That's working exactly as I want it to. I'm just in the initial building
phase right now, and given the purpose of the application, speed isn't
critical. Still, it's nice to know that it's more efficient to use
IS_IN_SET.
I should have known that requires(db, db.something) and db.something are
different because it doesn't seem like web2py would have been designed with
more than one way to perform a given task. Thanks for the insight!
On Tuesday, January 28, 2014 11:13:27 AM UTC-8, Ryan Matlock wrote:
>
> It appears that there are two ways to get a field to reference another
> table,
> Field("my_field", requires=IS_IN_DB(db, db.some_table))
> and
> Field("my_field_2", db.some_table_2)
>
> The problem with both of these (and especially the first one), is that I
> can't seem to get the format for my_field to grab the format of some_table
> and my_field_2 can't grab the format from tables that some_table_2 uses in
> its format.
>
> To be more concrete about it, I'm building an application that tracks
> service work done on vehicles. I'd like to have a table of manufacturers,
> then a table that references the manufacturers and associates them with
> models, then configurations of those models, then particular vehicles that
> associate a configuration and an owner with other data like the VIN. In
> both formulations that I've tried, the admin interface becomes incredibly
> confusing because I'm mostly having to remember what id is associated with
> a particular entry. Here's a simplified version of my code so far:
>
> db.define_table("test_person",
> Field("fname",
> requires=IS_NOT_EMPTY()),
> Field("lname",
> requires=IS_NOT_EMPTY()),
> format = "%(fname)s %(lname)s")
>
> db.define_table("test_manufacturer",
> Field("name"),
> format = "%(name)s")
>
> db.define_table("test_model",
> Field("manufacturer",
> requires=IS_IN_DB(db, db.test_manufacturer)),
> Field("model_year"),
> Field("model"),
> format = "%(model_year)s %(manufacturer)s %(name)s")
>
> db.define_table("test_model_configuration",
> Field("model",
> requires=IS_IN_DB(db, db.test_model)),
> Field("config",
> label="Configuration"),
> format = "%(model)s %(config)s")
>
> db.define_table("test_vehicle",
> Field("vehicle_owner",
> requires=IS_IN_DB(db, db.test_person)),
> Field("model_config",
> requires=IS_IN_DB(db, db.test_model_configuration),
> label="model"),
> Field("vin",
> label="VIN"),
> format = "%(vehicle_owner)s's %(model)s")
>
> db.define_table("test_model_2",
> Field("manufacturer",
> db.test_manufacturer),
> Field("model_year"),
> Field("model"),
> format = "%(model_year)s %(manufacturer)s %(model)s")
>
> db.define_table("test_model_configuration_2",
> Field("model",
> db.test_model_2),
> Field("config",
> label="Configuration"),
> format = "%(model)s %(config)s")
>
> db.define_table("test_vehicle_2",
> Field("vehicle_owner",
> db.test_person),
> Field("model_config",
> db.test_model_configuration_2,
> label="model"),
> Field("vin",
> label="VIN"),
> format = "%(vehicle_owner)s's %(model)s")
>
> I suppose I could get this to work if I had a "flatter" database. That
> is, if I stuffed the manufacturer, model, and configuration into a single
> table, the vehicle would only be "looking up" one table and could grab all
> the information it needed. However, I can see this being a problem when I
> want to start doing things with the vehicles (e.g. "John Doe's 1999 Honda
> Accord LX"), which I don't want to be displayed as "82's 16 1" for which
> I'd have to look up the id numbers to make any sense of it.
>
> If I need to ignore the admin interface entirely during this initial
> testing phase, I'm still not sure what the most Pythonic/web2pythonic way
> of getting all the information into my views is. My guess is that it would
> be done in the controller by making a dictionary associating id numbers
> with desired formats, but that seems like it would require a lot of
> looping, which would bog everything down in a large-scale application.
>
> Basically, I'm completely stumped as to the "right" way to proceed.
>
--
Resources:
- http://web2py.com
- http://web2py.com/book (Documentation)
- http://github.com/web2py/web2py (Source code)
- https://code.google.com/p/web2py/issues/list (Report Issues)
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