All Questions
Tagged with python design-patterns
132 questions
1
vote
1
answer
314
views
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
4
votes
2
answers
459
views
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
1
vote
3
answers
988
views
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
2
votes
1
answer
131
views
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
-2
votes
2
answers
1k
views
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:
...
- 1
1
vote
2
answers
107
views
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
2
votes
2
answers
562
views
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
2
votes
1
answer
247
views
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
2
votes
1
answer
261
views
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
-1
votes
1
answer
218
views
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
5
votes
1
answer
12k
views
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
0
votes
1
answer
239
views
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
0
votes
1
answer
474
views
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 ...
- 447
0
votes
0
answers
133
views
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:...
- 113
1
vote
1
answer
463
views
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