Hi,
I'm using sqlalchemy with postgresql-9.3. I'm trying to create a query-able
column in a table that checks for explicit user overrides before checking
the original "raw" data in a JSON column.
An example of what I'm trying to do is below.
The 'raw_data' JSON may be something like: {'foo': 'bar', 'value': 2}. First,
the 'override' column, '_value' is checked for a non-None value, and then
the JSON is checked for key 'value', and then None is returned as the
default.
class MyModel(db.Model):
__tablename__ = 'my_model'
id = db.Column(db.Integer, primary_key=True)
_value = db.Column(db.Integer)
@hybrid_property
def value(self):
if self._value is not None:
return self._value
elif 'value' in self.raw_data and self.raw_data['value'] is not
None:
return self.raw_data['value']
else:
return None
raw_data = db.Column(JSON)
I think hybrid_property is the way to do this, and the 'value' property
works on the instance level, but I can't seem to query on the 'value'
property, like so:
MyModel.query.filter(MyModel.value > 0).all()
Is there a good way to get the functionality I am looking for, as well as
index on the 'value' hybrid_property? Keeping the 'raw_data' JSON column as
is would be preferable, since I plan to refresh that single column
periodically from an external source.
Thanks!
K
--
You received this message because you are subscribed to the Google Groups
"sqlalchemy" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to sqlalchemy+unsubscr...@googlegroups.com.
To post to this group, send email to sqlalchemy@googlegroups.com.
Visit this group at http://groups.google.com/group/sqlalchemy.
For more options, visit https://groups.google.com/d/optout.
