The id field makes each record unique in any table.
db.define_table('collection',
Field('images','list:reference image'),
Field('videos','list:reference video'),
Field('maps','list:reference map'),
...)
# check for reserved keywords before using
On Dec 14, 3:01 pm, Carlos <carlosgali...@gmail.com> wrote:
> Hi,
>
> In object databases, one can define a 1:N relationship (collections)
> pointing to mixed objects (from different classes/tables).
>
> I'm wondering if this is possible with web2py?.
>
> Let's say I have the following separate tables (just as an example,
> not to discuss the actual design):
> - image
> - video
> - map
>
> And I need certain objects to hold collection (let's call it
> 'resources') of these mixed objects in certain order, i.e. one single
> collection of many of [ image / video / map ] ... and there could be
> many collections of different types and elements.
>
> Is "uuid" useful for this case?, does uuid generate a unique id for an
> object (table + record id) across the complete database (across all
> tables and their records)?, should uuid be used in addition to or
> instead of "id"?, does web2py keep referential integrity if uuid is
> used instead of id?, is all this portable across all supported
> databases?.
>
> Or should I simply use a computed field that concatenates table_name +
> record_id?.
>
> At this point I don't really care about uniqueness across multiple
> databases, but instead only uniqueness within a single database
> (across tables and records).
>
> In other words, I want to be able to identify "instances" by a single
> id (which would internally know the table name and record id).
>
> I'm not sure if I'm explaining correctly?.
>
> Please let me know if there's something already built-in in web2py, or
> any other recommendations you might have.
>
> Thanks,
>
> Carlos
