Save ResultSet to a File

At work I had a huge query with many inner joins and also an inner query that was taking forever and wouldn't always return, it would error out instead. (Turns out the main problem was hitting a very active DB but when I switched to a backup DB the query worked fine.)

Anyways, in order not to worry about making the query whenever I wanted to test something I decided to save the Python resultset to a file. I wanted to save it in such a way as that when I read it back in it was as if I was using the resultset.

Pickle didn't seem to "easily" work, i.e. after a few tries I just gave up on it. But after some Googling I found this solution which is just what I wanted.

Execute query, fetch data into a resultset

Convert the result set to tuples and save

toops = [tuple(row) for row in rows]

with open('some_file.dat', 'w') as f:
    for tup in toops:
        f.write(f'{tup}\n')

Read data back in

toops = []
with open('some_file.dat') as f:
    for line in f.readlines():
        toops.append(eval(line))

Note:

If the data has any python datetime objects or Decimal objects then you will need to import the following:

import datetime
from decimal import *

You can now use toops as if it were toops = results.fetchall()