Opened 11 years ago
Last modified 10 years ago
#20971 closed Bug
Annotating a count of distinct ForeignKey (a) of a reverse foreignkey (b) doesn't work on oracle if (a) has any TextFields — at Initial Version
| Reported by: | Owned by: | nobody | |
|---|---|---|---|
| Component: | Database layer (models, ORM) | Version: | 1.5 |
| Severity: | Normal | Keywords: | oracle |
| Cc: | Triage Stage: | Accepted | |
| Has patch: | no | Needs documentation: | no |
| Needs tests: | no | Patch needs improvement: | no |
| Easy pickings: | no | UI/UX: | no |
Description
If there is a model X that has foreignkey to model Y and X has foreign key to Z and has TextFields the query for an instance of Y fails.
E.g.
y.xys.all().defer(list_of_all_text_fields).annotate(Count('zpk', distinct=True) causes "DatabaseError: ORA-00932: inconsistent datatypes: expected - got NCLOB"
This is probably(?) because the "GROUP BY" clause will contain all the deferred fields.
As a workaround I have to do sum(len(set(x)) for x in y.xys.all().values_list('zpk'))
Works flawlessly on PostgreSQL.
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