#29049: Add slicing notation to F expressions
-------------------------------------+-------------------------------------
Reporter: Matthew Pava | Owner: Abhinav
| Yadav
Type: New feature | Status: assigned
Component: Database layer | Version: dev
(models, ORM) |
Severity: Normal | Resolution:
Keywords: slice F | Triage Stage: Accepted
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 1
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Comment (by Abhinav Yadav):
I have been reading up about this issue to continue and finish it off from
where David left it, and I have some doubts. The SQL query left by Felix
[https://github.com/django/django/pull/14731#discussion_r745505740 in this
comment] also doesn't generate any QuerySet or objects. I tried to run
that query using `Manager.raw()`, which generated no results.
Further I investigated the `resolve_expression` method of `SliceableF`
class in `django/db/models/expressions.py`, and compared it to other
implementations of resovle_expression method in other classes but couldn't
find anything concrete which might point to where the error might be.
Does a special method for handling slicing and indexing for OuterRef query
need to be written so it is properly resolved? That is what I'm thinking
because I can't find anything else that is properly handling slicing for
OuterRef Queries, unless I'm missing something.
Also should `None` be used instead of `''` in slice_expression for end if
length is not provided?
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Ticket URL: <https://code.djangoproject.com/ticket/29049#comment:22>
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