I am working on using mysql.connector in a class and have found an example of how to create a single connection that spans the lifetime of all instances of the class:
https://softwareengineering.stackexchange.com/a/358061/317228 however, I do not understand a few things about the class, including 1. Why it is subclassed as an object: `class Postgres(object):` ? I thought classes were necessarily objects. 2. Why is this portion of code directly addressing the class, instead of using the `cls` reference variable? connection = Postgres._instance.connection = psycopg2.connect(**db_config) cursor = Postgres._instance.cursor = connection.cursor() 3. And is it me or does anyone else think {anydb}.connector’s usage is messy and inelegant? Ex: print('connecting to PostgreSQL database...') connection = Postgres._instance.connection = psycopg2.connect(**db_config) cursor = Postgres._instance.cursor = connection.cursor() cursor.execute('SELECT VERSION()') db_version = cursor.fetchone() Why can’t we associate the focus of the connection with the connection itself, instead of creating a separate cursor object? Also, within the code example, and in Python in general, why does there needs to be a __new__ constructor when there’s an __init__ constructor? I’ve read about the usage of singletons. It seems you could create singletons within __init__ or __new__ . Any enlightenment would be really helpful. I am very sleep-deprived, so I’m sorry if this seems like a dumb question. I have read the official docs. Have also been reading “Python 3: Patterns, Recipes, and Idioms”. The first was mildly helpful but I still don’t see the benefit of a __new__ constructor. Why is there dislike for Metaclasses? Thanks, and I’ll have better incisive questions in the future. Sent from Mail for Windows 10 -- https://mail.python.org/mailman/listinfo/python-list
