For the time being you can use this syntax:
db=DAL()
db.define_table('a',Field('b','integer'))
for i in range(10):
db.a.insert(b=i)
def lazy(f):
def g(self,f=f):
import copy
self=copy.copy(self)
return lambda *a,**b: f(self,*a,**b)
return g
class Scale:
@lazy
def c(self,scale=1):
return self.a.b*scale
db.a.virtualfields.append(Scale())
for row in db(db.a).select():
print row.b, row.c(1), row.c(2), row.c(3)
On Aug 14, 10:57 am, Santiago Gilabert <[email protected]>
wrote:
> anyone?
>
> I found that someone else asked about the same issue 5 month ago but there
> are no comments about it.
>
> http://groups.google.com/group/web2py/browse_thread/thread/845e6cdef5...
>
> Thanks
> Santiago
>
> On Sat, Aug 13, 2011 at 7:07 PM, Santiago <[email protected]>wrote:
>
>
>
>
>
>
>
> > Hello,
>
> > I have the following definitions in db.py
>
> > class ElectionVirtualField(object):
> > ...
> > def is_presidential(self):
> > def lazy(self=self):
> > return self.election.category == 'P'
> > return lazy
> > ...
>
> > db.define_table('election',
> > ...
> > Field('category', length=1, label=T('Category')
> > ...
>
> > The problem I have is that when I add a bunch of elections in dict()
> > (key = election.id, value = election row) and then traverse the dict,
> > I get wrong values from is_presidential()
>
> > Example:
>
> > elections = dict()
> > for election in db(db.election).select():
> > elections[election.id] = election
>
> > for (k, v) in elections.items():
> > print k , ' ', v.category, ' ', v.is_presidential()
>
> > Output:
> > 81 D True
> > 79 P True
>
> > As you can see, it returns True for both, but for the first one, it
> > should return False.
>
> > If I change the code to reload the election from the database, the
> > output is different:
>
> > Example:
>
> > elections = dict()
> > for election in db(db.election).select():
> > elections[election.id] = election
>
> > for (k, v) in elections.items():
> > reloaded_election = db.election(k)
> > print k , ' ', v.category, ' ', v.is_presidential()
>
> > Output:
>
> > 81 D False
> > 79 P True
>
> > Does this mean that we can't save rows from DB on Build in types ?
>
> > Thanks in advance,
> > Santiago
