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System design patterns

Sharding, load balancing, CAP tradeoffs, and scaling patterns — interview and production ready.

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How to Implement CQRS with Separate Read and Write Models in Python

Implements Command Query Responsibility Segregation (CQRS) by splitting data into separate write and read models with dedicated repositories, using dataclasses for structure.

cqrs dataclasses repositories

Python

from dataclasses import dataclass, field
from typing import List, Dict, Optional


@dataclass
class OrderWriteModel:
    order_id: int
    customer: str
    items: List[str] = field(default_factory=list)

    def add_item(self, item: str) -> None:
        self.items.append(item)


@dataclass
class OrderReadModel:
    …

14 0 Open

System design patterns easy

How to Implement a Data Helper Class in Python

Build a beginner-friendly DataHelper class using dataclasses and key system design patterns like Command, Strategy, and Map.

dataclass data-helper design-patterns

Python

from __future__ import annotations
from dataclasses import dataclass, field
from typing import Any, Dict, List, Optional


@dataclass
class DataHelper:
    """A beginner-friendly data utility with common system design patterns."""
    data: List[Dict[str, Any]] = field(default_factory=list)

    def add_record(self, r…

13 0 Open

System design patterns medium

How to Implement a Simple MVVM Binding Mock in Python

A minimal Python implementation of the MVVM pattern, mocking data binding so views auto-update when the view model changes.

mvvm binding observer pattern

Python

class BindingMock:
    def __init__(self, view_model):
        self.view_model = view_model
        self.subscribers = []

    def bind(self, property_name, callback):
        self.subscribers.append((property_name, callback))

    def set(self, property_name, value):
        setattr(self.view_model, property_name, va…

18 0 Open

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