Fixed #14733: no longer "validate" .raw() queries.

Turns out that a lot more than just SELECT can return data, and this list is
very hard to define up front in a cross-database manner. So let's just assume
that anyone using raw() is at least halfway competant and can deal with
the error messages if they don't use a data-returning query.

Thanks to Christophe Pettus for the patch.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@15803 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/models/sql/query.py

@@ -31,7 +31,6 @@ class RawQuery(object):
     """
 
     def __init__(self, sql, using, params=None):
-        self.validate_sql(sql)
         self.params = params or ()
         self.sql = sql
         self.using = using
@@ -62,11 +61,6 @@ class RawQuery(object):
         return [converter(column_meta[0])
                 for column_meta in self.cursor.description]
 
-    def validate_sql(self, sql):
-        if not sql.lower().strip().startswith('select'):
-            raise InvalidQuery('Raw queries are limited to SELECT queries. Use '
-                               'connection.cursor directly for other types of queries.')
-
     def __iter__(self):
         # Always execute a new query for a new iterator.
         # This could be optimized with a cache at the expense of RAM.