3 files changed, 11 insertions, 5 deletions
diff --git a/lib/sqlalchemy/sql/compiler.py b/lib/sqlalchemy/sql/compiler.py
index 095c84f03..85d5ff6da 100644
--- a/lib/sqlalchemy/sql/compiler.py
+++ b/lib/sqlalchemy/sql/compiler.py
@@ -215,7 +215,10 @@ class Compiled(object):
         pass
 
     def _execute_on_connection(self, connection, multiparams, params):
-        return connection._execute_compiled(self, multiparams, params)
+        if self.can_execute:
+            return connection._execute_compiled(self, multiparams, params)
+        else:
+            raise exc.ObjectNotExecutableError(self.statement)
 
     @property
     def sql_compiler(self):
diff --git a/lib/sqlalchemy/sql/elements.py b/lib/sqlalchemy/sql/elements.py
index e277b28a4..75d5368d5 100644
--- a/lib/sqlalchemy/sql/elements.py
+++ b/lib/sqlalchemy/sql/elements.py
@@ -259,7 +259,10 @@ class ClauseElement(Visitable):
             return self
 
     def _execute_on_connection(self, connection, multiparams, params):
-        return connection._execute_clauseelement(self, multiparams, params)
+        if self.supports_execution:
+            return connection._execute_clauseelement(self, multiparams, params)
+        else:
+            raise exc.ObjectNotExecutableError(self)
 
     def unique_params(self, *optionaldict, **kwargs):
         """Return a copy with :func:`bindparam()` elements replaced.
diff --git a/lib/sqlalchemy/sql/schema.py b/lib/sqlalchemy/sql/schema.py
index e364b2e7f..98a96fd56 100644
--- a/lib/sqlalchemy/sql/schema.py
+++ b/lib/sqlalchemy/sql/schema.py
@@ -71,9 +71,6 @@ class SchemaItem(SchemaEventTarget, visitors.Visitable):
 
     __visit_name__ = 'schema_item'
 
-    def _execute_on_connection(self, connection, multiparams, params):
-        return connection._execute_default(self, multiparams, params)
-
     def _init_items(self, *args):
         """Initialize the list of child items for this SchemaItem."""
 
@@ -1941,6 +1938,9 @@ class DefaultGenerator(_NotAColumnExpr, SchemaItem):
             bind = _bind_or_error(self)
         return bind._execute_default(self, **kwargs)
 
+    def _execute_on_connection(self, connection, multiparams, params):
+        return connection._execute_default(self, multiparams, params)
+
     @property
     def bind(self):
         """Return the connectable associated with this default."""