Opened 22 months ago

Closed 2 days ago

#22936 closed Cleanup/optimization (fixed)

Get rid of field.get_db_prep_lookup()

Reported by: akaariai Owned by: nobody
Component: Database layer (models, ORM) Version: master
Severity: Normal Keywords:
Cc: Triage Stage: Ready for checkin
Has patch: yes Needs documentation: no
Needs tests: no Patch needs improvement: no
Easy pickings: no UI/UX: no

Description (last modified by timgraham)

The Field.get_db_prep_lookup() method is used to do preparation of a plain Python value for given lookup. Looking at the coding of get_db_prep_lookup() the get_db_prep_lookup() is doing work that belongs into the lookup itself.

The same goes also for get_prep_lookup(). It seems that get_prep_lookup() is either doing something that should actually be done in get_prep_value(), or something that belongs into lookups.

If a custom field needs to do different kind of preparation for some lookups (something that can't be done in get_[db_]prep_value(), it can always provide a lookup subclass that does the right thing for that field type. An example is IntegerField and 'lt' and 'gte' lookups. Providing custom subclasses might be laborious to do if there are a lot of different lookup types that need custom preparation. For that reason a hook for custom fields could still be useful.

Even if we want to leave get_db_prep_lookup and get_prep_lookup hooks for custom fields, the base coding belongs into the lookups themselves. Currently the fields are doing work that clearly belongs to the lookup itself.

Change History (9)

comment:1 Changed 22 months ago by timo

  • Description modified (diff)
  • Triage Stage changed from Unreviewed to Accepted

comment:2 Changed 4 weeks ago by timgraham

  • Description modified (diff)

As suggested in the ticket description, I did the small step of moving IntegerField.get_prep_lookup() to lookup subclasses: PR.

comment:3 Changed 3 weeks ago by Tim Graham <timograham@…>

In 1c30a647:

Refs #22936 -- Moved IntegerField.get_prep_lookup() logic to lookups.

comment:4 Changed 13 days ago by claudep

This PR removes the get_prep_lookup method.

comment:5 Changed 11 days ago by Tim Graham <timograham@…>

In 1ba0b22:

Refs #22936 -- Removed unused code in Field.get_db_prep_lookup().

comment:6 Changed 4 days ago by Tim Graham <timograham@…>

In eab5df1:

Refs #22936 -- Moved more of Field.get_db_prep_lookup() to lookups.

comment:7 Changed 3 days ago by timgraham

  • Has patch set

I submitted a PR to Claude's PR in comment:4 which completes the ticket.

comment:8 Changed 3 days ago by timgraham

  • Triage Stage changed from Accepted to Ready for checkin

comment:9 Changed 2 days ago by Claude Paroz <claude@…>

  • Resolution set to fixed
  • Status changed from new to closed

In 388bb5b:

Fixed #22936 -- Obsoleted Field.get_prep_lookup()/get_db_prep_lookup()

Thanks Tim Graham for completing the initial patch.

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