Understand the architecture of the PostgreSQL database.

# Understanding PostgreSQL Internals

## Core Concepts

hello

PostgreSQL solves four main problems:

1. Concurrency - Handle multiple users

2. Persistence - Store data safely

3. Consistency - Maintain data integrity

4. Durability - Survive crashes

### Code Example

```sql

-- Transaction example

BEGIN;

UPDATE accounts SET balance = balance - 100 WHERE id = 1;

UPDATE accounts SET balance = balance + 100 WHERE id = 2;

COMMIT;