210 lines
7.8 KiB
Python
210 lines
7.8 KiB
Python
"""
|
|
Query subclasses which provide extra functionality beyond simple data retrieval.
|
|
"""
|
|
|
|
from django.core.exceptions import FieldError
|
|
from django.db import connections
|
|
from django.db.models.query_utils import Q
|
|
from django.db.models.sql.constants import (
|
|
CURSOR, GET_ITERATOR_CHUNK_SIZE, NO_RESULTS,
|
|
)
|
|
from django.db.models.sql.query import Query
|
|
from django.utils import six
|
|
|
|
__all__ = ['DeleteQuery', 'UpdateQuery', 'InsertQuery', 'AggregateQuery']
|
|
|
|
|
|
class DeleteQuery(Query):
|
|
"""
|
|
Delete queries are done through this class, since they are more constrained
|
|
than general queries.
|
|
"""
|
|
|
|
compiler = 'SQLDeleteCompiler'
|
|
|
|
def do_query(self, table, where, using):
|
|
self.tables = [table]
|
|
self.where = where
|
|
cursor = self.get_compiler(using).execute_sql(CURSOR)
|
|
return cursor.rowcount if cursor else 0
|
|
|
|
def delete_batch(self, pk_list, using):
|
|
"""
|
|
Set up and execute delete queries for all the objects in pk_list.
|
|
|
|
More than one physical query may be executed if there are a
|
|
lot of values in pk_list.
|
|
"""
|
|
# number of objects deleted
|
|
num_deleted = 0
|
|
field = self.get_meta().pk
|
|
for offset in range(0, len(pk_list), GET_ITERATOR_CHUNK_SIZE):
|
|
self.where = self.where_class()
|
|
self.add_q(Q(
|
|
**{field.attname + '__in': pk_list[offset:offset + GET_ITERATOR_CHUNK_SIZE]}))
|
|
num_deleted += self.do_query(self.get_meta().db_table, self.where, using=using)
|
|
return num_deleted
|
|
|
|
def delete_qs(self, query, using):
|
|
"""
|
|
Delete the queryset in one SQL query (if possible). For simple queries
|
|
this is done by copying the query.query.where to self.query, for
|
|
complex queries by using subquery.
|
|
"""
|
|
innerq = query.query
|
|
# Make sure the inner query has at least one table in use.
|
|
innerq.get_initial_alias()
|
|
# The same for our new query.
|
|
self.get_initial_alias()
|
|
innerq_used_tables = [t for t in innerq.tables
|
|
if innerq.alias_refcount[t]]
|
|
if not innerq_used_tables or innerq_used_tables == self.tables:
|
|
# There is only the base table in use in the query.
|
|
self.where = innerq.where
|
|
else:
|
|
pk = query.model._meta.pk
|
|
if not connections[using].features.update_can_self_select:
|
|
# We can't do the delete using subquery.
|
|
values = list(query.values_list('pk', flat=True))
|
|
if not values:
|
|
return 0
|
|
return self.delete_batch(values, using)
|
|
else:
|
|
innerq.clear_select_clause()
|
|
innerq.select = [
|
|
pk.get_col(self.get_initial_alias())
|
|
]
|
|
values = innerq
|
|
self.where = self.where_class()
|
|
self.add_q(Q(pk__in=values))
|
|
cursor = self.get_compiler(using).execute_sql(CURSOR)
|
|
return cursor.rowcount if cursor else 0
|
|
|
|
|
|
class UpdateQuery(Query):
|
|
"""
|
|
Represents an "update" SQL query.
|
|
"""
|
|
|
|
compiler = 'SQLUpdateCompiler'
|
|
|
|
def __init__(self, *args, **kwargs):
|
|
super(UpdateQuery, self).__init__(*args, **kwargs)
|
|
self._setup_query()
|
|
|
|
def _setup_query(self):
|
|
"""
|
|
Runs on initialization and after cloning. Any attributes that would
|
|
normally be set in __init__ should go in here, instead, so that they
|
|
are also set up after a clone() call.
|
|
"""
|
|
self.values = []
|
|
self.related_ids = None
|
|
if not hasattr(self, 'related_updates'):
|
|
self.related_updates = {}
|
|
|
|
def clone(self, klass=None, **kwargs):
|
|
return super(UpdateQuery, self).clone(klass, related_updates=self.related_updates.copy(), **kwargs)
|
|
|
|
def update_batch(self, pk_list, values, using):
|
|
self.add_update_values(values)
|
|
for offset in range(0, len(pk_list), GET_ITERATOR_CHUNK_SIZE):
|
|
self.where = self.where_class()
|
|
self.add_q(Q(pk__in=pk_list[offset: offset + GET_ITERATOR_CHUNK_SIZE]))
|
|
self.get_compiler(using).execute_sql(NO_RESULTS)
|
|
|
|
def add_update_values(self, values):
|
|
"""
|
|
Convert a dictionary of field name to value mappings into an update
|
|
query. This is the entry point for the public update() method on
|
|
querysets.
|
|
"""
|
|
values_seq = []
|
|
for name, val in six.iteritems(values):
|
|
field = self.get_meta().get_field(name)
|
|
direct = not (field.auto_created and not field.concrete) or not field.concrete
|
|
model = field.model._meta.concrete_model
|
|
if not direct or (field.is_relation and field.many_to_many):
|
|
raise FieldError(
|
|
'Cannot update model field %r (only non-relations and '
|
|
'foreign keys permitted).' % field
|
|
)
|
|
if model is not self.get_meta().model:
|
|
self.add_related_update(model, field, val)
|
|
continue
|
|
values_seq.append((field, model, val))
|
|
return self.add_update_fields(values_seq)
|
|
|
|
def add_update_fields(self, values_seq):
|
|
"""
|
|
Append a sequence of (field, model, value) triples to the internal list
|
|
that will be used to generate the UPDATE query. Might be more usefully
|
|
called add_update_targets() to hint at the extra information here.
|
|
"""
|
|
for field, model, val in values_seq:
|
|
if hasattr(val, 'resolve_expression'):
|
|
# Resolve expressions here so that annotations are no longer needed
|
|
val = val.resolve_expression(self, allow_joins=False, for_save=True)
|
|
self.values.append((field, model, val))
|
|
|
|
def add_related_update(self, model, field, value):
|
|
"""
|
|
Adds (name, value) to an update query for an ancestor model.
|
|
|
|
Updates are coalesced so that we only run one update query per ancestor.
|
|
"""
|
|
self.related_updates.setdefault(model, []).append((field, None, value))
|
|
|
|
def get_related_updates(self):
|
|
"""
|
|
Returns a list of query objects: one for each update required to an
|
|
ancestor model. Each query will have the same filtering conditions as
|
|
the current query but will only update a single table.
|
|
"""
|
|
if not self.related_updates:
|
|
return []
|
|
result = []
|
|
for model, values in six.iteritems(self.related_updates):
|
|
query = UpdateQuery(model)
|
|
query.values = values
|
|
if self.related_ids is not None:
|
|
query.add_filter(('pk__in', self.related_ids))
|
|
result.append(query)
|
|
return result
|
|
|
|
|
|
class InsertQuery(Query):
|
|
compiler = 'SQLInsertCompiler'
|
|
|
|
def __init__(self, *args, **kwargs):
|
|
super(InsertQuery, self).__init__(*args, **kwargs)
|
|
self.fields = []
|
|
self.objs = []
|
|
|
|
def insert_values(self, fields, objs, raw=False):
|
|
"""
|
|
Set up the insert query from the 'insert_values' dictionary. The
|
|
dictionary gives the model field names and their target values.
|
|
|
|
If 'raw_values' is True, the values in the 'insert_values' dictionary
|
|
are inserted directly into the query, rather than passed as SQL
|
|
parameters. This provides a way to insert NULL and DEFAULT keywords
|
|
into the query, for example.
|
|
"""
|
|
self.fields = fields
|
|
self.objs = objs
|
|
self.raw = raw
|
|
|
|
|
|
class AggregateQuery(Query):
|
|
"""
|
|
An AggregateQuery takes another query as a parameter to the FROM
|
|
clause and only selects the elements in the provided list.
|
|
"""
|
|
|
|
compiler = 'SQLAggregateCompiler'
|
|
|
|
def add_subquery(self, query, using):
|
|
query.subquery = True
|
|
self.subquery, self.sub_params = query.get_compiler(using).as_sql(with_col_aliases=True)
|