How can I add dynamic field in the model in django?

I'm using django to create a applic开发者_JS百科ation download site. I try to write a model, that the admin can add the different download content dynamically in the admin page. For example I have a software named foobar, it have 3 different version: 1.1, 1.2, 1.3. I would like the user can admin the model by using an add button to add the download link with a download version. But I don't know how to do this in django.

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Set up your models to have a main model and ancillary models that have foreign keys to the main model:

class DownloadItem(models.Model):

   name = models.CharField( etc etc)
   ... other attributes here ...


class DownloadItemFile(models.Model):
   parent = models.ForeignKey('DownloadItem', related_name="versions")
   version = models.CharField( etc etc)
   file = models.FileField(upload='path/to/uploaddir/')

then, when you have an instance of your DownloadItem model, you can get hold of your various file versions with:

mydownloaditem.versions.all()

To be able to add files via the Admin, you will need to use an inline. In your admin.py for the app in question, you'll need to add something like:

class DownloadItemFileInline(admin.TabularInline):
    model           = DownloadItemFile

class DownloadItemAdminOptions(admin.ModelAdmin):
    inlines         = [ DownloadItemFileInline, ]
    ...other admin options here...    

admin.site.register(DownloadItem, DownloadItem AdminOptions)