diff options
Diffstat (limited to 'django/db/models/sql/query.py')
| -rw-r--r-- | django/db/models/sql/query.py | 43 |
1 files changed, 33 insertions, 10 deletions
diff --git a/django/db/models/sql/query.py b/django/db/models/sql/query.py index 1c22593293..2dba2bdb3c 100644 --- a/django/db/models/sql/query.py +++ b/django/db/models/sql/query.py @@ -52,6 +52,7 @@ class Query(object): self.default_cols = True self.default_ordering = True self.standard_ordering = True + self.ordering_aliases = [] self.start_meta = None # SQL-related attributes @@ -139,6 +140,7 @@ class Query(object): obj.default_cols = self.default_cols obj.default_ordering = self.default_ordering obj.standard_ordering = self.standard_ordering + obj.ordering_aliases = [] obj.start_meta = self.start_meta obj.select = self.select[:] obj.tables = self.tables[:] @@ -215,16 +217,18 @@ class Query(object): self.pre_sql_setup() out_cols = self.get_columns() ordering = self.get_ordering() + # This must come after 'select' and 'ordering' -- see docstring of # get_from_clause() for details. from_, f_params = self.get_from_clause() + where, w_params = self.where.as_sql(qn=self.quote_name_unless_alias) params = list(self.extra_select_params) result = ['SELECT'] if self.distinct: result.append('DISTINCT') - result.append(', '.join(out_cols)) + result.append(', '.join(out_cols + self.ordering_aliases)) result.append('FROM') result.extend(from_) @@ -465,15 +469,13 @@ class Query(object): def get_ordering(self): """ - Returns a tuple representing the SQL elements in the "order by" clause. + Returns list representing the SQL elements in the "order by" clause. + 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(). """ - # FIXME: It's an SQL-92 requirement that all ordering columns appear as - # output columns in the query (in the select statement) or be ordinals. - # We don't enforce that here, but we should (by adding to the select - # columns), for portability. if self.extra_order_by: ordering = self.extra_order_by elif not self.default_ordering: @@ -485,6 +487,7 @@ class Query(object): distinct = self.distinct select_aliases = self._select_aliases result = [] + ordering_aliases = [] if self.standard_ordering: asc, desc = ORDER_DIR['ASC'] else: @@ -515,13 +518,16 @@ class Query(object): for table, col, order in self.find_ordering_name(field, self.model._meta, default_order=asc): elt = '%s.%s' % (qn(table), qn2(col)) - if not distinct or elt in select_aliases: - result.append('%s %s' % (elt, order)) + if distinct and elt not in select_aliases: + ordering_aliases.append(elt) + result.append('%s %s' % (elt, order)) else: col, order = get_order_dir(field, asc) elt = qn(col) - if not distinct or elt in select_aliases: - result.append('%s %s' % (elt, order)) + if distinct and elt not in select_aliases: + ordering_aliases.append(elt) + result.append('%s %s' % (elt, order)) + self.ordering_aliases = ordering_aliases return result def find_ordering_name(self, name, opts, alias=None, default_order='ASC', @@ -1379,8 +1385,14 @@ class Query(object): if not result_type: return cursor if result_type == SINGLE: + if self.ordering_aliases: + return cursor.fetchone()[:-len(results.ordering_aliases)] return cursor.fetchone() + # The MULTI case. + if self.ordering_aliases: + return order_modified_iter(cursor, len(self.ordering_aliases), + self.connection.features.empty_fetchmany_value) return iter((lambda: cursor.fetchmany(GET_ITERATOR_CHUNK_SIZE)), self.connection.features.empty_fetchmany_value) @@ -1408,6 +1420,17 @@ def empty_iter(): """ yield iter([]).next() +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] + def setup_join_cache(sender): """ The information needed to join between model fields is something that is |