def validate(self, value, model_instance):
if self.remote_field.parent_link:
return
super(ForeignKey, self).validate(value, model_instance)
if value is None:
return
using = router.db_for_read(model_instance.__class__, instance=model_instance)
qs = self.remote_field.model._default_manager.using(using).filter(
**{self.remote_field.field_name: value}
)
qs = qs.complex_filter(self.get_limit_choices_to())
if not qs.exists():
raise exceptions.ValidationError(
self.error_messages['invalid'],
code='invalid',
params={
'model': self.remote_field.model._meta.verbose_name, 'pk': value,
'field': self.remote_field.field_name, 'value': value,
}, # 'pk' is included for backwards compatibility
)
python类db_for_read()的实例源码
def has_key(self, key, version=None):
key = self.make_key(key, version=version)
self.validate_key(key)
db = router.db_for_read(self.cache_model_class)
connection = connections[db]
table = connection.ops.quote_name(self._table)
if settings.USE_TZ:
now = datetime.utcnow()
else:
now = datetime.now()
now = now.replace(microsecond=0)
with connection.cursor() as cursor:
cursor.execute("SELECT cache_key FROM %s "
"WHERE cache_key = %%s and expires > %%s" % table,
[key, connection.ops.adapt_datetimefield_value(now)])
return cursor.fetchone() is not None
def validate(self, value, model_instance):
if self.remote_field.parent_link:
return
super(ForeignKey, self).validate(value, model_instance)
if value is None:
return
using = router.db_for_read(self.remote_field.model, instance=model_instance)
qs = self.remote_field.model._default_manager.using(using).filter(
**{self.remote_field.field_name: value}
)
qs = qs.complex_filter(self.get_limit_choices_to())
if not qs.exists():
raise exceptions.ValidationError(
self.error_messages['invalid'],
code='invalid',
params={
'model': self.remote_field.model._meta.verbose_name, 'pk': value,
'field': self.remote_field.field_name, 'value': value,
}, # 'pk' is included for backwards compatibility
)
def has_key(self, key, version=None):
key = self.make_key(key, version=version)
self.validate_key(key)
db = router.db_for_read(self.cache_model_class)
connection = connections[db]
table = connection.ops.quote_name(self._table)
if settings.USE_TZ:
now = datetime.utcnow()
else:
now = datetime.now()
now = now.replace(microsecond=0)
with connection.cursor() as cursor:
cursor.execute("SELECT cache_key FROM %s "
"WHERE cache_key = %%s and expires > %%s" % table,
[key, connection.ops.adapt_datetimefield_value(now)])
return cursor.fetchone() is not None
def has_key(self, key, version=None):
key = self.make_key(key, version=version)
self.validate_key(key)
db = router.db_for_read(self.cache_model_class)
connection = connections[db]
table = connection.ops.quote_name(self._table)
if settings.USE_TZ:
now = datetime.utcnow()
else:
now = datetime.now()
now = now.replace(microsecond=0)
with connection.cursor() as cursor:
cursor.execute("SELECT cache_key FROM %s "
"WHERE cache_key = %%s and expires > %%s" % table,
[key, connection.ops.adapt_datetimefield_value(now)])
return cursor.fetchone() is not None
def has_key(self, key, version=None):
key = self.make_key(key, version=version)
self.validate_key(key)
db = router.db_for_read(self.cache_model_class)
table = connections[db].ops.quote_name(self._table)
if settings.USE_TZ:
now = datetime.utcnow()
else:
now = datetime.now()
now = now.replace(microsecond=0)
with connections[db].cursor() as cursor:
cursor.execute("SELECT cache_key FROM %s "
"WHERE cache_key = %%s and expires > %%s" % table,
[key, connections[db].ops.value_to_db_datetime(now)])
return cursor.fetchone() is not None
def validate(self, value, model_instance):
if self.rel.parent_link:
return
super(ForeignKey, self).validate(value, model_instance)
if value is None:
return
using = router.db_for_read(model_instance.__class__, instance=model_instance)
qs = self.rel.to._default_manager.using(using).filter(
**{self.rel.field_name: value}
)
qs = qs.complex_filter(self.get_limit_choices_to())
if not qs.exists():
raise exceptions.ValidationError(
self.error_messages['invalid'],
code='invalid',
params={
'model': self.rel.to._meta.verbose_name, 'pk': value,
'field': self.rel.field_name, 'value': value,
}, # 'pk' is included for backwards compatibility
)
def get(self, key, default=None, version=None):
key = self.make_key(key, version=version)
self.validate_key(key)
db = router.db_for_read(self.cache_model_class)
connection = connections[db]
table = connection.ops.quote_name(self._table)
with connection.cursor() as cursor:
cursor.execute("SELECT cache_key, value, expires FROM %s "
"WHERE cache_key = %%s" % table, [key])
row = cursor.fetchone()
if row is None:
return default
expires = row[2]
expression = models.Expression(output_field=models.DateTimeField())
for converter in (connection.ops.get_db_converters(expression) +
expression.get_db_converters(connection)):
expires = converter(expires, expression, connection, {})
if expires < timezone.now():
db = router.db_for_write(self.cache_model_class)
connection = connections[db]
with connection.cursor() as cursor:
cursor.execute("DELETE FROM %s "
"WHERE cache_key = %%s" % table, [key])
return default
value = connection.ops.process_clob(row[1])
return pickle.loads(base64.b64decode(force_bytes(value)))
def db(self):
return self._db or router.db_for_read(self.model, **self._hints)
#######################
# PROXIES TO QUERYSET #
#######################
def get(self, key, default=None, version=None):
key = self.make_key(key, version=version)
self.validate_key(key)
db = router.db_for_read(self.cache_model_class)
connection = connections[db]
table = connection.ops.quote_name(self._table)
with connection.cursor() as cursor:
cursor.execute("SELECT cache_key, value, expires FROM %s "
"WHERE cache_key = %%s" % table, [key])
row = cursor.fetchone()
if row is None:
return default
expires = row[2]
expression = models.Expression(output_field=models.DateTimeField())
for converter in (connection.ops.get_db_converters(expression) +
expression.get_db_converters(connection)):
expires = converter(expires, expression, connection, {})
if expires < timezone.now():
db = router.db_for_write(self.cache_model_class)
connection = connections[db]
with connection.cursor() as cursor:
cursor.execute("DELETE FROM %s "
"WHERE cache_key = %%s" % table, [key])
return default
value = connection.ops.process_clob(row[1])
return pickle.loads(base64.b64decode(force_bytes(value)))
def get(self, key, default=None, version=None):
key = self.make_key(key, version=version)
self.validate_key(key)
db = router.db_for_read(self.cache_model_class)
connection = connections[db]
table = connection.ops.quote_name(self._table)
with connection.cursor() as cursor:
cursor.execute("SELECT cache_key, value, expires FROM %s "
"WHERE cache_key = %%s" % table, [key])
row = cursor.fetchone()
if row is None:
return default
expires = row[2]
expression = models.Expression(output_field=models.DateTimeField())
for converter in (connection.ops.get_db_converters(expression) +
expression.get_db_converters(connection)):
expires = converter(expires, expression, connection, {})
if expires < timezone.now():
db = router.db_for_write(self.cache_model_class)
connection = connections[db]
with connection.cursor() as cursor:
cursor.execute("DELETE FROM %s "
"WHERE cache_key = %%s" % table, [key])
return default
value = connection.ops.process_clob(row[1])
return pickle.loads(base64.b64decode(force_bytes(value)))
def get(self, key, default=None, version=None):
key = self.make_key(key, version=version)
self.validate_key(key)
db = router.db_for_read(self.cache_model_class)
connection = connections[db]
table = connection.ops.quote_name(self._table)
with connection.cursor() as cursor:
cursor.execute("SELECT cache_key, value, expires FROM %s "
"WHERE cache_key = %%s" % table, [key])
row = cursor.fetchone()
if row is None:
return default
expires = row[2]
expression = models.Expression(output_field=models.DateTimeField())
for converter in (connection.ops.get_db_converters(expression) +
expression.get_db_converters(connection)):
expires = converter(expires, expression, connection, {})
if expires < timezone.now():
db = router.db_for_write(self.cache_model_class)
connection = connections[db]
with connection.cursor() as cursor:
cursor.execute("DELETE FROM %s "
"WHERE cache_key = %%s" % table, [key])
return default
value = connection.ops.process_clob(row[1])
return pickle.loads(base64.b64decode(force_bytes(value)))
def get(self, key, default=None, version=None):
key = self.make_key(key, version=version)
self.validate_key(key)
db = router.db_for_read(self.cache_model_class)
connection = connections[db]
table = connection.ops.quote_name(self._table)
with connection.cursor() as cursor:
cursor.execute("SELECT cache_key, value, expires FROM %s "
"WHERE cache_key = %%s" % table, [key])
row = cursor.fetchone()
if row is None:
return default
expires = row[2]
expression = models.Expression(output_field=models.DateTimeField())
for converter in (connection.ops.get_db_converters(expression) +
expression.get_db_converters(connection)):
expires = converter(expires, expression, connection, {})
if expires < timezone.now():
db = router.db_for_write(self.cache_model_class)
connection = connections[db]
with connection.cursor() as cursor:
cursor.execute("DELETE FROM %s "
"WHERE cache_key = %%s" % table, [key])
return default
value = connection.ops.process_clob(row[1])
return pickle.loads(base64.b64decode(force_bytes(value)))
def get(self, key, default=None, version=None):
key = self.make_key(key, version=version)
self.validate_key(key)
db = router.db_for_read(self.cache_model_class)
table = connections[db].ops.quote_name(self._table)
with connections[db].cursor() as cursor:
cursor.execute("SELECT cache_key, value, expires FROM %s "
"WHERE cache_key = %%s" % table, [key])
row = cursor.fetchone()
if row is None:
return default
now = timezone.now()
expires = row[2]
if connections[db].features.needs_datetime_string_cast and not isinstance(expires, datetime):
# Note: typecasting is needed by some 3rd party database backends.
# All core backends work without typecasting, so be careful about
# changes here - test suite will NOT pick regressions here.
expires = typecast_timestamp(str(expires))
if expires < now:
db = router.db_for_write(self.cache_model_class)
with connections[db].cursor() as cursor:
cursor.execute("DELETE FROM %s "
"WHERE cache_key = %%s" % table, [key])
return default
value = connections[db].ops.process_clob(row[1])
return pickle.loads(base64.b64decode(force_bytes(value)))
def get(self, key, default=None, version=None):
key = self.make_key(key, version=version)
self.validate_key(key)
db = router.db_for_read(self.cache_model_class)
connection = connections[db]
table = connection.ops.quote_name(self._table)
with connection.cursor() as cursor:
cursor.execute("SELECT cache_key, value, expires FROM %s "
"WHERE cache_key = %%s" % table, [key])
row = cursor.fetchone()
if row is None:
return default
expires = row[2]
expression = models.Expression(output_field=models.DateTimeField())
for converter in (connection.ops.get_db_converters(expression) +
expression.get_db_converters(connection)):
expires = converter(expires, expression, connection, {})
if expires < timezone.now():
db = router.db_for_write(self.cache_model_class)
connection = connections[db]
with connection.cursor() as cursor:
cursor.execute("DELETE FROM %s "
"WHERE cache_key = %%s" % table, [key])
return default
value = connection.ops.process_clob(row[1])
return pickle.loads(base64.b64decode(force_bytes(value)))
def get(self, key, default=None, version=None):
key = self.make_key(key, version=version)
self.validate_key(key)
db = router.db_for_read(self.cache_model_class)
connection = connections[db]
table = connection.ops.quote_name(self._table)
with connection.cursor() as cursor:
cursor.execute("SELECT cache_key, value, expires FROM %s "
"WHERE cache_key = %%s" % table, [key])
row = cursor.fetchone()
if row is None:
return default
expires = row[2]
expression = models.Expression(output_field=models.DateTimeField())
for converter in (connection.ops.get_db_converters(expression) +
expression.get_db_converters(connection)):
expires = converter(expires, expression, connection, {})
if expires < timezone.now():
db = router.db_for_write(self.cache_model_class)
connection = connections[db]
with connection.cursor() as cursor:
cursor.execute("DELETE FROM %s "
"WHERE cache_key = %%s" % table, [key])
return default
value = connection.ops.process_clob(row[1])
return pickle.loads(base64.b64decode(force_bytes(value)))
def get(self, key, default=None, version=None):
key = self.make_key(key, version=version)
self.validate_key(key)
db = router.db_for_read(self.cache_model_class)
table = connections[db].ops.quote_name(self._table)
with connections[db].cursor() as cursor:
cursor.execute("SELECT cache_key, value, expires FROM %s "
"WHERE cache_key = %%s" % table, [key])
row = cursor.fetchone()
if row is None:
return default
now = timezone.now()
expires = row[2]
if connections[db].features.needs_datetime_string_cast and not isinstance(expires, datetime):
# Note: typecasting is needed by some 3rd party database backends.
# All core backends work without typecasting, so be careful about
# changes here - test suite will NOT pick regressions here.
expires = typecast_timestamp(str(expires))
if expires < now:
db = router.db_for_write(self.cache_model_class)
with connections[db].cursor() as cursor:
cursor.execute("DELETE FROM %s "
"WHERE cache_key = %%s" % table, [key])
return default
value = connections[db].ops.process_clob(row[1])
return pickle.loads(base64.b64decode(force_bytes(value)))
def get(self, key, default=None, version=None):
key = self.make_key(key, version=version)
self.validate_key(key)
db = router.db_for_read(self.cache_model_class)
table = connections[db].ops.quote_name(self._table)
with connections[db].cursor() as cursor:
cursor.execute("SELECT cache_key, value, expires FROM %s "
"WHERE cache_key = %%s" % table, [key])
row = cursor.fetchone()
if row is None:
return default
now = timezone.now()
expires = row[2]
if connections[db].features.needs_datetime_string_cast and not isinstance(expires, datetime):
# Note: typecasting is needed by some 3rd party database backends.
# All core backends work without typecasting, so be careful about
# changes here - test suite will NOT pick regressions here.
expires = typecast_timestamp(str(expires))
if expires < now:
db = router.db_for_write(self.cache_model_class)
with connections[db].cursor() as cursor:
cursor.execute("DELETE FROM %s "
"WHERE cache_key = %%s" % table, [key])
return default
value = connections[db].ops.process_clob(row[1])
return pickle.loads(base64.b64decode(force_bytes(value)))
def get(self, key, default=None, version=None):
key = self.make_key(key, version=version)
self.validate_key(key)
db = router.db_for_read(self.cache_model_class)
connection = connections[db]
table = connection.ops.quote_name(self._table)
with connection.cursor() as cursor:
cursor.execute("SELECT cache_key, value, expires FROM %s "
"WHERE cache_key = %%s" % table, [key])
row = cursor.fetchone()
if row is None:
return default
expires = row[2]
expression = models.Expression(output_field=models.DateTimeField())
for converter in (connection.ops.get_db_converters(expression) +
expression.get_db_converters(connection)):
expires = converter(expires, expression, connection, {})
if expires < timezone.now():
db = router.db_for_write(self.cache_model_class)
connection = connections[db]
with connection.cursor() as cursor:
cursor.execute("DELETE FROM %s "
"WHERE cache_key = %%s" % table, [key])
return default
value = connection.ops.process_clob(row[1])
return pickle.loads(base64.b64decode(force_bytes(value)))
def get(self, key, default=None, version=None):
key = self.make_key(key, version=version)
self.validate_key(key)
db = router.db_for_read(self.cache_model_class)
connection = connections[db]
table = connection.ops.quote_name(self._table)
with connection.cursor() as cursor:
cursor.execute("SELECT cache_key, value, expires FROM %s "
"WHERE cache_key = %%s" % table, [key])
row = cursor.fetchone()
if row is None:
return default
expires = row[2]
expression = models.Expression(output_field=models.DateTimeField())
for converter in (connection.ops.get_db_converters(expression) +
expression.get_db_converters(connection)):
expires = converter(expires, expression, connection, {})
if expires < timezone.now():
db = router.db_for_write(self.cache_model_class)
connection = connections[db]
with connection.cursor() as cursor:
cursor.execute("DELETE FROM %s "
"WHERE cache_key = %%s" % table, [key])
return default
value = connection.ops.process_clob(row[1])
return pickle.loads(base64.b64decode(force_bytes(value)))
