Django: Error with inserting dictionary to my_model.objects.raw() method - django

Question

I'm performing a query in a function inside the views.py as follows:
input_dict = {'id': 'id',
'table': 'my_table',
'first_col': 'my_first_col',
'first_name': 'my_first_name'}
query = '''
SELECT %(id)s
FROM %(table)s
WHERE %(first_col)s = %(first_name)s '''
qs = my_model.objects.raw(query, input_dict)
print(qs)
which prints:
qs: <RawQuerySet:
SELECT id
FROM my_table
WHERE my_first_col = my_first_name >
However, when I try to run this line:
ids = [item.id for item in qs]
it gives me an error:
psycopg2.errors.SyntaxError: syntax error at or near "'my_table'"
LINE 3: FROM 'my_table'
and also:
django.db.utils.ProgrammingError: syntax error at or near "'my_table'"
LINE 3: FROM 'my_table'
What should I do?

Answer 1

django are not able to excecut your query.
I believe what you trying to acheive via the raw function it is not possible.
read the docs https://docs.djangoproject.com/en/3.0/topics/db/sql/ for better understanding how the function work
your dynamic options are realted either to the table fields and the where params:
the select fields
you can map fields in the query to model fields using the translations
argument to raw()
like :
name_map = {'first': 'first_name', 'last': 'last_name', 'bd': 'birth_date', 'pk': 'id'}
Person.objects.raw('SELECT * FROM some_other_table', translations=name_map)
the where params
If you need to perform parameterized queries, you can use the params
argument to raw()
lname = 'Doe'
Person.objects.raw('SELECT * FROM myapp_person WHERE last_name = %s', [lname])
at the end of the day, this will work, although it's not recomended unless you know exactly what you are doing as it might expose your system to sql attacks
query = '''
SELECT %(id)s
FROM %(table)s
WHERE %(first_col)s = %(first_name)s '''
query = query%input_dict
qs = my_model.objects.raw(query)