On 30 jan, 13:46, Russell Keith-Magee <freakboy3...@gmail.com> wrote: > If you are interested in implementing this, I'm happy to give you > pointers. The first pointer I can suggest is that you will be looking > at the SQLEvaluator class contained in > django/db/models/sql/expressions.py. This class traverses the > expression tree, turning it into raw SQL. The actual expression tree > is a series of tree.Node objects defined in > django/db/models/expressions.py. > > Also - anything you do here shouldn't be date-specific. Other data > types - such as strings and GIS types - will require similar > capabilities. Try to keep that in mind when you are looking to > potential solutions for the date problem. > > > It seems though that the different backends will certainly need > > different handlings: > > Indeed. The Postgres option should be fairly easy to implement - you > just need to replace leaf nodes on the expression tree that are > timedeltas with matching "interval X" statements. SQLite style > expressions will be a little harder. > > Yours, > Russ Magee %-)
I made a first attempt, see ticket #10154. Idea is to use a specific node (and leaf) for combinations of an expression with a timedelta. I put the backend specifics into the relevant Operations classes (for now only base (= sqlite implementation) and postgres). sqlite and postgres pass the test. The dispatching based on 'other' being a timedelta needs refining though, since this is obviously not generic enough. Koen --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@googlegroups.com To unsubscribe from this group, send email to django-users+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/django-users?hl=en -~----------~----~----~----~------~----~------~--~---
