[SQLObject] Re: [TurboGears] How to create tables with cyclic references?

[Ian B. <ia...@co...>]

João Paulo Fernandes Farias wrote:
> Hi!
> 
> How do I create tables with cyclic references?
> 
> As an example, suppose we have two classes:
> 
> class A(SQLObject):
>     b = ForeignKey('B')
> 
> class B(SQLObject):
>     a = ForeignKey('A')
> 
> 
> /me using turbogears...
> 
> I issue a: turbogears-admin.py sql create
> 
> It gives me some erros because it tries to create table A but B does not
> exists, so it cannot be referenced.
> 
> My suggestion is: Create all tables and then issue all the "alter table
> add constraint" as necessary.

This is kind of hard.  Technically you can do it like:

class A(SQLObject):
    b = ForeignKey('B')

class B(SQLObject):
    pass

def create():
    B.createTable()
    A.createTable()
    B.sqlmeta.addColumn(ForeignKey(name='a', foreignKey='A'),
changeSchema=True)


However, this won't work with sqlobject-admin (and thus
turbogears-admin.py).