Hello, group! I am still dealing with the relationship I asked before (http://groups.google.com/group/sqlalchemy/browse_thread/thread/c1d46daf35116999).
To tell the truth, I'm not even sure if this is a question I should ask in the SqlAlchemy forum because I'm also dealing with Megrok.rdb (http://pypi.python.org/pypi/megrok.rdb) and I don't know if that's what is causing the problem, but I'm pretty lost... As I explained in my other question, I think the rdb.Model thing that appears in the classes is just a tool to create the mapper "class <--> table" in a slightly more transparent way for the programmer. That's why I thought I may get some help here. In this message, I have simplified the code (compared to my former question) to make it clearer, but well... The fact is that now I'm getting a problem with a simple 1:1 relationship (if I can fix it, I will be able to move to the more complicated stuff as I detailed in the former question) I am getting this error: Foreign key assocated with column 'children_table.id' could not find table 'parents_table' with which to generate a foreign key to target column 'id' I have a file, called Tables.py where all the classes and auxiliary (or intermediate) tables that I'm going to use in my application are defined: Tables.py >> class Parent(rdb.Model): rdb.metadata(metadata) rdb.tablename("parents_table") id = Column("id", Integer, primary_key=True) _whateverField= Column("whatever_field", String(16)) #Irrelevant child1 = relationship("Child", uselist=False) class Child(rdb.Model): rdb.metadata(metadata) rdb.tablename("children_table") id = Column("id", Integer, ForeignKey(Parent.id), primary_key = True) type = Column("type", String(2)) #Irrelevant (for this example) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - And then I have two different Python .py files (Parent.py and Child.py) where the methods that manage said classes are implemented. In those files, the static area of each class is copied from Tables.py with some changes in the quotes (where I can use the object itself, I use it): Parent.py >> from child import Child metadata = rdb.MetaData() class Parent(rdb.Model): rdb.metadata(metadata) rdb.tablename("parents_table") id = Column("id", Integer, primary_key=True) _whateverField= Column("whatever_field", String(16)) #Irrelevant child1 = relationship(Child, uselist=False) #No quotation marks on this Child - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - And Child.py > > metadata = rdb.MetaData() class Child(rdb.Model): rdb.metadata(metadata) rdb.tablename("children_table") id = Column("id", Integer, ForeignKey("parent_table.id"), primary_key = True) type = Column("type", String(2)) #Irrelevant (for this example) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - When I try to use these classes, I get: Foreign key assocated with column 'children_table.id' could not find table 'parents_table' with which to generate a foreign key to target column 'id' But if I take a look to the tables with a MySQL Query Browser, the table "parents_table" is there, happily and properly created. In some other places, I have had similar problems, but I've been able to fix them by delaying the imports. I had been able to (kind of) import the Parent type in the Child file so I can use the Parent object directly. It would be a little bit as if in this case I was able to do: from parent import Parent [ . . . ] class Child(rdb.Model): [ . . . ] id = Column("id", Integer, ForeignKey(Parent.id), primary_key = True) and that usually fixed the problem but in this specific case, I can't really do that: In the Parent file I need to import the Child and that gives a very, very nasty circular dependency problem. Is there a way to tell the Child.py file something like "Hey, dude... Here's the parent_table that you need!" ? (Well... In a more Pythonic way, of course... I don't think 'dude'is a reserved keywork in Python, or an SqlAlchemy type). I don't know, something like: from whatever.repository.of.tables import parent_table so I can, without quotes, use: id = Column("id", Integer, ForeignKey(parent_table.id), primary_key = True) (I guess that may work) Thank you all. -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalch...@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.
