Using Transactions for Synchronized Timestamps

To ensure that two objects have identical database-assigned timestamps, you need to use a database transaction. Here are a few approaches depending on your technology stack:

Using Raw SQL with a Database Connection

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import psycopg2  # For PostgreSQL

# Connect to your database
conn = psycopg2.connect("dbname=yourdb user=youruser password=yourpassword")
try:
    with conn.cursor() as cursor:
        # Start a transaction
        cursor.execute("BEGIN;")
        
        # Update both records with the same timestamp
        cursor.execute("UPDATE accounts SET created_at = CURRENT_TIMESTAMP WHERE id = 1;")
        cursor.execute("UPDATE ledger SET created_at = CURRENT_TIMESTAMP WHERE account_id = 1;")
        
        # Commit the transaction
        cursor.execute("COMMIT;")
except Exception as e:
    conn.rollback()
    print(f"Error: {e}")
finally:
    conn.close()

Using an ORM (like SQLAlchemy)

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from sqlalchemy import create_engine, text
from sqlalchemy.orm import sessionmaker

engine = create_engine('postgresql://youruser:yourpassword@localhost/yourdb')
Session = sessionmaker(bind=engine)
session = Session()

try:
    # Start a transaction
    session.begin()
    
    # Execute the updates
    session.execute(text("UPDATE accounts SET created_at = CURRENT_TIMESTAMP WHERE id = 1"))
    session.execute(text("UPDATE ledger SET created_at = CURRENT_TIMESTAMP WHERE account_id = 1"))
    
    # Commit the transaction
    session.commit()
except Exception as e:
    session.rollback()
    print(f"Error: {e}")
finally:
    session.close()

Using Django ORM

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from django.db import transaction
from django.utils import timezone
from your_app.models import Account, Ledger

# Get the current time to use for both objects
now = timezone.now()

with transaction.atomic():
    account = Account.objects.get(id=1)
    ledger = Ledger.objects.get(account_id=1)
    
    account.created_at = now
    ledger.created_at = now
    
    account.save()
    ledger.save()

The key is to use a transaction to ensure both updates are processed together, and to use the same timestamp value for both records.