Deserializing JSON in SQLAlchemy when using raw SQL

Question

I have a table with JSON stored in a text column:

import json
from sqlalchemy import create_engine, Column, text, Integer, TEXT, TypeDecorator
from sqlalchem         


        

Answer 1

You can tell TextClause (produced by text()) the column types using .columns():

from sqlalchemy import inspect

session = Session()
stmt = text('select * from t').columns(*inspect(T).columns)
t = session.query(T).from_statement(stmt).first()
assert type(t.attrs) == dict, repr(t.attrs)

Or, for SQLAlchemy<0.9, use the typemap argument:

from sqlalchemy import inspect

session = Session()
typemap = {c.name: c.type for c in inspect(T).columns}
stmt = text('select * from t', typemap=typemap)
t = session.query(T).from_statement(stmt).first()
assert type(t.attrs) == dict, repr(t.attrs)