Recently, I went through the exercise of converting my e-commerce platform’s database and application to using UUIDs (Universally Unique Identifiers) over auto-increment fields as a way to modernize and scale after a long pause on development. Here were some of the reasons:

1. Global Uniqueness: UUIDs are designed to be globally unique, even across different systems and databases. This eliminates the possibility of clashes between identifiers, making it suitable for distributed and decentralized systems where auto-increment values might not be guaranteed unique across multiple instances.
2. Decentralization: In distributed systems or microservices architectures, generating unique auto-increment values across multiple nodes or services can be challenging. UUIDs provide a way to generate identifiers without the need for centralized coordination, making them more suitable for decentralized and cloud-based applications.
3. No Dependency on Database State: Auto-increment fields require a centralized source, the database, to generate unique values. This can become a bottleneck as the application scales, and it can lead to contention in high-concurrency scenarios. UUIDs can be generated by the application itself without relying on the database, reducing this potential source of contention.
4. Data Merging and Synchronization: When different databases or instances need to be merged or synchronized, auto-increment values can clash and lead to conflicts. UUIDs guarantee uniqueness, simplifying data merging processes and ensuring a smooth synchronization across different systems.
5. Security and Privacy: Auto-increment values can sometimes expose information about the order of data creation or other patterns, which might not be desirable for security or privacy reasons. UUIDs, being random and complex, provide an extra layer of obfuscation in this regard.
6. Compatibility with Offline and Batch Operations: In scenarios where data is collected offline or in batch processes and then synchronized with the main database, UUIDs allow for locally generated identifiers that won’t clash with those generated in the online system.
7. Compatibility with Different Databases: UUIDs can be used across various types of databases, both SQL and NoSQL, without worrying about different mechanisms for generating auto-increment values. This provides greater flexibility and eases the process of switching or integrating with different database systems.
8. Future-Proofing: UUIDs are designed to be a long-term solution, even as systems evolve and change. Auto-increment values might face limitations or challenges as the system grows, but UUIDs provide a more stable identifier solution.

However, the currently underlying database cannot currently natively handle UUIDs as types, so there will be a larger storage footprint (compared to integers), potentially slower indexing performance, and decreased human readability in some cases.

The choice between UUIDs and auto-increment fields should be made based on the specific requirements and characteristics of the application, taking into account factors like data distribution, scalability, and performance.

Java

import java.util.UUID;

public class UUIDGenerator {
  public static void main(String[] args) {
    UUID uuid = UUID.randomUUID();
    System.out.println("Generated UUID V4: " + uuid.toString());
  }
}

PHP

function generateUUIDV4() {
  $data = openssl_random_pseudo_bytes(16);
  $data[6] = chr(ord($data[6]) & 0x0f | 0x40); 
  $data[8] = chr(ord($data[8]) & 0x3f | 0x80);
  $uuid = vsprintf('%s%s-%s-%s-%s-%s%s%s', str_split(bin2hex($data), 4));
  return $uuid;
}

$uuidV4 = generateUUIDV4();
echo "Generated UUID V4: " . $uuidV4 . PHP_EOL;