Understanding ID, and UUID: What’s the Difference?

Abstract

In the world of software development, unique identifiers play a crucial role in managing data efficiently. The terms ID, and UUID often come up in databases, APIs, and distributed systems, but they are not interchangeable. This article explores their differences, use cases, and why UUIDs are sometimes preferred over traditional IDs, using real-world analogies to make understanding them easier.

Introduction

Whenever we store data—whether it's users in a database, orders in an e-commerce system, or posts on a blog—each item needs a unique way to be identified. Traditionally, databases have used IDs (often numeric and sequential), but with the rise of distributed applications and global systems, UUIDs (Universally Unique Identifiers) have become more common. But what exactly are these terms, and when should you use one over the other?

To make it interesting, let’s use an analogy. Imagine you’re at a concert with thousands of people. The event organizers need a way to identify each attendee uniquely. Here’s how UUID and ID work in this situation:

The Concert Analogy: ID vs. UUID

ID: Like a Ticket Number 🎟️

• When you buy a ticket, you get a sequential number (e.g., 001, 002, 003...).
• This is unique within the concert, but if another concert happens, there could be another "Ticket #001" for that event.
• It works perfectly inside a single system (like a database).

UUID: Like a Passport Number 🌍

• A passport is globally unique—no two people in the world have the same passport number.
• Even if you travel to different countries, your passport remains unique everywhere.
• It’s generated in a way that doesn’t rely on order or a central system.
• UUIDs work similarly, ensuring uniqueness across different databases, servers, or even companies.

Breaking Down the Terms: ID, and UUID

ID (Identifier)

• The term ID generally refers to a unique value assigned to an entity.

• Often used in databases as a primary key (e.g., id = 12345).

• Can be numeric, alphanumeric, or even a UUID.

• Example:

  CREATE TABLE users (
      id INT PRIMARY KEY AUTO_INCREMENT,
      name VARCHAR(255)
  );

UUID (Universally Unique Identifier)

• A 128-bit identifier that is designed to be globally unique.

• Represented as a string like: 550e8400-e29b-41d4-a716-446655440000

• Used in distributed systems where uniqueness must be guaranteed across multiple machines.

• Commonly used in NoSQL databases, APIs, and microservices.

• Example:

  CREATE TABLE orders (
      id UUID PRIMARY KEY,
      customer_name VARCHAR(255)
  );

When to Use ID vs. UUID

Best Practices for Choosing the Right Identifier

• Use sequential IDs if your data is confined to a single database and you need fast lookups.
• Use UUIDs if you need unique IDs across multiple systems or databases without conflicts.

Conclusion

Both ID and UUID have their places in software development, and the choice depends on the specific needs of your system. While traditional sequential IDs are easier to manage and index, UUIDs provide the global uniqueness required in distributed applications. By understanding their differences and applying the right one to your use case, you can ensure a more robust and scalable system.

References

• "Universally Unique Identifier" - Wikipedia
• "UUID or SEQUENCE for primary key?" - Stackoverflow