All Questions
Tagged with design-patternspython
132 questions
1vote
1answer
314views
Where to create repository instances?
I've several repositories. To make them testable, I add the ORM session in the constructor. class Repository: def __init__(session): self.session = session def save(object): self.session()...
CommunityBot
- 1
4votes
2answers
459views
Data processing pipeline design for processing data
I have a use case for which I need to build a data processing pipeline Customer contact leads data coming from different data sources like csv, data base, api has to be first mapped to a universal ...
CommunityBot
- 1
1vote
3answers
986views
Storing multiple instances on a Singleton?
RefactoringGuru's example Singleton in Python has an _instances dictionary field class Singleton(type): _instances = {} def __call__(cls, *args, **kwargs): if cls not in cls....
- 48.8k
2votes
1answer
131views
A Design Pattern for a component which both writes to and reads from an ordered event log
I am searching for a good design for a set of components I am writing for a system. I believe it is very likely there is a Design Pattern, or set of Design Patterns, which could be combined to solve ...
- 320
-2votes
2answers
1kviews
Best practice: keep DB models in one file or split into modules?
I've a Python project with ~30 SQLAlchemy models and I'm not sure where they belong. All models belong to the DB but also to a module, so I'm not sure about the right namespace. Here are some ideas: ...
1vote
2answers
107views
Dynamic web application hitting database on front page load to fetch profile image
Folks, I am in middle of writing a web application (Python/Flask) where home page has user profile image in the navbar which is coming from a database (blob), I am wondering if this is a good practice....
- 11.7k
2votes
2answers
562views
Is this architecture overkill? What is a good way to architect this software?
I have an algorithm I am trying to implement that has steps 1 to 5. There are several different ways I could implement each step. Each calculation step is essentially just an astronomy calculation, ...
- 218k
2votes
1answer
247views
How do I structure my functions (and classes?) which interact with my Database/ORM?
So I am working on my first project using SQLite and SQLModel as ORM. Creating and handling the first table in my database was easily structured: A function for each CRUD-Operation. But now I have ...
- 251
2votes
1answer
260views
Design patterns for long chains of computations in python (functions vs classes?)
A recurring pattern which I see in my code is chaining together a lot of functions. This is the result of a large number of processing steps needed for a given task. This could be e.g. a data ...
- 7,635
-1votes
1answer
218views
How can I use builders for products with incompatible interfaces?
I am working on a program to automatically design heater units based on varying client specifications. The process for creating each heater is quite involved and requires multiple optional steps ...
CommunityBot
- 1
5votes
1answer
12kviews
Using singletons in Python (Django)
I was suggested to define a singleton in Python in the following way: class Controller: pass # ... controller = Controller() However, this way, controller cannot be replaced with a derived ...
- 6,003
0votes
1answer
239views
How do we nest decorators?
It is possible to nest many decorators. @decorator_one @decorator_two @decorator_three @decorator_four def some_silly_function(): pass How do we write a decorator class so that the order in which ...
- 1,353
0votes
1answer
474views
Multiple models/controllers python app
I am trying to tinker with the MVC pattern and I have a problem when trying to design the MVC structure. I need a model for products, however as I need to manage more and different data, I can help ...
0votes
0answers
133views
Python Typechecking versus TypedDicts?
From what I understand from this answer, it is not possible to use a typeddict and typechecking in a function. So for example, if one has a function: def some_func(some_int: int, some_dict:...
1vote
1answer
463views
What is an apporpriate design pattern when dealing with Pandas and databases?
We're dealing with a lot of "data analysis", basically different sorts of data mangling, aggregations and calculations using Pandas. Usually, the data is time series data. All underlying ...
- 218k
