[web2py] Concatenate str and int values in Model

[greenpoise]

How could I concatenate two db field values in my Model?? My example
is this:

db.define_table('vlanman',
    Field('person',db.person,default=None),
    Field('switchselect'),
    Field('locationprefix'),
    Field('patchpanel'),
    Field('patchnumber'),
    Field('switchnumber'),
    Field('location'),
    Field('workstation'),
    Field('diagram','upload'))

I want location to be a combination of locationprefix (string) and
patchnumber (int)??


Thanks
dan