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import datetime
from django.conf import settings
from django.core.exceptions import FieldError
from django.db.backends.util import truncate_name
from django.db.models.constants import LOOKUP_SEP
from django.db.models.query_utils import select_related_descend, QueryWrapper
from django.db.models.sql.constants import (SINGLE, MULTI, ORDER_DIR,
GET_ITERATOR_CHUNK_SIZE, SelectInfo)
from django.db.models.sql.datastructures import EmptyResultSet
from django.db.models.sql.expressions import SQLEvaluator
from django.db.models.sql.query import get_order_dir, Query
from django.db.transaction import TransactionManagementError
from django.db.utils import DatabaseError
from django.utils import six
from django.utils.six.moves import zip
from django.utils import timezone
class SQLCompiler(object):
def __init__(self, query, connection, using):
self.query = query
self.connection = connection
self.using = using
self.quote_cache = {}
# When ordering a queryset with distinct on a column not part of the
# select set, the ordering column needs to be added to the select
# clause. This information is needed both in SQL construction and
# masking away the ordering selects from the returned row.
self.ordering_aliases = []
self.ordering_params = []
def pre_sql_setup(self):
"""
Does any necessary class setup immediately prior to producing SQL. This
is for things that can't necessarily be done in __init__ because we
might not have all the pieces in place at that time.
# TODO: after the query has been executed, the altered state should be
# cleaned. We are not using a clone() of the query here.
"""
if not self.query.tables:
self.query.join((None, self.query.get_meta().db_table, None))
if (not self.query.select and self.query.default_cols and not
self.query.included_inherited_models):
self.query.setup_inherited_models()
if self.query.select_related and not self.query.related_select_cols:
self.fill_related_selections()
def quote_name_unless_alias(self, name):
"""
A wrapper around connection.ops.quote_name that doesn't quote aliases
for table names. This avoids problems with some SQL dialects that treat
quoted strings specially (e.g. PostgreSQL).
"""
if name in self.quote_cache:
return self.quote_cache[name]
if ((name in self.query.alias_map and name not in self.query.table_map) or
name in self.query.extra_select):
self.quote_cache[name] = name
return name
r = self.connection.ops.quote_name(name)
self.quote_cache[name] = r
return r
def as_sql(self, with_limits=True, with_col_aliases=False):
"""
Creates the SQL for this query. Returns the SQL string and list of
parameters.
If 'with_limits' is False, any limit/offset information is not included
in the query.
"""
if with_limits and self.query.low_mark == self.query.high_mark:
return '', ()
self.pre_sql_setup()
# After executing the query, we must get rid of any joins the query
# setup created. So, take note of alias counts before the query ran.
# However we do not want to get rid of stuff done in pre_sql_setup(),
# as the pre_sql_setup will modify query state in a way that forbids
# another run of it.
self.refcounts_before = self.query.alias_refcount.copy()
out_cols, s_params = self.get_columns(with_col_aliases)
ordering, o_params, ordering_group_by = self.get_ordering()
distinct_fields = self.get_distinct()
# This must come after 'select', 'ordering' and 'distinct' -- see
# docstring of get_from_clause() for details.
from_, f_params = self.get_from_clause()
qn = self.quote_name_unless_alias
where, w_params = self.query.where.as_sql(qn=qn, connection=self.connection)
having, h_params = self.query.having.as_sql(qn=qn, connection=self.connection)
having_group_by = self.query.having.get_cols()
params = []
for val in six.itervalues(self.query.extra_select):
params.extend(val[1])
result = ['SELECT']
if self.query.distinct:
result.append(self.connection.ops.distinct_sql(distinct_fields))
params.extend(o_params)
result.append(', '.join(out_cols + self.ordering_aliases))
params.extend(s_params)
params.extend(self.ordering_params)
result.append('FROM')
result.extend(from_)
params.extend(f_params)
if where:
result.append('WHERE %s' % where)
params.extend(w_params)
grouping, gb_params = self.get_grouping(having_group_by, ordering_group_by)
if grouping:
if distinct_fields:
raise NotImplementedError(
"annotate() + distinct(fields) not implemented.")
if not ordering:
ordering = self.connection.ops.force_no_ordering()
result.append('GROUP BY %s' % ', '.join(grouping))
params.extend(gb_params)
if having:
result.append('HAVING %s' % having)
params.extend(h_params)
if ordering:
result.append('ORDER BY %s' % ', '.join(ordering))
if with_limits:
if self.query.high_mark is not None:
result.append('LIMIT %d' % (self.query.high_mark - self.query.low_mark))
if self.query.low_mark:
if self.query.high_mark is None:
val = self.connection.ops.no_limit_value()
if val:
result.append('LIMIT %d' % val)
result.append('OFFSET %d' % self.query.low_mark)
if self.query.select_for_update and self.connection.features.has_select_for_update:
if self.connection.get_autocommit():
raise TransactionManagementError("select_for_update cannot be used outside of a transaction.")
# If we've been asked for a NOWAIT query but the backend does not support it,
# raise a DatabaseError otherwise we could get an unexpected deadlock.
nowait = self.query.select_for_update_nowait
if nowait and not self.connection.features.has_select_for_update_nowait:
raise DatabaseError('NOWAIT is not supported on this database backend.')
result.append(self.connection.ops.for_update_sql(nowait=nowait))
# Finally do cleanup - get rid of the joins we created above.
self.query.reset_refcounts(self.refcounts_before)
return ' '.join(result), tuple(params)
def as_nested_sql(self):
"""
Perform the same functionality as the as_sql() method, returning an
SQL string and parameters. However, the alias prefixes are bumped
beforehand (in a copy -- the current query isn't changed), and any
ordering is removed if the query is unsliced.
Used when nesting this query inside another.
"""
obj = self.query.clone()
if obj.low_mark == 0 and obj.high_mark is None:
# If there is no slicing in use, then we can safely drop all ordering
obj.clear_ordering(True)
obj.bump_prefix()
return obj.get_compiler(connection=self.connection).as_sql()
def get_columns(self, with_aliases=False):
"""
Returns the list of columns to use in the select statement, as well as
a list any extra parameters that need to be included. If no columns
have been specified, returns all columns relating to fields in the
model.
If 'with_aliases' is true, any column names that are duplicated
(without the table names) are given unique aliases. This is needed in
some cases to avoid ambiguity with nested queries.
"""
qn = self.quote_name_unless_alias
qn2 = self.connection.ops.quote_name
result = ['(%s) AS %s' % (col[0], qn2(alias)) for alias, col in six.iteritems(self.query.extra_select)]
params = []
aliases = set(self.query.extra_select.keys())
if with_aliases:
col_aliases = aliases.copy()
else:
col_aliases = set()
if self.query.select:
only_load = self.deferred_to_columns()
for col, _ in self.query.select:
if isinstance(col, (list, tuple)):
alias, column = col
table = self.query.alias_map[alias].table_name
if table in only_load and column not in only_load[table]:
continue
r = '%s.%s' % (qn(alias), qn(column))
if with_aliases:
if col[1] in col_aliases:
c_alias = 'Col%d' % len(col_aliases)
result.append('%s AS %s' % (r, c_alias))
aliases.add(c_alias)
col_aliases.add(c_alias)
else:
result.append('%s AS %s' % (r, qn2(col[1])))
aliases.add(r)
col_aliases.add(col[1])
else:
result.append(r)
aliases.add(r)
col_aliases.add(col[1])
else:
col_sql, col_params = col.as_sql(qn, self.connection)
result.append(col_sql)
params.extend(col_params)
if hasattr(col, 'alias'):
aliases.add(col.alias)
col_aliases.add(col.alias)
elif self.query.default_cols:
cols, new_aliases = self.get_default_columns(with_aliases,
col_aliases)
result.extend(cols)
aliases.update(new_aliases)
max_name_length = self.connection.ops.max_name_length()
for alias, aggregate in self.query.aggregate_select.items():
agg_sql, agg_params = aggregate.as_sql(qn, self.connection)
if alias is None:
result.append(agg_sql)
else:
result.append('%s AS %s' % (agg_sql, qn(truncate_name(alias, max_name_length))))
params.extend(agg_params)
for (table, col), _ in self.query.related_select_cols:
r = '%s.%s' % (qn(table), qn(col))
if with_aliases and col in col_aliases:
c_alias = 'Col%d' % len(col_aliases)
result.append('%s AS %s' % (r, c_alias))
aliases.add(c_alias)
col_aliases.add(c_alias)
else:
result.append(r)
aliases.add(r)
col_aliases.add(col)
self._select_aliases = aliases
return result, params
def get_default_columns(self, with_aliases=False, col_aliases=None,
start_alias=None, opts=None, as_pairs=False, from_parent=None):
"""
Computes the default columns for selecting every field in the base
model. Will sometimes be called to pull in related models (e.g. via
select_related), in which case "opts" and "start_alias" will be given
to provide a starting point for the traversal.
Returns a list of strings, quoted appropriately for use in SQL
directly, as well as a set of aliases used in the select statement (if
'as_pairs' is True, returns a list of (alias, col_name) pairs instead
of strings as the first component and None as the second component).
"""
result = []
if opts is None:
opts = self.query.get_meta()
qn = self.quote_name_unless_alias
qn2 = self.connection.ops.quote_name
aliases = set()
only_load = self.deferred_to_columns()
if not start_alias:
start_alias = self.query.get_initial_alias()
# The 'seen_models' is used to optimize checking the needed parent
# alias for a given field. This also includes None -> start_alias to
# be used by local fields.
seen_models = {None: start_alias}
for field, model in opts.get_concrete_fields_with_model():
if from_parent and model is not None and issubclass(from_parent, model):
# Avoid loading data for already loaded parents.
continue
alias = self.query.join_parent_model(opts, model, start_alias,
seen_models)
table = self.query.alias_map[alias].table_name
if table in only_load and field.column not in only_load[table]:
continue
if as_pairs:
result.append((alias, field))
aliases.add(alias)
continue
if with_aliases and field.column in col_aliases:
c_alias = 'Col%d' % len(col_aliases)
result.append('%s.%s AS %s' % (qn(alias),
qn2(field.column), c_alias))
col_aliases.add(c_alias)
aliases.add(c_alias)
else:
r = '%s.%s' % (qn(alias), qn2(field.column))
result.append(r)
aliases.add(r)
if with_aliases:
col_aliases.add(field.column)
return result, aliases
def get_distinct(self):
"""
Returns a quoted list of fields to use in DISTINCT ON part of the query.
Note that this method can alter the tables in the query, and thus it
must be called before get_from_clause().
"""
qn = self.quote_name_unless_alias
qn2 = self.connection.ops.quote_name
result = []
opts = self.query.get_meta()
for name in self.query.distinct_fields:
parts = name.split(LOOKUP_SEP)
field, cols, alias, _, _ = self._setup_joins(parts, opts, None)
cols, alias = self._final_join_removal(cols, alias)
for col in cols:
result.append("%s.%s" % (qn(alias), qn2(col)))
return result
def get_ordering(self):
"""
Returns a tuple containing a list representing the SQL elements in the
"order by" clause, and the list of SQL elements that need to be added
to the GROUP BY clause as a result of the ordering.
Also sets the ordering_aliases attribute on this instance to a list of
extra aliases needed in the select.
Determining the ordering SQL can change the tables we need to include,
so this should be run *before* get_from_clause().
"""
if self.query.extra_order_by:
ordering = self.query.extra_order_by
elif not self.query.default_ordering:
ordering = self.query.order_by
else:
ordering = (self.query.order_by
or self.query.get_meta().ordering
or [])
qn = self.quote_name_unless_alias
qn2 = self.connection.ops.quote_name
distinct = self.query.distinct
select_aliases = self._select_aliases
result = []
group_by = []
ordering_aliases = []
if self.query.standard_ordering:
asc, desc = ORDER_DIR['ASC']
else:
asc, desc = ORDER_DIR['DESC']
# It's possible, due to model inheritance, that normal usage might try
# to include the same field more than once in the ordering. We track
# the table/column pairs we use and discard any after the first use.
processed_pairs = set()
params = []
ordering_params = []
for pos, field in enumerate(ordering):
if field == '?':
result.append(self.connection.ops.random_function_sql())
continue
if isinstance(field, int):
if field < 0:
order = desc
field = -field
else:
order = asc
result.append('%s %s' % (field, order))
group_by.append((str(field), []))
continue
col, order = get_order_dir(field, asc)
if col in self.query.aggregate_select:
result.append('%s %s' % (qn(col), order))
continue
if '.' in field:
# This came in through an extra(order_by=...) addition. Pass it
# on verbatim.
table, col = col.split('.', 1)
if (table, col) not in processed_pairs:
elt = '%s.%s' % (qn(table), col)
processed_pairs.add((table, col))
if not distinct or elt in select_aliases:
result.append('%s %s' % (elt, order))
group_by.append((elt, []))
elif get_order_dir(field)[0] not in self.query.extra:
# 'col' is of the form 'field' or 'field1__field2' or
# '-field1__field2__field', etc.
for table, cols, order in self.find_ordering_name(field,
self.query.get_meta(), default_order=asc):
for col in cols:
if (table, col) not in processed_pairs:
elt = '%s.%s' % (qn(table), qn2(col))
processed_pairs.add((table, col))
if distinct and elt not in select_aliases:
ordering_aliases.append(elt)
result.append('%s %s' % (elt, order))
group_by.append((elt, []))
else:
elt = qn2(col)
if col not in self.query.extra_select:
sql = "(%s) AS %s" % (self.query.extra[col][0], elt)
ordering_aliases.append(sql)
ordering_params.extend(self.query.extra[col][1])
else:
if distinct and col not in select_aliases:
ordering_aliases.append(elt)
ordering_params.extend(params)
result.append('%s %s' % (elt, order))
group_by.append(self.query.extra[col])
self.ordering_aliases = ordering_aliases
self.ordering_params = ordering_params
return result, params, group_by
def find_ordering_name(self, name, opts, alias=None, default_order='ASC',
already_seen=None):
"""
Returns the table alias (the name might be ambiguous, the alias will
not be) and column name for ordering by the given 'name' parameter.
The 'name' is of the form 'field1__field2__...__fieldN'.
"""
name, order = get_order_dir(name, default_order)
pieces = name.split(LOOKUP_SEP)
field, cols, alias, joins, opts = self._setup_joins(pieces, opts, alias)
# If we get to this point and the field is a relation to another model,
# append the default ordering for that model.
if field.rel and len(joins) > 1 and opts.ordering:
# Firstly, avoid infinite loops.
if not already_seen:
already_seen = set()
join_tuple = tuple([self.query.alias_map[j].table_name for j in joins])
if join_tuple in already_seen:
raise FieldError('Infinite loop caused by ordering.')
already_seen.add(join_tuple)
results = []
for item in opts.ordering:
results.extend(self.find_ordering_name(item, opts, alias,
order, already_seen))
return results
cols, alias = self._final_join_removal(cols, alias)
return [(alias, cols, order)]
def _setup_joins(self, pieces, opts, alias):
"""
A helper method for get_ordering and get_distinct. This method will
call query.setup_joins, handle refcounts and then promote the joins.
Note that get_ordering and get_distinct must produce same target
columns on same input, as the prefixes of get_ordering and get_distinct
must match. Executing SQL where this is not true is an error.
"""
if not alias:
alias = self.query.get_initial_alias()
field, targets, opts, joins, _ = self.query.setup_joins(
pieces, opts, alias)
# We will later on need to promote those joins that were added to the
# query afresh above.
joins_to_promote = [j for j in joins if self.query.alias_refcount[j] < 2]
alias = joins[-1]
cols = [target.column for target in targets]
if not field.rel:
# To avoid inadvertent trimming of a necessary alias, use the
# refcount to show that we are referencing a non-relation field on
# the model.
self.query.ref_alias(alias)
# Must use left outer joins for nullable fields and their relations.
# Ordering or distinct must not affect the returned set, and INNER
# JOINS for nullable fields could do this.
self.query.promote_joins(joins_to_promote)
return field, cols, alias, joins, opts
def _final_join_removal(self, cols, alias):
"""
A helper method for get_distinct and get_ordering. This method will
trim extra not-needed joins from the tail of the join chain.
This is very similar to what is done in trim_joins, but we will
trim LEFT JOINS here. It would be a good idea to consolidate this
method and query.trim_joins().
"""
if alias:
while 1:
join = self.query.alias_map[alias]
lhs_cols, rhs_cols = zip(*[(lhs_col, rhs_col) for lhs_col, rhs_col in join.join_cols])
if set(cols) != set(rhs_cols):
break
cols = [lhs_cols[rhs_cols.index(col)] for col in cols]
self.query.unref_alias(alias)
alias = join.lhs_alias
return cols, alias
def get_from_clause(self):
"""
Returns a list of strings that are joined together to go after the
"FROM" part of the query, as well as a list any extra parameters that
need to be included. Sub-classes, can override this to create a
from-clause via a "select".
This should only be called after any SQL construction methods that
might change the tables we need. This means the select columns,
ordering and distinct must be done first.
"""
result = []
qn = self.quote_name_unless_alias
qn2 = self.connection.ops.quote_name
first = True
from_params = []
for alias in self.query.tables:
if not self.query.alias_refcount[alias]:
continue
try:
name, alias, join_type, lhs, join_cols, _, join_field = self.query.alias_map[alias]
except KeyError:
# Extra tables can end up in self.tables, but not in the
# alias_map if they aren't in a join. That's OK. We skip them.
continue
alias_str = '' if alias == name else (' %s' % alias)
if join_type and not first:
extra_cond = join_field.get_extra_restriction(
self.query.where_class, alias, lhs)
if extra_cond:
extra_sql, extra_params = extra_cond.as_sql(
qn, self.connection)
extra_sql = 'AND (%s)' % extra_sql
from_params.extend(extra_params)
else:
extra_sql = ""
result.append('%s %s%s ON ('
% (join_type, qn(name), alias_str))
for index, (lhs_col, rhs_col) in enumerate(join_cols):
if index != 0:
result.append(' AND ')
result.append('%s.%s = %s.%s' %
(qn(lhs), qn2(lhs_col), qn(alias), qn2(rhs_col)))
result.append('%s)' % extra_sql)
else:
connector = '' if first else ', '
result.append('%s%s%s' % (connector, qn(name), alias_str))
first = False
for t in self.query.extra_tables:
alias, unused = self.query.table_alias(t)
# Only add the alias if it's not already present (the table_alias()
# calls increments the refcount, so an alias refcount of one means
# this is the only reference.
if alias not in self.query.alias_map or self.query.alias_refcount[alias] == 1:
connector = '' if first else ', '
result.append('%s%s' % (connector, qn(alias)))
first = False
return result, from_params
def get_grouping(self, having_group_by, ordering_group_by):
"""
Returns a tuple representing the SQL elements in the "group by" clause.
"""
qn = self.quote_name_unless_alias
result, params = [], []
if self.query.group_by is not None:
select_cols = self.query.select + self.query.related_select_cols
# Just the column, not the fields.
select_cols = [s[0] for s in select_cols]
if (len(self.query.get_meta().concrete_fields) == len(self.query.select)
and self.connection.features.allows_group_by_pk):
self.query.group_by = [
(self.query.get_meta().db_table, self.query.get_meta().pk.column)
]
select_cols = []
seen = set()
cols = self.query.group_by + having_group_by + select_cols
for col in cols:
col_params = ()
if isinstance(col, (list, tuple)):
sql = '%s.%s' % (qn(col[0]), qn(col[1]))
elif hasattr(col, 'as_sql'):
sql, col_params = col.as_sql(qn, self.connection)
else:
sql = '(%s)' % str(col)
if sql not in seen:
result.append(sql)
params.extend(col_params)
seen.add(sql)
# Still, we need to add all stuff in ordering (except if the backend can
# group by just by PK).
if ordering_group_by and not self.connection.features.allows_group_by_pk:
for order, order_params in ordering_group_by:
# Even if we have seen the same SQL string, it might have
# different params, so, we add same SQL in "has params" case.
if order not in seen or order_params:
result.append(order)
params.extend(order_params)
seen.add(order)
# Unconditionally add the extra_select items.
for extra_select, extra_params in self.query.extra_select.values():
sql = '(%s)' % str(extra_select)
result.append(sql)
params.extend(extra_params)
return result, params
def fill_related_selections(self, opts=None, root_alias=None, cur_depth=1,
requested=None, restricted=None, nullable=None):
"""
Fill in the information needed for a select_related query. The current
depth is measured as the number of connections away from the root model
(for example, cur_depth=1 means we are looking at models with direct
connections to the root model).
"""
if not restricted and self.query.max_depth and cur_depth > self.query.max_depth:
# We've recursed far enough; bail out.
return
if not opts:
opts = self.query.get_meta()
root_alias = self.query.get_initial_alias()
self.query.related_select_cols = []
only_load = self.query.get_loaded_field_names()
# Setup for the case when only particular related fields should be
# included in the related selection.
if requested is None:
if isinstance(self.query.select_related, dict):
requested = self.query.select_related
restricted = True
else:
restricted = False
for f, model in opts.get_fields_with_model():
# The get_fields_with_model() returns None for fields that live
# in the field's local model. So, for those fields we want to use
# the f.model - that is the field's local model.
field_model = model or f.model
if not select_related_descend(f, restricted, requested,
only_load.get(field_model)):
continue
promote = nullable or f.null
_, _, _, joins, _ = self.query.setup_joins(
[f.name], opts, root_alias, outer_if_first=promote)
alias = joins[-1]
columns, _ = self.get_default_columns(start_alias=alias,
opts=f.rel.to._meta, as_pairs=True)
self.query.related_select_cols.extend(
SelectInfo((col[0], col[1].column), col[1]) for col in columns)
if restricted:
next = requested.get(f.name, {})
else:
next = False
new_nullable = f.null or promote
self.fill_related_selections(f.rel.to._meta, alias, cur_depth + 1,
next, restricted, new_nullable)
if restricted:
related_fields = [
(o.field, o.model)
for o in opts.get_all_related_objects()
if o.field.unique
]
for f, model in related_fields:
if not select_related_descend(f, restricted, requested,
only_load.get(model), reverse=True):
continue
_, _, _, joins, _ = self.query.setup_joins(
[f.related_query_name()], opts, root_alias, outer_if_first=True)
alias = joins[-1]
from_parent = (opts.model if issubclass(model, opts.model)
else None)
columns, _ = self.get_default_columns(start_alias=alias,
opts=model._meta, as_pairs=True, from_parent=from_parent)
self.query.related_select_cols.extend(
SelectInfo((col[0], col[1].column), col[1]) for col in columns)
next = requested.get(f.related_query_name(), {})
# Use True here because we are looking at the _reverse_ side of
# the relation, which is always nullable.
new_nullable = True
self.fill_related_selections(model._meta, alias, cur_depth + 1,
next, restricted, new_nullable)
def deferred_to_columns(self):
"""
Converts the self.deferred_loading data structure to mapping of table
names to sets of column names which are to be loaded. Returns the
dictionary.
"""
columns = {}
self.query.deferred_to_data(columns, self.query.deferred_to_columns_cb)
return columns
def results_iter(self):
"""
Returns an iterator over the results from executing this query.
"""
resolve_columns = hasattr(self, 'resolve_columns')
fields = None
has_aggregate_select = bool(self.query.aggregate_select)
for rows in self.execute_sql(MULTI):
for row in rows:
if has_aggregate_select:
loaded_fields = self.query.get_loaded_field_names().get(self.query.model, set()) or self.query.select
aggregate_start = len(self.query.extra_select) + len(loaded_fields)
aggregate_end = aggregate_start + len(self.query.aggregate_select)
if resolve_columns:
if fields is None:
# We only set this up here because
# related_select_cols isn't populated until
# execute_sql() has been called.
# We also include types of fields of related models that
# will be included via select_related() for the benefit
# of MySQL/MySQLdb when boolean fields are involved
# (#15040).
# This code duplicates the logic for the order of fields
# found in get_columns(). It would be nice to clean this up.
if self.query.select:
fields = [f.field for f in self.query.select]
elif self.query.default_cols:
fields = self.query.get_meta().concrete_fields
else:
fields = []
fields = fields + [f.field for f in self.query.related_select_cols]
# If the field was deferred, exclude it from being passed
# into `resolve_columns` because it wasn't selected.
only_load = self.deferred_to_columns()
if only_load:
fields = [f for f in fields if f.model._meta.db_table not in only_load or
f.column in only_load[f.model._meta.db_table]]
if has_aggregate_select:
# pad None in to fields for aggregates
fields = fields[:aggregate_start] + [
None for x in range(0, aggregate_end - aggregate_start)
] + fields[aggregate_start:]
row = self.resolve_columns(row, fields)
if has_aggregate_select:
row = tuple(row[:aggregate_start]) + tuple([
self.query.resolve_aggregate(value, aggregate, self.connection)
for (alias, aggregate), value
in zip(self.query.aggregate_select.items(), row[aggregate_start:aggregate_end])
]) + tuple(row[aggregate_end:])
yield row
def execute_sql(self, result_type=MULTI):
"""
Run the query against the database and returns the result(s). The
return value is a single data item if result_type is SINGLE, or an
iterator over the results if the result_type is MULTI.
result_type is either MULTI (use fetchmany() to retrieve all rows),
SINGLE (only retrieve a single row), or None. In this last case, the
cursor is returned if any query is executed, since it's used by
subclasses such as InsertQuery). It's possible, however, that no query
is needed, as the filters describe an empty set. In that case, None is
returned, to avoid any unnecessary database interaction.
"""
try:
sql, params = self.as_sql()
if not sql:
raise EmptyResultSet
except EmptyResultSet:
if result_type == MULTI:
return iter([])
else:
return
cursor = self.connection.cursor()
cursor.execute(sql, params)
if not result_type:
return cursor
if result_type == SINGLE:
if self.ordering_aliases:
return cursor.fetchone()[:-len(self.ordering_aliases)]
return cursor.fetchone()
# The MULTI case.
if self.ordering_aliases:
result = order_modified_iter(cursor, len(self.ordering_aliases),
self.connection.features.empty_fetchmany_value)
else:
result = iter((lambda: cursor.fetchmany(GET_ITERATOR_CHUNK_SIZE)),
self.connection.features.empty_fetchmany_value)
if not self.connection.features.can_use_chunked_reads:
# If we are using non-chunked reads, we return the same data
# structure as normally, but ensure it is all read into memory
# before going any further.
return list(result)
return result
def as_subquery_condition(self, alias, columns, qn):
qn2 = self.connection.ops.quote_name
if len(columns) == 1:
sql, params = self.as_sql()
return '%s.%s IN (%s)' % (qn(alias), qn2(columns[0]), sql), params
for index, select_col in enumerate(self.query.select):
lhs = '%s.%s' % (qn(select_col.col[0]), qn2(select_col.col[1]))
rhs = '%s.%s' % (qn(alias), qn2(columns[index]))
self.query.where.add(
QueryWrapper('%s = %s' % (lhs, rhs), []), 'AND')
sql, params = self.as_sql()
return 'EXISTS (%s)' % sql, params
class SQLInsertCompiler(SQLCompiler):
def __init__(self, *args, **kwargs):
self.return_id = False
super(SQLInsertCompiler, self).__init__(*args, **kwargs)
def placeholder(self, field, val):
if field is None:
# A field value of None means the value is raw.
return val
elif hasattr(field, 'get_placeholder'):
# Some fields (e.g. geo fields) need special munging before
# they can be inserted.
return field.get_placeholder(val, self.connection)
else:
# Return the common case for the placeholder
return '%s'
def as_sql(self):
# We don't need quote_name_unless_alias() here, since these are all
# going to be column names (so we can avoid the extra overhead).
qn = self.connection.ops.quote_name
opts = self.query.get_meta()
result = ['INSERT INTO %s' % qn(opts.db_table)]
has_fields = bool(self.query.fields)
fields = self.query.fields if has_fields else [opts.pk]
result.append('(%s)' % ', '.join([qn(f.column) for f in fields]))
if has_fields:
params = values = [
[
f.get_db_prep_save(getattr(obj, f.attname) if self.query.raw else f.pre_save(obj, True), connection=self.connection)
for f in fields
]
for obj in self.query.objs
]
else:
values = [[self.connection.ops.pk_default_value()] for obj in self.query.objs]
params = [[]]
fields = [None]
can_bulk = (not any(hasattr(field, "get_placeholder") for field in fields) and
not self.return_id and self.connection.features.has_bulk_insert)
if can_bulk:
placeholders = [["%s"] * len(fields)]
else:
placeholders = [
[self.placeholder(field, v) for field, v in zip(fields, val)]
for val in values
]
# Oracle Spatial needs to remove some values due to #10888
params = self.connection.ops.modify_insert_params(placeholders, params)
if self.return_id and self.connection.features.can_return_id_from_insert:
params = params[0]
col = "%s.%s" % (qn(opts.db_table), qn(opts.pk.column))
result.append("VALUES (%s)" % ", ".join(placeholders[0]))
r_fmt, r_params = self.connection.ops.return_insert_id()
# Skip empty r_fmt to allow subclasses to customize behaviour for
# 3rd party backends. Refs #19096.
if r_fmt:
result.append(r_fmt % col)
params += r_params
return [(" ".join(result), tuple(params))]
if can_bulk:
result.append(self.connection.ops.bulk_insert_sql(fields, len(values)))
return [(" ".join(result), tuple([v for val in values for v in val]))]
else:
return [
(" ".join(result + ["VALUES (%s)" % ", ".join(p)]), vals)
for p, vals in zip(placeholders, params)
]
def execute_sql(self, return_id=False):
assert not (return_id and len(self.query.objs) != 1)
self.return_id = return_id
cursor = self.connection.cursor()
for sql, params in self.as_sql():
cursor.execute(sql, params)
if not (return_id and cursor):
return
if self.connection.features.can_return_id_from_insert:
return self.connection.ops.fetch_returned_insert_id(cursor)
return self.connection.ops.last_insert_id(cursor,
self.query.get_meta().db_table, self.query.get_meta().pk.column)
class SQLDeleteCompiler(SQLCompiler):
def as_sql(self):
"""
Creates the SQL for this query. Returns the SQL string and list of
parameters.
"""
assert len(self.query.tables) == 1, \
"Can only delete from one table at a time."
qn = self.quote_name_unless_alias
result = ['DELETE FROM %s' % qn(self.query.tables[0])]
where, params = self.query.where.as_sql(qn=qn, connection=self.connection)
if where:
result.append('WHERE %s' % where)
return ' '.join(result), tuple(params)
class SQLUpdateCompiler(SQLCompiler):
def as_sql(self):
"""
Creates the SQL for this query. Returns the SQL string and list of
parameters.
"""
self.pre_sql_setup()
if not self.query.values:
return '', ()
table = self.query.tables[0]
qn = self.quote_name_unless_alias
result = ['UPDATE %s' % qn(table)]
result.append('SET')
values, update_params = [], []
for field, model, val in self.query.values:
if hasattr(val, 'prepare_database_save'):
val = val.prepare_database_save(field)
else:
val = field.get_db_prep_save(val, connection=self.connection)
# Getting the placeholder for the field.
if hasattr(field, 'get_placeholder'):
placeholder = field.get_placeholder(val, self.connection)
else:
placeholder = '%s'
if hasattr(val, 'evaluate'):
val = SQLEvaluator(val, self.query, allow_joins=False)
name = field.column
if hasattr(val, 'as_sql'):
sql, params = val.as_sql(qn, self.connection)
values.append('%s = %s' % (qn(name), sql))
update_params.extend(params)
elif val is not None:
values.append('%s = %s' % (qn(name), placeholder))
update_params.append(val)
else:
values.append('%s = NULL' % qn(name))
if not values:
return '', ()
result.append(', '.join(values))
where, params = self.query.where.as_sql(qn=qn, connection=self.connection)
if where:
result.append('WHERE %s' % where)
return ' '.join(result), tuple(update_params + params)
def execute_sql(self, result_type):
"""
Execute the specified update. Returns the number of rows affected by
the primary update query. The "primary update query" is the first
non-empty query that is executed. Row counts for any subsequent,
related queries are not available.
"""
cursor = super(SQLUpdateCompiler, self).execute_sql(result_type)
rows = cursor.rowcount if cursor else 0
is_empty = cursor is None
del cursor
for query in self.query.get_related_updates():
aux_rows = query.get_compiler(self.using).execute_sql(result_type)
if is_empty:
rows = aux_rows
is_empty = False
return rows
def pre_sql_setup(self):
"""
If the update depends on results from other tables, we need to do some
munging of the "where" conditions to match the format required for
(portable) SQL updates. That is done here.
Further, if we are going to be running multiple updates, we pull out
the id values to update at this point so that they don't change as a
result of the progressive updates.
"""
self.query.select_related = False
self.query.clear_ordering(True)
super(SQLUpdateCompiler, self).pre_sql_setup()
count = self.query.count_active_tables()
if not self.query.related_updates and count == 1:
return
# We need to use a sub-select in the where clause to filter on things
# from other tables.
query = self.query.clone(klass=Query)
query.bump_prefix()
query.extra = {}
query.select = []
query.add_fields([query.get_meta().pk.name])
# Recheck the count - it is possible that fiddling with the select
# fields above removes tables from the query. Refs #18304.
count = query.count_active_tables()
if not self.query.related_updates and count == 1:
return
must_pre_select = count > 1 and not self.connection.features.update_can_self_select
# Now we adjust the current query: reset the where clause and get rid
# of all the tables we don't need (since they're in the sub-select).
self.query.where = self.query.where_class()
if self.query.related_updates or must_pre_select:
# Either we're using the idents in multiple update queries (so
# don't want them to change), or the db backend doesn't support
# selecting from the updating table (e.g. MySQL).
idents = []
for rows in query.get_compiler(self.using).execute_sql(MULTI):
idents.extend([r[0] for r in rows])
self.query.add_filter(('pk__in', idents))
self.query.related_ids = idents
else:
# The fast path. Filters and updates in one query.
self.query.add_filter(('pk__in', query))
for alias in self.query.tables[1:]:
self.query.alias_refcount[alias] = 0
class SQLAggregateCompiler(SQLCompiler):
def as_sql(self, qn=None):
"""
Creates the SQL for this query. Returns the SQL string and list of
parameters.
"""
if qn is None:
qn = self.quote_name_unless_alias
sql, params = [], []
for aggregate in self.query.aggregate_select.values():
agg_sql, agg_params = aggregate.as_sql(qn, self.connection)
sql.append(agg_sql)
params.extend(agg_params)
sql = ', '.join(sql)
params = tuple(params)
sql = 'SELECT %s FROM (%s) subquery' % (sql, self.query.subquery)
params = params + self.query.sub_params
return sql, params
class SQLDateCompiler(SQLCompiler):
def results_iter(self):
"""
Returns an iterator over the results from executing this query.
"""
resolve_columns = hasattr(self, 'resolve_columns')
if resolve_columns:
from django.db.models.fields import DateField
fields = [DateField()]
else:
from django.db.backends.util import typecast_date
needs_string_cast = self.connection.features.needs_datetime_string_cast
offset = len(self.query.extra_select)
for rows in self.execute_sql(MULTI):
for row in rows:
date = row[offset]
if resolve_columns:
date = self.resolve_columns(row, fields)[offset]
elif needs_string_cast:
date = typecast_date(str(date))
if isinstance(date, datetime.datetime):
date = date.date()
yield date
class SQLDateTimeCompiler(SQLCompiler):
def results_iter(self):
"""
Returns an iterator over the results from executing this query.
"""
resolve_columns = hasattr(self, 'resolve_columns')
if resolve_columns:
from django.db.models.fields import DateTimeField
fields = [DateTimeField()]
else:
from django.db.backends.util import typecast_timestamp
needs_string_cast = self.connection.features.needs_datetime_string_cast
offset = len(self.query.extra_select)
for rows in self.execute_sql(MULTI):
for row in rows:
datetime = row[offset]
if resolve_columns:
datetime = self.resolve_columns(row, fields)[offset]
elif needs_string_cast:
datetime = typecast_timestamp(str(datetime))
# Datetimes are artifically returned in UTC on databases that
# don't support time zone. Restore the zone used in the query.
if settings.USE_TZ:
if datetime is None:
raise ValueError("Database returned an invalid value "
"in QuerySet.datetimes(). Are time zone "
"definitions for your database and pytz installed?")
datetime = datetime.replace(tzinfo=None)
datetime = timezone.make_aware(datetime, self.query.tzinfo)
yield datetime
def order_modified_iter(cursor, trim, sentinel):
"""
Yields blocks of rows from a cursor. We use this iterator in the special
case when extra output columns have been added to support ordering
requirements. We must trim those extra columns before anything else can use
the results, since they're only needed to make the SQL valid.
"""
for rows in iter((lambda: cursor.fetchmany(GET_ITERATOR_CHUNK_SIZE)),
sentinel):
yield [r[:-trim] for r in rows]
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