def get_joins(self):
"""Returns a BaseTable and a list of Join objects that need to be added
to a QuerySet object that properly joins this model and the parent.
"""
# These arguments should match the spec of the Join object.
# See https://github.com/django/django/blob/1.8.7/django/db/models/sql/query.py#L896 # noqa
join_args = {
'table_name': None,
'parent_alias': None,
'table_alias': None,
'join_type': None,
'join_field': None,
'nullable': self.nullable,
}
joins = []
related_field = self.parent_model._meta.get_field(self.related_name)
# Setup two connections for m2m.
if self.relation == 'manytomany':
path = related_field.get_path_info()
copy1 = join_args.copy()
copy1.update({
'join_field': path[0].join_field,
'parent_alias': self.parent.db_table,
'table_name': self.m2m_db_table,
'join_type': LOUTER,
})
copy2 = join_args.copy()
copy2.update({
'join_field': path[1].join_field,
'parent_alias': self.m2m_db_table,
'table_name': self.db_table,
'join_type': LOUTER,
})
joins.append(Join(**copy1))
joins.append(Join(**copy2))
else:
copy = join_args.copy()
copy.update({
'table_name': self.db_table,
'parent_alias': self.parent.db_table,
'join_field': related_field,
'join_type': LOUTER if self.nullable else INNER,
})
joins.append(Join(**copy))
return BaseTable(self.parent.db_table, alias=None), joins
def order_by_translation(qs, fieldname, model=None):
"""
Order the QuerySet by the translated field, honoring the current and
fallback locales. Returns a new QuerySet.
The model being sorted needs a get_fallback() classmethod that describes
the fallback locale. get_fallback() can return a string or a Field.
"""
if fieldname.startswith('-'):
desc = True
fieldname = fieldname[1:]
else:
desc = False
qs = qs.all()
model = model or qs.model
field = model._meta.get_field(fieldname)
# Doing the manual joins is flying under Django's radar, so we need to make
# sure the initial alias (the main table) is set up.
if not qs.query.table_map:
qs.query.get_initial_alias()
# Force two new joins against the translation table, without reusing any
# aliases. We'll hook up the language fallbacks later.
# Passing `reuse=set()` force new joins, and passing `nullable=True`
# forces django to make LEFT OUTER JOINs (otherwise django, because we are
# building the query manually, does not detect that an inner join would
# remove results and happily simplifies the LEFT OUTER JOINs to
# INNER JOINs)
qs.query = qs.query.clone()
qs.query.__class__ = TranslationQuery
qs.query.fallback_model = model
t1 = qs.query.join(Join(field.remote_field.model._meta.db_table,
model._meta.db_table, None, LOUTER, field, True),
reuse=set())
t2 = qs.query.join(Join(field.remote_field.model._meta.db_table,
model._meta.db_table, None, LOUTER, field, True),
reuse=set())
qs.query.translation_aliases = {field: (t1, t2)}
f1, f2 = '%s.`localized_string`' % t1, '%s.`localized_string`' % t2
name = 'translated_%s' % field.column
ifnull = 'IFNULL(%s, %s)' % (f1, f2)
prefix = '-' if desc else ''
return qs.extra(select={name: ifnull},
where=['(%s IS NOT NULL OR %s IS NOT NULL)' % (f1, f2)],
order_by=[prefix + name])
def join_to_table(
table,
table2,
table_field,
table2_field,
queryset,
alias,
extra_restriction_func=lambda where_class, alias, related_alias: None):
"""
Add a join on `table2` to `queryset` (having table `table`).
"""
foreign_object = ForeignObject(to=table2,
from_fields=[None],
to_fields=[None],
rel=None)
foreign_object.opts = Options(table._meta)
foreign_object.opts.model = table
foreign_object.get_joining_columns = lambda: (
(table_field, table2_field), )
foreign_object.get_extra_restriction = extra_restriction_func
join = Join(table2._meta.db_table, table._meta.db_table, alias, LOUTER,
foreign_object, True)
queryset.query.join(join)
# hook for set alias
join.table_alias = alias
queryset.query.external_aliases.add(alias)
return queryset
def unique_together_left_join(queryset,
model,
link_field_name,
filter_field_name,
filter_value,
parent_model=None):
link_field = copy(model._meta.get_field(link_field_name).rel)
filter_field = model._meta.get_field(filter_field_name)
def restrictions(where_class, alias, related_alias):
cond = where_class()
cond.add(
filter_field.get_lookup('exact')(filter_field.get_col(alias),
filter_value), 'AND')
return cond
link_field.get_extra_restriction = restrictions
if parent_model is not None:
parent_alias = parent_model._meta.db_table
else:
parent_alias = queryset.query.get_initial_alias()
return queryset.query.join(
Join(model._meta.db_table, parent_alias, None, LOUTER, link_field,
True))
def __init__(self, model, trigger_alias, where=TriggerWhereNode):
super(TriggerFilterQuery, self).__init__(model, where)
self.trigger_alias = trigger_alias
try:
class JoinField():
def get_joining_columns(self):
return None
join = Join(None, None, None, None, JoinField(), False)
except:
join = JoinInfo(None, None, None, None, ((None, None), ), False,
None)
self.alias_map = {trigger_alias: join}
def _add_language_filter(self):
if self._language_filter_tag: # pragma: no cover
raise RuntimeError(
'Queryset is already tagged. This is a bug in hvad')
self._language_filter_tag = True
self.query.language_code = self._language_code
if self._language_code == 'all':
self._add_select_related()
elif self._language_fallbacks:
if self._raw_select_related:
raise NotImplementedError('Using select_related along with '
'fallbacks() is not supported')
languages = tuple(get_language() if lang is None else lang
for lang in (self._language_code, ) +
self._language_fallbacks)
masteratt = self.model._meta.get_field('master').attname
alias = self.query.join(
Join(self.model._meta.db_table, self.query.get_initial_alias(),
None, LOUTER,
BetterTranslationsField(languages,
master=masteratt), True))
add_alias_constraints(self, (self.model, alias), id__isnull=True)
self.query.add_filter(('%s__isnull' % masteratt, False))
if not self._skip_master_select and getattr(self, '_fields',
None) is None:
self.query.add_select_related(('master', ))
else:
language_code = self._language_code or get_language()
self.query.add_filter(('language_code', language_code))
self._add_select_related()
# if queryset is about to use the model's default ordering, we
# override that now with a translated version of the model's ordering
if self.query.default_ordering and not self.query.order_by:
ordering = self.shared_model._meta.ordering
self.query.order_by = self._translate_fieldnames(ordering or [])
return self
def add_where(self, queryset, host_table, included_table):
alias = None
nullable = True
join = Join(self.through_model._meta.db_table, included_table, None,
LOUTER, self.to_field, nullable)
alias, _ = queryset.query.table_alias(join.table_name, create=True)
join.table_alias = alias
queryset.query.alias_map[alias] = join
where = [
'{through_table}."{from_column}" = {host_table}."{host_column}"'.
format(through_table=join.table_alias,
from_column=self.from_field.field.column,
host_table=host_table,
host_column=self.from_field.target_field.column)
]
queryset.query.add_extra(None, None, where, None, None, None)
return queryset
def get(self, request, *args, **kwargs):
class JoinCols:
@staticmethod
def get_joining_columns():
return (('plan_id', 'plan_id'),)
@staticmethod
def get_extra_restriction(where_class, alias, related_alias):
return None
cart_items = self.cart_items.filter(option=0)
cart_items.query.join(Join(
AdvanceDiscount._meta.db_table, # table_name
CartItem._meta.db_table, # parent_alias
None, # table_alias
INNER, # join_type
JoinCols(), # join_field
False, # nullable
))
if cart_items.exists():
# If option == 0 and there is a discount to buy periods
# in advance, we will present multiple options to the user.
return http.HttpResponseRedirect(
reverse('saas_cart_periods', args=(self.organization,)))
return super(CartSeatsView, self).get(request, *args, **kwargs)
def join(self, qs=None):
'''
Join one queryset together with another using a temporary table. If
no queryset is used, it will use the current queryset and join that
to itself.
`Join` either uses the current queryset and effectively does a self-join to
create a new limited queryset OR it uses a querset given by the user.
The model of a given queryset needs to contain a valid foreign key to
the current queryset to perform a join. A new queryset is then created.
'''
to_field = 'id'
if qs:
fk = [
fk for fk in qs.model._meta.fields
if getattr(fk, 'related_model', None) == self.model
]
fk = fk[0] if fk else None
model_set = '{}_set'.format(self.model.__name__.lower())
key = fk or getattr(qs.model, model_set, None)
if not key:
raise ValueError('QuerySet is not related to current model')
try:
fk_column = key.column
except AttributeError:
fk_column = 'id'
to_field = key.field.column
qs = qs.only(fk_column)
# if we give a qs we need to keep the model qs to not lose anything
new_qs = self
else:
fk_column = 'id'
qs = self.only(fk_column)
new_qs = self.model.objects.all()
TABLE_NAME = 'temp_stuff'
query = self.get_quoted_query(qs.query)
sql = '''
DROP TABLE IF EXISTS {table_name};
DROP INDEX IF EXISTS {table_name}_id;
CREATE TEMPORARY TABLE {table_name} AS {query};
CREATE INDEX {table_name}_{fk_column} ON {table_name} ({fk_column});
'''.format(table_name=TABLE_NAME, fk_column=fk_column, query=str(query))
with connection.cursor() as cursor:
cursor.execute(sql)
class TempModel(models.Model):
temp_key = models.ForeignKey(
self.model,
on_delete=models.DO_NOTHING,
db_column=fk_column,
to_field=to_field
)
class Meta:
managed = False
db_table = TABLE_NAME
conn = Join(
table_name=TempModel._meta.db_table,
parent_alias=new_qs.query.get_initial_alias(),
table_alias=None,
join_type='INNER JOIN',
join_field=self.model.tempmodel_set.rel,
nullable=False
)
new_qs.query.join(conn, reuse=None)
return new_qs