In sqlalchemy, I use classical mapping and autoload=True. I want to query data which is jsontype from postgresql.
D:\Python27\lib\site-packages\sqlalchemy\dialects\postgresql\base.py:1706: SAWarning: Did not recognize type 'json' of column 'comm_media_alias'name, format_type, default, notnull, domains, enums, schema)
how to deal with this problem
The JSON type in PostgreSQL is a relatively new data type in PostgreSQL, and thus SQLAlchemy has only recently added functionality to properly detect it. At the time of this question, SQLAlchemy would not be able to detect the "JSON" column type, as doing so relied on functionality that it did not yet support.
SQLAlchemy 0.9 was released on December 30th, 2013. This version contains support for the PostgreSQL JSON data type, so I would recommend upgrading to this version and trying again.
If you can't upgrade (or the upgrade still isn't working for you), you can also change your column type to something else (like TEXT).
Another thing to note about this is that it is not an error: it is a warning. I'm not sure what SQLAlchemy will actually try to do when it is working with the column that is a JSON type, but it might end up working anyway.
