The Python Oracle

Flask SQLAlchemy query, specify column names

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Chapters
00:00 Flask Sqlalchemy Query, Specify Column Names
00:28 Answer 1 Score 110
00:43 Answer 2 Score 11
01:16 Accepted Answer Score 332
01:38 Answer 4 Score 85
01:48 Thank you

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Full question
https://stackoverflow.com/questions/1153...

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Content licensed under CC BY-SA
https://meta.stackexchange.com/help/lice...

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Tags
#python #sqlalchemy #flasksqlalchemy

#avk47



ACCEPTED ANSWER

Score 332


You can use the with_entities() method to restrict which columns you'd like to return in the result. (documentation)

result = SomeModel.query.with_entities(SomeModel.col1, SomeModel.col2)

Depending on your requirements, you may also find deferreds useful. They allow you to return the full object but restrict the columns that come over the wire.




ANSWER 2

Score 110


session.query().with_entities(SomeModel.col1)

is the same as

session.query(SomeModel.col1)

for alias, we can use .label()

session.query(SomeModel.col1.label('some alias name'))



ANSWER 3

Score 85


You can use load_only function:

from sqlalchemy.orm import load_only

fields = ['name', 'addr', 'phone', 'url']
companies = session.query(SomeModel).options(load_only(*fields)).all()



ANSWER 4

Score 11


You can use Model.query, because the Model (or usually its base class, especially in cases where declarative extension is used) is assigned Sesssion.query_property. In this case the Model.query is equivalent to Session.query(Model).

I am not aware of the way to modify the columns returned by the query (except by adding more using add_columns()).
So your best shot is to use the Session.query(Model.col1, Model.col2, ...) (as already shown by Salil).