- add a note that alter_column->postgresql_using is raw SQL,

fixes #408

Change-Id: Ia569191d43d49178f78a7bcef458b671f750583e

diff --git a/alembic/operations/ops.py b/alembic/operations/ops.py
index f892227c94ec61ebf4dffaf96c4ef3d38d973709..8957982c86381f058d00b296a0cb323aa1999c9e 100644 (file)
--- a/alembic/operations/ops.py
+++ b/alembic/operations/ops.py
@@ -1399,7 +1399,9 @@ class AlterColumnOp(AlterTableOp):
 
         :param postgresql_using: String argument which will indicate a
          SQL expression to render within the Postgresql-specific USING clause
-         within ALTER COLUMN.
+         within ALTER COLUMN.    This string is taken directly as raw SQL which
+         must explicitly include any necessary quoting or escaping of tokens
+         within the expression.
 
          .. versionadded:: 0.8.8