python sqlalchemy AttributeError: 'BaseQuery' object has no attribute 'id'

Question

I'm trying to set the foreign_key column of the table by using data from another table 'Nutritional Values'

class NutritionalValues(db.Model):
    __tablename__ = 'nutritionalvalues'
    id = db.Column(db.Integer, primary_key=True)
    item = db.Column(db.String(200), nullable=False)
    calories = db.Column(db.Float, nullable=False)
    totalfat = db.Column(db.Float, nullable=False)

by using

consumed_nutrionalvalue_id = NutritionalValues.query.filter_by(item=consumed_item).id

where 'consumed_item' is some string that exactly matches the string of the 'item' value for one row of the NutritionalValues table

but I get the error

AttributeError: 'BaseQuery' object has no attribute 'id'

Traceback (most recent call last)
File "/Users/benjamattesjaroen/helloPython/env/lib/python3.7/site-packages/flask/app.py", line 2463, in __call__
return self.wsgi_app(environ, start_response)
File "/Users/benjamattesjaroen/helloPython/env/lib/python3.7/site-packages/flask/app.py", line 2449, in wsgi_app
response = self.handle_exception(e)
File "/Users/benjamattesjaroen/helloPython/env/lib/python3.7/site-packages/flask/app.py", line 1866, in handle_exception
reraise(exc_type, exc_value, tb)
File "/Users/benjamattesjaroen/helloPython/env/lib/python3.7/site-packages/flask/_compat.py", line 39, in reraise
raise value
File "/Users/benjamattesjaroen/helloPython/env/lib/python3.7/site-packages/flask/app.py", line 2446, in wsgi_app
response = self.full_dispatch_request()
File "/Users/benjamattesjaroen/helloPython/env/lib/python3.7/site-packages/flask/app.py", line 1951, in full_dispatch_request
rv = self.handle_user_exception(e)
File "/Users/benjamattesjaroen/helloPython/env/lib/python3.7/site-packages/flask/app.py", line 1820, in handle_user_exception
reraise(exc_type, exc_value, tb)
File "/Users/benjamattesjaroen/helloPython/env/lib/python3.7/site-packages/flask/_compat.py", line 39, in reraise
raise value
File "/Users/benjamattesjaroen/helloPython/env/lib/python3.7/site-packages/flask/app.py", line 1949, in full_dispatch_request
rv = self.dispatch_request()
File "/Users/benjamattesjaroen/helloPython/env/lib/python3.7/site-packages/flask/app.py", line 1935, in dispatch_request
return self.view_functions[rule.endpoint](**req.view_args)
File "/Users/benjamattesjaroen/helloPython/app.py", line 65, in index
consumed_nutrionalvalue_id = NutritionalValues.query.filter_by(item=consumed_item).id
AttributeError: 'BaseQuery' object has no attribute 'id'

but cleary 'Nutritional Values' does have a column called 'id'? How can I access the integer stored in that column of the table for my query?

NutritionalValues.query.filter_by(item=consumed_item) is a query. You need to use .first() to get the object. — Andrew Allen
– Andrew Allen, Commented Oct 10, 2019 at 9:27
some_query.first().id should work, I've just tested similar code. — Andrew Allen
– Andrew Allen, Commented Oct 10, 2019 at 9:46

Andrew Allen · Accepted Answer · 2019-10-10 09:50:41Z

19

The following is a query

NutritionalValues.query.filter_by(item=consumed_item)

To get the object (this o in orm) you can use .first() or for many results .all()

NutritionalValues.query.filter_by(item=consumed_item).first()

You now have a normal object you can do pythonic methods to such as member access.

This is interesting because you can build dynamic queries before the execution that gets the results.

answered Oct 10, 2019 at 9:50

Andrew Allen

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1 Comment

Yashasvi Bhatt Over a year ago

the problem with me is when i return results using return render_template('<template-name>', post='<object-name>'), and now access them using {{ post.<utility> }}, the utility won't fetch instead it displays the query. Any help!

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