Hi Simon, definitely multiple imports is the issue here, however I don't know how to get rid of it, let's say I have a module which i named "ormstuff" inside it I have a class named "mybase", I do have 2 other modules which are using this class, and to do so I import it in both places. Now this might just be me skipping the basics, however if I don't import the mybase in both modules I cannot use it, since it should throw an undefined variable exception.
2015-03-02 12:47 GMT+01:00 Simon King <si...@simonking.org.uk>: > On Mon, Mar 2, 2015 at 11:29 AM, Martino Io <martino8...@gmail.com> wrote: > > Hello, I've been busy writing an application which now has grown > > considerably, it spans across several packages/modules totalling 200K > lines > > of python code. > > Recently I made some changes to the structure and decided to split > several > > classes into separate modules for greater flexibility; the problem I'm > > facing now > > is quite strange, before I was using mainly 1 file for all the ORM > > definitions, but since I split that into several files, I've started to > get > > exceptions due to multiple > > Base objects being defined and no shared mapper to store the metadata. > I've > > changed approach and started to import the base from a single module, > > however given the high number of modules and cross imports I get > exceptions > > like: > > > > sqlalchemy.exc.InvalidRequestError: Table 'fabrics' is already defined > for > > this MetaData instance. Specify 'extend_existing=True' to redefine > options > > and columns on an existing Table object. > > > > I thought that by adding "use_existing" would fix the issue (the mapper > > will ignore further imports which redefine the objects) but instead got: > > > > InvalidRequestError: Multiple classes found for path "Group" in the > registry > > of this declarative base. Please use a fully module-qualified path. > > > > So going back to the question, if I have a cross dependant package (which > > imports classes which are ORM classes), how do I avoid the mapper > > "redefining" a class? > > Also any advice on best way to structure packages/modules in an ORM use > case > > would be appreciated. > > > > extend_existing is almost certainly not what you want here. Each > mapped class should only be defined in a single place. If you've done > that, and are still getting this error, it suggests that perhaps your > Python modules are being imported more than once. Try putting "print > 'importing module %s' % __name__" before your class definition. If you > see the output more than once, then the module is being imported > multiple times under different names. > > Hope that helps, > > Simon > > -- > You received this message because you are subscribed to a topic in the > Google Groups "sqlalchemy" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/sqlalchemy/gExzW1RNF7A/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > sqlalchemy+unsubscr...@googlegroups.com. > To post to this group, send email to sqlalchemy@googlegroups.com. > Visit this group at http://groups.google.com/group/sqlalchemy. > For more options, visit https://groups.google.com/d/optout. > -- 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 sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at http://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/d/optout.
