#30053: Allow for conditional QuerySet.update_or_create()
-------------------------------------+-------------------------------------
Reporter: Joshua Cannon | Owner: nobody
Type: New feature | Status: new
Component: Database layer | Version: master
(models, ORM) |
Severity: Normal | Resolution:
Keywords: QuerySet | Triage Stage:
update_or_create | Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Description changed by Joshua Cannon:
Old description:
> {{{QuerySet.update_or_create()}}} is great since it lifts the burden of
> thread-safety and repeated code from the client. However there exists
> some scenarios where the "update" logic should be hidden behind a
> condition. (E.g. only update if the value of a {{{DateTimeField}}} is
> less than somevalue). There isn't much help for clients in these
> scenarios, with the best solution being to copy+paste
> {{{QuerySet.update_or_create()}}} and add a condition to the {{{if
> created:}}} expression.
>
> The condition would most likely be a callable that accepts one argument,
> the {{{got}}}ten instance.
>
> The solution should be trivial, either:
> A. Add a "condition" parameter to {{{update_or_create()}}} (along with
> logic to make the feature backwards compatible, likely checking if the
> value is callable with one argument or not, since "condition" could be a
> field)
> B. Add another method, and re-write {{{update_or_create()}}} in terms of
> the new method with a condition that is always true.
New description:
{{{QuerySet.update_or_create()}}} is great since it lifts the burden of
thread-safety and repeated code from the client. However there exists some
scenarios where the "update" logic should be hidden behind a condition.
(E.g. only update if the value of a {{{DateTimeField}}} is less than some
value). There isn't much help for clients in these scenarios, with the
best solution being to copy+paste {{{QuerySet.update_or_create()}}} and
add a condition to the {{{if created:}}} expression.
The condition would most likely be a callable that accepts one argument,
the {{{got}}}ten instance.
The solution should be trivial, either:
A. Add a "condition" parameter to {{{update_or_create()}}} (along with
logic to make the feature backwards compatible, likely checking if the
value is callable with one argument or not, since "condition" could be a
field)
B. Add another method, and re-write {{{update_or_create()}}} in terms of
the new method with a condition that is always true.
--
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Ticket URL: <https://code.djangoproject.com/ticket/30053#comment:1>
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