SQLAlchemy: How to do Table Reflection and MySQL?

[Nick Sabalausky]

On Mon, 22 Oct 2012 14:35:23 -0700 (PDT)
darnold <darnold992000 at yahoo.com> wrote:
> 
> i'm not brave enough to dig too deeply into SQLAlchemy, but maybe this
> will help? :
> 
> http://kashififtikhar.blogspot.com/2010/07/using-sqlalchemy-reflection-with-pylons.html
> 
> that came up from googling "sqlalchemy table reflection tutorial".

Thanks, your view of Google seems to be far better tailored for Python
than mine is, that doesn't come up for me anywhere on the first five
pages of results for that query.

Unfortunately the info on that page doesn't seem to work for me:

----------------------------------
from sqlalchemy import *
from sqlalchemy.orm import sessionmaker

engine = create_engine(my connection string)
meta = MetaData()
meta.bind = engine
meta.reflect()

Session = sessionmaker(bind=engine)
session = Session()

res = session.query(user).filter(user.name=="bert").first()
print res.name
----------------------------------

That just gives me:

NameError: name 'user' is not defined

(And yes, the code given on that page to print out the table info
*does* indicate a table named 'user' was found.)

I also tried this which also fails:

res =
session.query(meta.tables["user"]).filter(meta.tables["user"].name=="bert").first()

sqlalchemy.exc.ArgumentError: filter() argument must be of type
sqlalchemy.sql.ClauseElement or string

The page you linked to appears to get around the matter by manually
setting up tables filled with the reflected info, but that seems to
defeat much of the point for me. I may as well just set up the tables
manually without the reflection, which is what I'll probably do.

Maybe I just misunderstood what was meant in the SQLAlchemy docs here?:

"but note that SA can also “import” whole sets of Table objects
automatically from an existing database (this process is called table
reflection)."  --
http://docs.sqlalchemy.org/en/rel_0_7/core/tutorial.html

It said that but then didn't say how and didn't link to any info on how.