_comparisons2(self):
delays = [datetime.timedelta(delay.days) for delay in self.delays]
for i in range(len(delays)):
delay = delays[i]
test_set = [e.name for e in
Experiment.objects.filter(start__lt=F('assigned')+delay)]
self.assertEqual(test_set, self.expnames[:i])
test_set = [e.name for e in
Experiment.objects.filter(start__lte=F('assigned')+delay+
datetime.timedelta(1))]
self.assertEqual(test_set, self.expnames[:i+1])
def test_delta_update(self):
for i in range(len(self.deltas)):
delta = self.deltas[i]
exps = Experiment.objects.all()
expected_durations = [e.duration() for e in exps]
expected_starts = [e.start+delta for e in exps]
expected_ends = [e.end+delta for e in exps]
Experiment.objects.update(start=F('start')+delta, end=F('end')+delta)
exps = Experiment.objects.all()
new_starts = [e.start for e in exps]
new_ends = [e.end for e in exps]
new_durations = [e.duration() for e in exps]
self.assertEqual(expected_starts, new_starts)
self.assertEqual(expected_ends, new_ends)
self.assertEqual(expected_durations, new_durations)
def test_delta_invalid_op_mult(self):
raised = False
try:
r = repr(Experiment.objects.filter(end__lt=F('start')*self.deltas[0]))
except TypeError:
raised = True
self.assertTrue(raised, "TypeError not raised on attempt to multiply datetime by timedelta.")
def test_delta_invalid_op_div(self):
raised = False
try:
r = repr(Experiment.objects.filter(end__lt=F('start')/self.deltas[0]))
except TypeError:
raised = True
self.assertTrue(raised, "TypeError not raised on attempt to divide datetime by timedelta.")
def test_delta_invalid_op_mod(self):
raised = False
try:
r = repr(Experiment.objects.filter(end__lt=F('start')%self.deltas[0]))
except TypeError:
raised = True
self.assertTrue(raised, "TypeError not raised on attempt to modulo divide datetime by timedelta.")
def test_delta_invalid_op_and(self):
raised = False
try:
r = repr(Experiment.objects.filter(end__lt=F('start')&self.deltas[0]))
except TypeError:
raised = True
self.assertTrue(raised, "TypeError not raised on attempt to binary and a datetime with a timedelta.")
def test_delta_invalid_op_or(self):
raised = False
try:
r = repr(Experiment.objects.filter(end__lt=F('start')|self.deltas[0]))
except TypeError:
raised = True
self.assertTrue(raised, "TypeError not raised on attempt to binary or a datetime with a timedelta.")