Still getting error message after `except` statement dealing with `ProgrammingError` - mysql

Question

I am using python to automatically populate a MySQL DB. The script that populates the DB (/path/to/pythonScript.py very long) is actually called by another python script (example below) works fine and I have added a few statements that prevent me from inserting duplicated entries.
When I try to insert a duplicated entry with the script /path/to/pythonScript.py I get (as expected)
ProgrammingError: 1061 (42000): Duplicate key name 'unique_index'
In order to deal with that, I want to write a try except statement while calling the /path/to/pythonScript.py script, as shown below:
import mysql.connector
from mysql.connector.errors import ProgrammingError
# Here I have already successfully connected to the DB, and populated it
try:
get_ipython().system("ipython /path/to/pythonScript.py") # this is the script that populates the DB. It does not allow the insertion of duplicated entries
except ProgrammingError:
print("a warning message informing that I am trying to insert a duplicated entry")
When I call the script for the first time, everything goes well (after all, the DB was empty). But then when I call the script for the second time (i.e. when I attempt to insert duplicated entries) I am still getting the same error ProgrammingError: 1061 (42000): Duplicate key name 'unique_index'
I have found this documentation page where they show examples on how to handle errors, though there is no example specifically on the ProgrammingError. In this other documentation page there is one example on the ProgrammingError, though they skipped the imports section and I am afraid I am missing something by the import (note that I don't get any error when I call from mysql.connector.errors import ProgrammingError)?

Answer 1

You are running the other script as a distinct process. Exceptions only exist within the current process - FWIW, you could be running a shell script or a C-coded binary app instead, it would be just the same.
I kindly suggest you momentarily ditch IPython and take a couple days doing the full official Python tutorial, paying particular attention to the parts about functions and modules. Then you may want to rewrite your first script to make it a proper module with proper functions (I assume from your question and example code it's currently a plain script with everything at the top-level - but I may be wrong of course ;) ), then rewrite your calling script to import functions from the first one and call them.
Also note that that ProgrammingError can happen for a whole lot of other reasons than a duplicate key, so you MUST check the exception's code to find out which exact error happened.