Re: Filtering on model methods

On Thu, Oct 29, 2009 at 10:18 AM, pbzRPA wrote: > It's a pity django does not provide this kind of > functionality. hum it would be a pretty impressive feat for an ORM to take some arbitrary python code and recompile it to (portable!) SQL to make the DB do the work. --

Re: Filtering on model methods

Thank you for your help. I guess I will have to create temp table etc and do it that way. It's a pity django does not provide this kind of functionality. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Django users"

Re: Filtering on model methods

I think if your methods are really complex then the best you can do is to denormalise your DB. Make your calculated fields real fields in a table and update them in model's save method or using signals. Another way is to make them calculated by DB using triggers or DB views but I would prefer

Re: Filtering on model methods

I think my problem is both 1 and 2. What happens when you want to use python modules to analyse the extra field? For Example: Database table History: id | Ordered | Delivered | Invoiced | 1 10 15 5 2 553

Re: Filtering on model methods

Maybe I wrote a reply without undersanding what you need. You have 2 separate issues: 1. Want to sort and filter by calculated field 2. Want to create calculated field that is calculated in python Am I correct? 1) can be acheived using ".extra" method or aggregations

Re: Filtering on model methods

Thanks for you reply Mikhail, I do use model managers but more often to get a certain defined queryset back. Could you maybe show me a simple example of how to implement your suggestion? I imagine it looking something like this. class PersonManager(models.Manager): def

Re: Filtering on model methods

If you want to be able to sort by some python method you have to fetch ALL data from all tables that are used in this method. It is indeed a bad practice and so it is not encouraged in django. The best you can do is to put your code to model's manager as a method. Model managers are often used

Re: Filtering on model methods

Sorry I would also like to add that I would like to sort by this field in generic views. So results = Person.objects.filter (compare_to_others__gte = 1).order_by('compare_to_others') --~--~-~--~~~---~--~~ You received this message because you are subscribed to

Filtering on model methods

Hi all, I keep running into a problem. Often when creating models for existing databases which you can not modify, I find myself in need of quite a few model methods. That all works fine but then when I run a view I would like to be able to use the object mapper to filter by the method on a