Opened 3 years ago
Last modified 2 months ago
#31300 assigned New feature
Add function-based virtual fields.
Reported by: | Dulmandakh | Owned by: | Jeremy Nauta |
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Component: | Database layer (models, ORM) | Version: | dev |
Severity: | Normal | Keywords: | |
Cc: | Petr Přikryl, elonzh | Triage Stage: | Accepted |
Has patch: | yes | Needs documentation: | no |
Needs tests: | no | Patch needs improvement: | no |
Easy pickings: | no | UI/UX: | no |
Description
PostgreSQL 12 added support for Generated Columns, see https://www.postgresql.org/docs/12/ddl-generated-columns.html. And I find it very interesting and useful, for example with SearchVectorField.
I imagine it would be called GeneratedField and accept base_field as ArrayField, then expression to generate a value for the field. For example,
class Album(models.Model): ... title = models.CharField(max_length=120) search = GeneratedField( SearchVectorField(), F('title') )
then generate SQL something like below.
CREATE TABLE album ( ... title char(120), search tsvector GENERATED ALWAYS AS title STORED );
I would like to work on this feature, but don't know how to pass expression and generate migration using the expression.
Change History (8)
comment:1 Changed 3 years ago by
Resolution: | → wontfix |
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Status: | new → closed |
Summary: | Add Generated Columns (PostgreSQL) support → Add function-based virtual fields on PostgreSQL and Oracle. |
comment:2 Changed 2 years ago by
Cc: | Petr Přikryl added |
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comment:3 Changed 5 months ago by
Resolution: | wontfix |
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Status: | closed → new |
Summary: | Add function-based virtual fields on PostgreSQL and Oracle. → Add function-based virtual fields. |
Triage Stage: | Unreviewed → Accepted |
Tentatively accepted, based on the feedback from the mailing list.
comment:4 Changed 5 months ago by
Has patch: | set |
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Owner: | changed from nobody to Jeremy Nauta |
Patch needs improvement: | set |
Status: | new → assigned |
comment:5 Changed 5 months ago by
Cc: | elonzh added |
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comment:6 Changed 2 months ago by
Patch needs improvement: | unset |
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comment:7 Changed 2 months ago by
Patch needs improvement: | set |
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comment:8 Changed 2 months ago by
Patch needs improvement: | unset |
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We have an accepted ticket #30511 about identity columns on PostgreSQL, and I think we should stay with this. Generated/Function-based virtual columns are a huge topic that would require many changes and have many caveats, e.g. functions must be deterministic. They are feasible also on Oracle. This kind of features require few weeks (even months) of works, a precise plan, and should be preceded by a discussion on DevelopersMailingList and even DEP.