What are ACID Transactions in Databases

By /

Listen to this Post

Featured Image
ACID (Atomicity, Consistency, Isolation, Durability) transactions ensure reliable database operations. These principles are critical for maintaining data integrity, especially in financial systems, e-commerce, and distributed databases.

You Should Know:

1. Atomicity

Ensures that a transaction is treated as a single unit—either all operations succeed, or none do.

Example (SQL):

BEGIN TRANSACTION; 
UPDATE accounts SET balance = balance - 100 WHERE user_id = 1; 
UPDATE accounts SET balance = balance + 100 WHERE user_id = 2; 
COMMIT; -- If both succeed 
-- OR 
ROLLBACK; -- If any fails

2. Consistency

Guarantees that a transaction brings the database from one valid state to another.

Example (PostgreSQL Check Constraint):

ALTER TABLE accounts ADD CONSTRAINT balance_check CHECK (balance >= 0);

3. Isolation

Ensures concurrent transactions execute as if sequentially.

Isolation Levels in MySQL:

SET TRANSACTION ISOLATION LEVEL READ COMMITTED;

4. Durability

Ensures committed transactions persist even after system failures.

PostgreSQL WAL (Write-Ahead Logging) Command:

pg_waldump /var/lib/postgresql/16/main/pg_wal/000000010000000000000001

Linux Commands for Database Debugging:

 Monitor PostgreSQL logs 
sudo tail -f /var/log/postgresql/postgresql-16-main.log

Check running transactions 
psql -c "SELECT  FROM pg_stat_activity WHERE state = 'active';"

Force kill a stuck transaction 
sudo kill -9 $(ps aux | grep 'postgres: user' | awk '{print $2}')

Windows Commands for SQL Server:

 Check SQL Server transaction logs 
Get-EventLog -LogName "Application" -Source "MSSQLSERVER"

List active transactions 
sqlcmd -Q "DBCC OPENTRAN;"

Expected Output:

A properly executed ACID transaction ensures no partial updates, maintaining database reliability.

Prediction:

As distributed databases grow, ACID compliance will evolve with hybrid models (e.g., Google Spanner’s TrueTime), blending consistency and scalability.

What Undercode Say:

ACID remains foundational, but engineers must balance it with CAP theorem trade-offs. Future databases may integrate AI-driven transaction optimizations.

Expected Output:

-- Successful Transaction 
COMMIT;

URLs:

References:

Reported By: Ashishps1 My – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅

Join Our Cyber World:

💬 Whatsapp | 💬 Telegram

Related Posts: