Hello, if I understand your description correctly you include your declarative_base model classes into your migration scripts. You should not do this.
You can reference existing tables in migration scripts via schema reflection but using declarative_base gets a bit more complicated. Maybe you get some more ideas from the migrate-users group (added to discussion). Regards Jan Dittberner 2011/6/4 Ryu Ishimoto <r...@midokura.jp>: > Hi, I just recently started looking into using sqlalchemy migration, > and I'm having difficulty understanding how it works with > declarative_base. The problem is I don't quite understand how > migration COULD handle the situation in which the model class > definition changes in certain scenarios. > > For example, let's say if we have: > > '001_create_users_table' that creates users table. > '002_create_addresses_table' that creates addresses table, and adds > 'address_id' column in the users table which is a foreign key > reference to the addresses table. > > When creating 002_create_addresses_table, using declarative_base, you > would have to also modify the class definitions to include Address > class and address_id attribute in User class referring to the Address > class. > > But then what happens if a user wants to run these migration scripts > to build the database from scratch? 001_create_users_table would look > at the User class and finds that there is 'address_id' column > referring to Address table that hasn't even been created in the > database yet. > > Is this a case that sqlalchemy migrate just cannot handle? Do I need > to not use declarative_base and define Tables in the migration? I am > new to sqlalchemy, so perhaps I'm missing something fundamental. > > Thanks in advance! > > Ryu -- Jan Dittberner Software Architect - Debian Developer -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalchemy@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
