Question

I’m creating a basic database utility class in Python. I’m refactoring an old module into a class. I’m now working on an executeQuery() function, and I’m unsure of whether to keep the old design or change it. Here are the 2 options:

1. (The old design:) Have one generic executeQuery method that takes the query to execute and a boolean commit parameter that indicates whether to commit (insert, update, delete) or not (select), and determines with an if statement whether to commit or to select and return.
2. (This is the way I’m used to, but that might be because you can’t have a function that sometimes returns something and sometimes doesn’t in the languages I’ve worked with:) Have 2 functions, executeQuery and executeUpdateQuery (or something equivalent). executeQuery will execute a simple query and return a result set, while executeUpdateQuery will make changes to the DB (insert, update, delete) and return nothing.

Is it accepted to use the first way? It seems unclear to me, but maybe it’s more Pythonistic…? Python is very flexible, maybe I should take advantage of this feature that can’t really be accomplished in this way in more strict languages…

And a second part of this question, unrelated to the main idea – what is the best way to return query results in Python? Using which function to query the database, in what format…?

Answer 1

I don’t know how to answer the first part of your question, it seems like a matter of style more than anything else. Maybe you could invoke the Single Responsibility Principle to argue that it should be two separate functions.

When you’re going to return a sequence of indeterminate length, it’s best to use a Generator.