I'm getting the following error message running TurboGears 2.1.1 and
SQLAlchemy 0.7.2, using TurboGears' multiple database setup described
here: http://turbogears.org/2.1/docs/main/MultipleDatabases.html. Both
databases are SQLite3 databases; one is the main database for the
TurboGears app; the other is a Trac 0.11.4 database. Can you help me
figure out what I'm doing wrong?
InvalidRequestError: One or more mappers failed to initialize - can't
proceed with initialization of other mappers. Original exception was:
When initializing mapper Mapper|WorkDone|work_done, expression 'ticket'
failed to locate a name ("name 'ticket' is not defined"). If this is a
class name, consider adding this relationship() to the <class
'projects.model.main.WorkDone'> class after both dependent classes have
been defined.
In my *model/__init__.py*, I import the model objects in this order (the
traceback makes me think this is the right place to work--either I need
to change the import order here, or add the relation() after the final
import, but neither of these solutions have seemed to work):
from projects.model.trac import *ticket*
from projects.model.main import WorkDone
# To follow the error message's instructions, I tried adding a
relation() here, but it generated a further error; maybe I didn't get
the syntax right.
If I should add a relation immediately above, what is the right syntax?
But this also seems like a hack to add a relation() here; if I have to
add a relation() here, does that mean my current code has circular
dependencies?
Here's the rest of my relevant code (with important items in bold):
In *projects/model/trac.py*, I have the following (I haven't put any
relation() or backref in this table definition, because this file is
borrowed mostly unmodified from Trac's experimental SQLAlchemy model
object code, and I want to keep it that way):
# begin Tim's modification
from projects.model import metadata2
metadata = metadata2
# end Tim's modification
# Ticket system
*ticket* = Table('ticket', metadata,
Column('id', Integer, primary_key=True),
Column('type', Text),
Column('time', Integer, index=True),
Column('changetime', Integer),
Column('component', Text),
Column('severity', Text),
Column('priority', Text),
Column('owner', Text),
Column('reporter', Text),
Column('cc', Text),
Column('version', Text),
Column('milestone', Text),
Column('status', Text, index=True),
Column('resolution', Text),
Column('summary', Text),
Column('description', Text),
Column('keywords', Text))
In *projects/model/main.py*, I have:
class *WorkDone*(DeclarativeBase):
__tablename__ = 'work_done'
id = Column(Integer, primary_key=True)
ticket_id = Column('ticket_id', Integer, ForeignKey('*ticket*.id'))
# many-to-one
*ticket* = relation('*ticket*', primaryjoin=ticket_id == '*ticket*.id')
The traceback is generated by line 105 of my
*projects/controllers/root.py*, which reads:
for p in DBSession.query(model.*Project*):
*projects/model/main.py* contains:
class *Project*(DeclarativeBase):
id = Column(Integer, primary_key=True)
workDone = relation('*WorkDone*') # one-to-many
...and that same class contains several properties that reference the
WorkDone model object like this one does:
@property
def totalHours(self):
return sum([w.elapsed for w in self.*workDone*])
Thank you for any help you can offer!
Tim
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