#33595: Check Constraint on nullable BooleanField should not be simplified
-------------------------------------+-------------------------------------
Reporter: Peter Law | Owner: nobody
Type: Bug | Status: closed
Component: Database layer | Version: 3.2
(models, ORM) |
Severity: Normal | Resolution: invalid
Keywords: | Triage Stage:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
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Changes (by Mariusz Felisiak):
* status: new => closed
* resolution: => invalid
Comment:
Thanks for this ticket, however that's how a `CHECK` constraints works in
all databases and that's why not-null constraints exist, see for example
PostgreSQL [https://www.postgresql.org/docs/current/ddl-constraints.html
docs]:
> ''"It should be noted that a check constraint is satisfied if the check
expression evaluates to true or the null value. Since most expressions
will evaluate to the null value if any operand is null, they will not
prevent null values in the constrained columns. To ensure that a column
does not contain null values, the not-null constraint described in the
next section can be used."''
Switching to `"it_exists" = TRUE` wouldn't change this behavior. You
should use `models.BooleanField(null=False)` or explicitly add `__isnull`
to `check=models.Q(it_exists=True, is_exists__isnull=False)`.
--
Ticket URL: <https://code.djangoproject.com/ticket/33595#comment:1>
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