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?

Answer 1

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.