Excellent! This works just as advertised for obtaining the companies and
the solution works in my application. I very much appreciate the solution.
I was wondering if this was analogous to the following syntax in Django:
train.objects.filter(company__name='Amtrak')
Please, no offense, because I absolutely love web2py, but the Django syntax
in this case is much more understandable. Also, if there are more
relationships to track such as:
blog.objects.filter(entry__author__name='Dave')
you are able to arbitrarily track any relationship with this syntax. If
this isn't possible, or if I have misinterpreted the syntax and
functionality, please let me know.
Thank you very much for (a) creating such a great framework and (b) for
being so committed to helping here on the forums!
Dave
On Friday, January 11, 2013 7:13:36 PM UTC-5, Massimo Di Pierro wrote:
> I think you want (I am changing some field names because user and date are
> resrved keywords):
>
> db.define_table('company',
> Field('name'),
> Field('symbol'))
>
> db.define_table('train',
> Field('user_id', 'reference auth_user', default=auth.user_id),
> Field('company', db.company),
> Field('date_event', 'date'),
> Field('num_cars'))
>
>
> companies =
> db(db.company.id.belongs(db(db.train.user_id==id)._select(db.train.company,distinct=True)).select(orderby=
> db.company.name)
>
>
>
>
> On Friday, 11 January 2013 17:05:02 UTC-6, Dave Cenker wrote:
>>
>> I am putting together a website for my son so that he can keep track of
>> trains that he has seen in our area. Here are the applicable models:
>>
>> db.define_table('company',
>> Field('name'),
>> Field('symbol'))
>>
>> db.define_table('train',
>> Field('user', 'reference auth_user', default=auth.user_id),
>> Field('company', db.company),
>> Field('date', 'date'),
>> Field('numCars'))
>>
>> I would like to be able to select all the trains that a particular user
>> has seen. I believe I can accomplish this with the following:
>>
>> currUserQuery = db.train.user == auth.user_id
>> allTrainsSeenByUser = db(currUserQuery).select(orderby='date desc')
>>
>> What I would like to do is create an index page for each user that splits
>> out the trains of each company that have been seen. For example, assume
>> that there are three companies in the database: Amtrak, CSX, and BNSF. Of
>> these three companies the user has seen trains from Amtrak and CSX. On
>> their index page, they would see all the Amtrak trains that they have seen
>> grouped together and all the CSX trains that they have seen grouped
>> together. Therefore, I would like to perform a database selection that
>> finds all the trains for a particular user and a particular company.
>>
>> I have found a way to determine which companies a particular user has
>> seen using the following:
>>
>> companies = db(currUserQuery).select('train.company',
>> distinct=True).as_list()
>>
>> However, this returns a list of company IDs instead of names and when I
>> try to do something like this:
>>
>> db(train.company.id == id) it doesn't work.
>>
>> What I'd really like to do is get a list of the names of the companies
>> that a user has seen and then make a database selection based upon those
>> names in a manner like this:
>>
>> db(currUserQuery & (db.train.company.name == companyNameText)).select()
>>
>> However, the db.train.company.name doesn't work. Is there a way to
>> progress down the hierarchy (if you will) to access the company name on a
>> particular train row given the database structure above. With Django (which
>> I have used in the past), this would be accomplished similar to this
>> (train__company__name=companyNameText), but I can't figure out the
>> corresponding way to do so in web2py.
>>
>> Thanks for any help you can provide!
>>
>> Dave
>>
>>
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