Paolo,
You said, " I cannot move the pictures table declaration because both off
them have references to each other (mutual reference?) "
Why would the tables have mutual references? What kind of relation would
cause that?
Here are the kinds of relations I know about.
One to many; put the reference to the table with one in the table with many.
db.define_table('dog', field('name'))
db define_table('flea', field('dog', db.dog), field('gender'))
Many to many: create a third table to embody the relationship; reference
both tables.
db.define_table('dog', field('name'))
db.define_table('human', field('name'))
db.define_table('dog_human', field('dog', db.dog), field('human', db.human))
One to one: put the reference in the table less likely to hold data.
db.define_table('human', field('name'))
db.define_table('doctor', field('human', db.human), field('specialty'))
On Thursday, June 14, 2012 8:41:45 AM UTC-4, Paolo wrote:
>
> Hi all,
> Actually
> In route the field photo_id references pictures and in pictures the
> field route_id references route.
>
> --
> Paolo
>
> Il 14.06.2012 09:56 Niphlod ha scritto:
> > don't know precisely how dal works, but if a table have a field
> > referenced in a table defined after that, wouldn't that cause a
> > problem ?
> >
> > i.e. db.define_table('route',
> > Field('photo_id', 'reference pictures', readable=False,
> > writable=False)
> > )
> > db.define_table('pictures',
> > Field('name'))
> >
> > does not work, where
> > db.define_table('pictures',
> > Field('name'))
> > db.define_table('route',
> > Field('photo_id', 'reference pictures', readable=False,
> > writable=False)
> > )
> >
> > instead works ?
> >
> > Not using web2py, for normal sql development, you have to create
> > "child" tables before declaring a "parent" with references to it.
>
>
