On May 1, 2013, at 12:58 PM, Michael Nachtigal <[email protected]> wrote:
> Hello, everyone, > > I have an existing database, and I'm trying to use reflection to populate my > metadata from an existing DB, but then define a declarative class (based on > one of the tables in the db), but a class with custom "renamed" mapped > attributes. > See the code below for what I have now (which "works"), but is there a better > way to do what I'm trying to do using sqlalchemy? > > my_engine = create_engine(...) > my_metadata = MetaData(bind=my_engine) > Base = declarative_base(bind=my_engine, metadata=my_metadata) > my_metadata.reflect() > > class User(Base): > __tablename__ = 'user_table' > > # is there a way to access the User member variables here to rename them? > # I can't seem to access __table__ here to get at the mapped columns > > # at this point, the User class does have all of the necessary mapped field > names, but I want to rename them > User.name = User.user_name > User.location = User.address > # ... and so on ... > > Feel free to ask for clarification or correct my choice of words, and many > thanks in advance for your time and reply! I'm not sure how that works exactly because __tablename__ will cause it to produce a new Table object, attempting to replace the existing one in my_metadata, and you'll get an error. Specifying a declared class from an existing table should use __table__ (see http://docs.sqlalchemy.org/en/rel_0_8/orm/extensions/declarative.html#using-reflection-with-declarative). You can then map alternate names referring to that table object: user_table = my_metadata.tables['user_table'] class User(Base): __table__ = user_table name = user_table.c.user_name location = user_table.c.address -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sqlalchemy?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
