حدود القاعدة ووحدة العمل

import sqlite3
connection = sqlite3.connect(":memory:")
try:
    connection.execute("CREATE TABLE account (id INTEGER PRIMARY KEY, balance INTEGER NOT NULL)")
    with connection:
        connection.execute("INSERT INTO account VALUES (?, ?)", (1, 10))
    try:
        with connection:
            connection.execute("UPDATE account SET balance = ? WHERE id = ?", (7, 1))
            connection.execute("INSERT INTO account VALUES (?, ?)", (1, 2))
    except sqlite3.IntegrityError:
        pass
    print(connection.execute("SELECT balance FROM account WHERE id = ?", (1,)).fetchone()[0])
finally:
    connection.close()

10

يلغي المفتاح المكرر المعاملة ويبقى 10 بقاعدة خاصة بالذاكرة لا مشروع أوإثبات عزل عام.

from typing import Annotated
from fastapi import Depends, FastAPI, HTTPException
from fastapi.testclient import TestClient
def repository(): return {1: {"id": 1, "name": "pen"}}
app = FastAPI()
@app.get("/items/{item_id}")
def item(item_id: int, rows: Annotated[dict, Depends(repository)]):
    if item_id not in rows: raise HTTPException(status_code=404, detail="Missing")
    return rows[item_id]
with TestClient(app) as client:
    print(client.get("/items/1").json())
    app.dependency_overrides[repository] = lambda: {}
    try:
        print(client.get("/items/1").status_code)
    finally:
        app.dependency_overrides.clear()

{'id': 1, 'name': 'pen'}
404

يرى المسار مستودعا مضبوطا ثم غيابا؛ والقاموس تجهيز لا حفظا دائما أوخدمة.