Question 1

What is a UUID?

Accepted Answer

A Universally Unique Identifier — a 128-bit number formatted as 32 hex digits in 5 groups (e.g., 550e8400-e29b-41d4-a716-446655440000).

Question 2

What version does this generate?

Accepted Answer

UUID v4 (random), which uses cryptographic randomness. The probability of collision is astronomically low.

Question 3

Can I use UUIDs as database primary keys?

Accepted Answer

Yes — UUIDs are commonly used in distributed systems where auto-increment IDs aren't practical.

Question 4

Are they truly unique?

Accepted Answer

Statistically yes. With 2^122 possible v4 UUIDs, you'd need to generate 1 billion per second for 86 years to have a 50% chance of one collision.

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