diff -r 57b4279d8c4e -r 03e267d67478 app/django/db/models/sql/subqueries.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/app/django/db/models/sql/subqueries.py	Fri Jul 18 18:22:23 2008 +0000
@@ -0,0 +1,385 @@
+"""
+Query subclasses which provide extra functionality beyond simple data retrieval.
+"""
+
+from django.contrib.contenttypes import generic
+from django.core.exceptions import FieldError
+from django.db.models.sql.constants import *
+from django.db.models.sql.datastructures import RawValue, Date
+from django.db.models.sql.query import Query
+from django.db.models.sql.where import AND
+
+__all__ = ['DeleteQuery', 'UpdateQuery', 'InsertQuery', 'DateQuery',
+        'CountQuery']
+
+class DeleteQuery(Query):
+    """
+    Delete queries are done through this class, since they are more constrained
+    than general queries.
+    """
+    def as_sql(self):
+        """
+        Creates the SQL for this query. Returns the SQL string and list of
+        parameters.
+        """
+        assert len(self.tables) == 1, \
+                "Can only delete from one table at a time."
+        result = ['DELETE FROM %s' % self.quote_name_unless_alias(self.tables[0])]
+        where, params = self.where.as_sql()
+        result.append('WHERE %s' % where)
+        return ' '.join(result), tuple(params)
+
+    def do_query(self, table, where):
+        self.tables = [table]
+        self.where = where
+        self.execute_sql(None)
+
+    def delete_batch_related(self, pk_list):
+        """
+        Set up and execute delete queries for all the objects related to the
+        primary key values in pk_list. To delete the objects themselves, use
+        the delete_batch() method.
+
+        More than one physical query may be executed if there are a
+        lot of values in pk_list.
+        """
+        cls = self.model
+        for related in cls._meta.get_all_related_many_to_many_objects():
+            if not isinstance(related.field, generic.GenericRelation):
+                for offset in range(0, len(pk_list), GET_ITERATOR_CHUNK_SIZE):
+                    where = self.where_class()
+                    where.add((None, related.field.m2m_reverse_name(),
+                            related.field, 'in',
+                            pk_list[offset : offset+GET_ITERATOR_CHUNK_SIZE]),
+                            AND)
+                    self.do_query(related.field.m2m_db_table(), where)
+
+        for f in cls._meta.many_to_many:
+            w1 = self.where_class()
+            if isinstance(f, generic.GenericRelation):
+                from django.contrib.contenttypes.models import ContentType
+                field = f.rel.to._meta.get_field(f.content_type_field_name)
+                w1.add((None, field.column, field, 'exact',
+                        ContentType.objects.get_for_model(cls).id), AND)
+            for offset in range(0, len(pk_list), GET_ITERATOR_CHUNK_SIZE):
+                where = self.where_class()
+                where.add((None, f.m2m_column_name(), f, 'in',
+                        pk_list[offset : offset + GET_ITERATOR_CHUNK_SIZE]),
+                        AND)
+                if w1:
+                    where.add(w1, AND)
+                self.do_query(f.m2m_db_table(), where)
+
+    def delete_batch(self, pk_list):
+        """
+        Set up and execute delete queries for all the objects in pk_list. This
+        should be called after delete_batch_related(), if necessary.
+
+        More than one physical query may be executed if there are a
+        lot of values in pk_list.
+        """
+        for offset in range(0, len(pk_list), GET_ITERATOR_CHUNK_SIZE):
+            where = self.where_class()
+            field = self.model._meta.pk
+            where.add((None, field.column, field, 'in',
+                    pk_list[offset : offset + GET_ITERATOR_CHUNK_SIZE]), AND)
+            self.do_query(self.model._meta.db_table, where)
+
+class UpdateQuery(Query):
+    """
+    Represents an "update" SQL query.
+    """
+    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 execute_sql(self, result_type=None):
+        super(UpdateQuery, self).execute_sql(result_type)
+        for query in self.get_related_updates():
+            query.execute_sql(result_type)
+
+    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.values:
+            return '', ()
+        table = self.tables[0]
+        qn = self.quote_name_unless_alias
+        result = ['UPDATE %s' % qn(table)]
+        result.append('SET')
+        values, update_params = [], []
+        for name, val, placeholder in self.values:
+            if val is not None:
+                values.append('%s = %s' % (qn(name), placeholder))
+                update_params.append(val)
+            else:
+                values.append('%s = NULL' % qn(name))
+        result.append(', '.join(values))
+        where, params = self.where.as_sql()
+        if where:
+            result.append('WHERE %s' % where)
+        return ' '.join(result), tuple(update_params + params)
+
+    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.select_related = False
+        self.clear_ordering(True)
+        super(UpdateQuery, self).pre_sql_setup()
+        count = self.count_active_tables()
+        if not self.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.clone(klass=Query)
+        query.bump_prefix()
+        query.extra_select = {}
+        first_table = query.tables[0]
+        if query.alias_refcount[first_table] == 1:
+            # We can remove one table from the inner query.
+            query.unref_alias(first_table)
+            for i in xrange(1, len(query.tables)):
+                table = query.tables[i]
+                if query.alias_refcount[table]:
+                    break
+            join_info = query.alias_map[table]
+            query.select = [(join_info[RHS_ALIAS], join_info[RHS_JOIN_COL])]
+            must_pre_select = False
+        else:
+            query.select = []
+            query.add_fields([query.model._meta.pk.name])
+            must_pre_select = 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.where = self.where_class()
+        if self.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.execute_sql(MULTI):
+                idents.extend([r[0] for r in rows])
+            self.add_filter(('pk__in', idents))
+            self.related_ids = idents
+        else:
+            # The fast path. Filters and updates in one query.
+            self.add_filter(('pk__in', query))
+        for alias in self.tables[1:]:
+            self.alias_refcount[alias] = 0
+
+    def clear_related(self, related_field, pk_list):
+        """
+        Set up and execute an update query that clears related entries for the
+        keys in pk_list.
+
+        This is used by the QuerySet.delete_objects() method.
+        """
+        for offset in range(0, len(pk_list), GET_ITERATOR_CHUNK_SIZE):
+            self.where = self.where_class()
+            f = self.model._meta.pk
+            self.where.add((None, f.column, f, 'in',
+                    pk_list[offset : offset + GET_ITERATOR_CHUNK_SIZE]),
+                    AND)
+            self.values = [(related_field.column, None, '%s')]
+            self.execute_sql(None)
+
+    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 values.iteritems():
+            field, model, direct, m2m = self.model._meta.get_field_by_name(name)
+            if not direct or m2m:
+                raise FieldError('Cannot update model field %r (only non-relations and foreign keys permitted).' % field)
+            values_seq.append((field, model, val))
+        return self.add_update_fields(values_seq)
+
+    def add_update_fields(self, values_seq):
+        """
+        Turn a sequence of (field, model, value) triples into an update query.
+        Used by add_update_values() as well as the "fast" update path when
+        saving models.
+        """
+        from django.db.models.base import Model
+        for field, model, val in values_seq:
+            # FIXME: Some sort of db_prep_* is probably more appropriate here.
+            if field.rel and isinstance(val, Model):
+                val = val.pk
+
+            # Getting the placeholder for the field.
+            if hasattr(field, 'get_placeholder'):
+                placeholder = field.get_placeholder(val)
+            else:
+                placeholder = '%s'
+
+            if model:
+                self.add_related_update(model, field.column, val, placeholder)
+            else:
+                self.values.append((field.column, val, placeholder))
+
+    def add_related_update(self, model, column, value, placeholder):
+        """
+        Adds (name, value) to an update query for an ancestor model.
+
+        Updates are coalesced so that we only run one update query per ancestor.
+        """
+        try:
+            self.related_updates[model].append((column, value, placeholder))
+        except KeyError:
+            self.related_updates[model] = [(column, value, placeholder)]
+
+    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 self.related_updates.iteritems():
+            query = UpdateQuery(model, self.connection)
+            query.values = values
+            if self.related_ids:
+                query.add_filter(('pk__in', self.related_ids))
+            result.append(query)
+        return result
+
+class InsertQuery(Query):
+    def __init__(self, *args, **kwargs):
+        super(InsertQuery, self).__init__(*args, **kwargs)
+        self.columns = []
+        self.values = []
+        self.params = ()
+
+    def clone(self, klass=None, **kwargs):
+        extras = {'columns': self.columns[:], 'values': self.values[:],
+                'params': self.params}
+        return super(InsertQuery, self).clone(klass, extras)
+
+    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
+        result = ['INSERT INTO %s' % qn(self.model._meta.db_table)]
+        result.append('(%s)' % ', '.join([qn(c) for c in self.columns]))
+        result.append('VALUES (%s)' % ', '.join(self.values))
+        return ' '.join(result), self.params
+
+    def execute_sql(self, return_id=False):
+        cursor = super(InsertQuery, self).execute_sql(None)
+        if return_id:
+            return self.connection.ops.last_insert_id(cursor,
+                    self.model._meta.db_table, self.model._meta.pk.column)
+
+    def insert_values(self, insert_values, raw_values=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.
+        """
+        placeholders, values = [], []
+        for field, val in insert_values:
+            if hasattr(field, 'get_placeholder'):
+                # Some fields (e.g. geo fields) need special munging before
+                # they can be inserted.
+                placeholders.append(field.get_placeholder(val))
+            else:
+                placeholders.append('%s')
+
+            self.columns.append(field.column)
+            values.append(val)
+        if raw_values:
+            self.values.extend(values)
+        else:
+            self.params += tuple(values)
+            self.values.extend(placeholders)
+
+class DateQuery(Query):
+    """
+    A DateQuery is a normal query, except that it specifically selects a single
+    date field. This requires some special handling when converting the results
+    back to Python objects, so we put it in a separate class.
+    """
+    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.extra_select)
+        for rows in self.execute_sql(MULTI):
+            for row in rows:
+                date = row[offset]
+                if resolve_columns:
+                    date = self.resolve_columns([date], fields)[0]
+                elif needs_string_cast:
+                    date = typecast_timestamp(str(date))
+                yield date
+
+    def add_date_select(self, column, lookup_type, order='ASC'):
+        """
+        Converts the query into a date extraction query.
+        """
+        alias = self.join((None, self.model._meta.db_table, None, None))
+        select = Date((alias, column), lookup_type,
+                self.connection.ops.date_trunc_sql)
+        self.select = [select]
+        self.select_fields = [None]
+        self.select_related = False # See #7097.
+        self.distinct = True
+        self.order_by = order == 'ASC' and [1] or [-1]
+
+class CountQuery(Query):
+    """
+    A CountQuery knows how to take a normal query which would select over
+    multiple distinct columns and turn it into SQL that can be used on a
+    variety of backends (it requires a select in the FROM clause).
+    """
+    def get_from_clause(self):
+        result, params = self._query.as_sql()
+        return ['(%s) A1' % result], params
+
+    def get_ordering(self):
+        return ()
+