#25091: Array field equality lookup fails with ProgrammingError
----------------------------------+------------------------------------
Reporter: unklphil | Owner:
Type: Bug | Status: new
Component: contrib.postgres | Version: master
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
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Comment (by calvingiles):
I have found two simple workarounds to this, but they may have some issues
that I am not aware of. The first is to pass the array to the get or
get_or_create method not as a list, but as a string formatted using
{{{
'{1.0, 2.0}'
}}}
instead of
{{{
ARRAY[1.0, 2.0]
}}}
which causes postgres to handle an implicit cast from numeric to real
(which I needed in this case).
The other is to perform this conversion in `get_db_prep_value()` by
overriding the ArrayField class. For my specific case, this appears to
work, but it may not be robust to arrays of different types (especially
strings):
{{{
class StrFormatArrayField(ArrayField):
"""
Override the array format to use "'{1.0, 2.0, 3.0}'" instead of
"ARRAY([1.0, 2.0, 3.0])"
to get around an issue with implicit type conversion.
"""
def get_db_prep_value(self, value, connection, prepared=False):
if isinstance(value, list) or isinstance(value, tuple):
prepped = [self.base_field.get_db_prep_value(i, connection,
prepared) for i in value]
joined = ', '.join([str(v) for v in prepped])
return '{' + joined + '}'
else:
return value
}}}
Any advice on improving upon this or issues I may face would be greatly
appreciated.
--
Ticket URL: <https://code.djangoproject.com/ticket/25091#comment:4>
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