Ticket #214: get_values.patch

django/core/meta.py

@@ -562 +562 @@
         new_mod.get_iterator = curry(function_get_iterator, opts, new_class)
         new_mod.get_iterator.__doc__ = "Returns an iterator of %s objects matching the given parameters." % name
 
+        new_mod.get_values = curry(function_get_values_list, opts, new_class)
+        new_mod.get_values.__doc__ = "Returns a list of dicts matching the given parameters."
+
+        new_mod.get_values_iterator = curry(function_get_values_iterator, opts, new_class)
+        new_mod.get_values_iterator.__doc__ = "Returns an iterator of dicts matching the given parameters."
+
         new_mod.get_count = curry(function_get_count, opts)
         new_mod.get_count.__doc__ = "Returns the number of %s objects matching the given parameters." % name
 
@@ -1047 +1053 @@
             setattr(obj, f.rel.get_cache_name(), rel_obj)
     return obj, index_end
 
+def function_get_values_iterator(opts, klass, **kwargs):
+    """
+    Return SELECT results as a list of dicts rather than as objects.
+    Example use: "SELECT DISTINCT year, month FROM blog ORDER BY year, month"
+    """
+    # kwargs['select'] is a dictionary, and dictionaries' key order is
+    # undefined, so we convert it to a list of tuples internally.
+    kwargs['select'] = kwargs.get('select', {}).items()
+
+    cursor = db.db.cursor()
+    _, sql, params = function_get_sql_clause(opts, **kwargs)
+    # Allow user to specify a specific list of fields to fetch
+    fields = kwargs.get('fields')
+    if isinstance(fields, basestring):
+        # Be forgiving of mistakes: convert to tuple
+        fields = (fields,)
+    if not fields:
+        # Default to all fields
+        fields = [f.name for f in opts.fields]
+    select = ['%s.%s' % (opts.db_table, f) for f in fields]
+    cursor.execute("SELECT " + (kwargs.get('distinct') and "DISTINCT " or "") + ",".join(select) + sql, params)
+    while 1:
+        rows = cursor.fetchmany(GET_ITERATOR_CHUNK_SIZE)
+        if not rows:
+            raise StopIteration
+        for row in rows:
+            yield dict(zip(fields, row))
+
+def function_get_values_list(opts, klass, **kwargs):
+    return list(function_get_values_iterator(opts, klass, **kwargs))
+
 def function_get_iterator(opts, klass, **kwargs):
     # kwargs['select'] is a dictionary, and dictionaries' key order is
     # undefined, so we convert it to a list of tuples internally.
@@ -1117 +1154 @@
     # table_count is used to ensure table aliases are unique.
     tables, join_where, where, params = [], [], [], []
     for kwarg, kwarg_value in kwarg_items:
-        if kwarg in ('order_by', 'limit', 'offset', 'select_related', 'distinct', 'select', 'tables', 'where', 'params'):
+        if kwarg in ('order_by', 'limit', 'offset', 'select_related', 'distinct', 'select', 'tables', 'where', 'params', 'fields'):
             continue
         if kwarg_value is None:
             continue