How to Demonstrate the Shared Database Antipattern in Python

import sqlite3
from pathlib import Path

def create_shared_db(db_path: Path) -> None:
    """Mock demonstrating the shared database antipattern where multiple
    services access the same database, causing tight coupling."""
    conn = sqlite3.connect(db_path)
    cur = conn.cursor()
    cur.execute("""
        CREATE TABLE IF NOT EXISTS users (
            id INTEGER PRIMARY KEY,
            name TEXT NOT NULL,
            service TEXT NOT NULL
        )
    """)
    conn.commit()
    conn.close()


def add_user(db_path: Path, name: str, service: str) -> None:
    conn = sqlite3.connect(db_path)
    cur = conn.cursor()
    cur.execute("INSERT INTO users (name, service) VALUES (?, ?)", (name, service))
    conn.commit()
    conn.close()


def list_users(db_path: Path) -> list:
    conn = sqlite3.connect(db_path)
    cur = conn.cursor()
    rows = cur.execute("SELECT id, name, service FROM users ORDER BY id").fetchall()
    conn.close()
    return [{"id": r[0], "name": r[1], "service": r[2]} for r in rows]


if __name__ == "__main__":
    db = Path("mock_shared.sqlite3")
    if db.exists():
        db.unlink()
    create_shared_db(db)
    add_user(db, "Alice", "auth-service")
    add_user(db, "Bob", "billing-service")
    add_user(db, "Carol", "auth-service")
    for user in list_users(db):
        print(f"ID={user['id']}, Name={user['name']}, Service={user['service']}")
    db.unlink()