Should the slug for City, Region and Country be unique?

[unxavi]

I am not sure if i am confused, but i understand that the base model define the field "slug" with the intention of being unique. But for example for cities at least it is not, a search for "valencia" as the slug returns 4 results.

When doing a detail view searching a city by the slug field, returns an error, because it finds 4 objects and not one.

So, shouldnt the "slug" field be define as unique?

Thanks very much by the way, think i will be using this, so i hope to help around

[jpic]

I don't see how we could define the city slug as unique.

[unxavi]

It might be a stupid question but at least i will know the why.

In yours models module, your "Base" Class, the slug field, shouldnt it be define as unique=True?

I mean this line:

slug = autoslug.AutoSlugField(populate_from='name_ascii')

Could it be?

slug = autoslug.AutoSlugField(populate_from='name_ascii', unique=True)

[jpic]

The problem is that many cities have the same name, and sometimes even the same country like springfield (USA).

[unxavi]

If they have the same name, like cities do, isn't that a reason to work with unique slugs?

thats why i ask about define a unique slug for the countries, cities, and regions.... so if a city has the same name as others and same country, etc... you can still reach them by a different slug in the url and not by the pk.

I tested the change i mentioned, so I got unique slugs.

Example:

If you want, I can make the change and ask for a pull request. it takes like 1 more minute on the import all because of the time checking unique slugs.

I dont know if i make myself clear about why the unique slugs.

In the springfield case the result is getting different slug for every city, while you can still keep the name and name_ascii as "Springfield"

let me know what you think about this change, i dont see the point of having 11 cities with the same slug "springfield" for all of them.

Anyways thanks

[jpic]

Well the point is to have urls of /country-slug/region-slug/city-slug/ like:

/united-states/texas/springfield/ /united-states/virginia/springfield/

I think it would break urls if we changed that to append random numbers at the end of city slug names, so I'm not going to pull it.

Also, I recommend that you prefix your city urls with region and country slugs.

[unxavi]

Hey,

Cool, thanks for your answer, I see your point with the URLs

This approach if I am not wrong would not include the edge case where you have two cities with the same name in the region.

I have load the 5000 cities file and do some search with the ORM and I found some of this cases:

This is Country, Region and the count and the slugs that repeat:

Canada Quebec, Canada [{'count': 2, 'slug': u'pont-rouge'}]
Germany Bavaria, Germany [{'count': 2, 'slug': u'pocking'}]
Greece Attica, Greece [{'count': 2, 'slug': u'marousi'}]
India Andhra Pradesh, India [{'count': 2, 'slug': u'ramapuram'}]
India Madhya Pradesh, India [{'count': 2, 'slug': u'katangi'}]
India Maharashtra, India [{'count': 2, 'slug': u'jalgaon'}]
India Uttar Pradesh, India [{'count': 2, 'slug': u'tanda'}]
Mexico Yucatán, Mexico [{'count': 2, 'slug': u'panaba'}]
Pakistan Punjab, Pakistan [{'count': 2, 'slug': u'sahiwal'}]
Philippines Autonomous Region in Muslim Mindanao, Philippines [{'count': 2, 'slug': u'pagalungan'}]

Using this code:

for country in countries:
    for region in country.region_set.all():
        dupas = region.city_set.values('slug').annotate(count=Count('id')).order_by().filter(count__gt=1)
        if len(dupas) > 0:
            print country, region, dupas

The thing is, if you use the URL as you indicate, if someone enters the detail to a city where in the region there are two, your django view will generate an error, because it will try to do a get on a field where there are two results.

A search in the admin show this:

¿How do you handle this cases?

[jpic]

I'm going to have a look but the first thing that comes to my mind is "that's weird" because City.Meta.unique_together has ('region', 'name')​.

[unxavi]

Hi,

I have been reviewing the code and looked at that too… I am not django or db expert or anything… but I think that: City.Meta.unique_together has ('region', 'name').

Can hold together, because if I look at the cases found (with the 5000 cities file) I see the actual names are non ascii characters different.

For example:

First case:

Country Canada, Region Quebec, Canada.

2 cities found with the slug “pont-rouge”

One with the actual name "Pont Rouge" and the second one "Pont-Roug".. I don’t know if this is normal, so the have different name, the unique together hold fine, but they both produce same slug, which break the view with the url:

/canada/quebec/pont-rougue

The others cases about the same:

Germany Bavaria

Slug: pocking

One city with the name “Pocking” and the other “Pocking”

Attica, Greece

Slug: marousi One city with the name “Marousi” and the other “Maroúsi”

Andhra Pradesh, India

Slug: ramapuram

One city with the name “Ramāpuram” and the other “Rāmāpuram”

And like this the rest of the duplicates.

Thanks very much for all your comments on the subject.

[unxavi]

Hi again,

Also I am trying to use the http://download.geonames.org/export/dump/cities1000.zip file for the import... but i keep getting this error:

File "manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "/home/vagrant/project-env/lib/python2.7/site-packages/django/core/management/__init__.py", line 399, in execute_from_command_line
    utility.execute()
  File "/home/vagrant/project-env/lib/python2.7/site-packages/django/core/management/__init__.py", line 392, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/home/vagrant/project-env/lib/python2.7/site-packages/django/core/management/base.py", line 242, in run_from_argv
    self.execute(*args, **options.__dict__)
  File "/home/vagrant/project-env/lib/python2.7/site-packages/django/core/management/base.py", line 285, in execute
    output = self.handle(*args, **options)
  File "/home/vagrant/project-env/lib/python2.7/site-packages/django/db/transaction.py", line 399, in inner
    return func(*args, **kwargs)
  File "/home/vagrant/project-env/lib/python2.7/site-packages/cities_light/management/commands/cities_light.py", line 162, in handle
    self.city_import(items)
  File "/home/vagrant/project-env/lib/python2.7/site-packages/cities_light/management/commands/cities_light.py", line 321, in city_import
    city = City.objects.get(**kwargs)
  File "/home/vagrant/project-env/lib/python2.7/site-packages/django/db/models/manager.py", line 151, in get
    return self.get_queryset().get(*args, **kwargs)
  File "/home/vagrant/project-env/lib/python2.7/site-packages/django/db/models/query.py", line 310, in get
    (self.model._meta.object_name, num))
cities_light.models.MultipleObjectsReturned: get() returned more than one City -- it returned 2!

What do you think? may be a violation of foreing key or something like this?

Thanks again mate!

[unxavi]

James,

Sabes de alguna manera de evitar estos casos aislados?

Gracias

[jpic]

Well you can always skip the data you want using signals.

I'm currently fixing the bug.