UUID Generator

// Browser + Node 19+ (built-in, v4)
const id = crypto.randomUUID();
console.log(id);             // 550e8400-e29b-41d4-a716-446655440000

// Node.js (via the crypto module)
import { randomUUID } from "node:crypto";
console.log(randomUUID());

// Uppercase / no hyphens
console.log(id.toUpperCase());
console.log(id.replace(/-/g, ""));

import java.util.UUID;

// v4 (random)
UUID id = UUID.randomUUID();
System.out.println(id);      // 550e8400-e29b-41d4-a716-446655440000

// v3 (name-based, MD5)
UUID named = UUID.nameUUIDFromBytes("example.com".getBytes());
System.out.println(named);

// Parse from text
UUID parsed = UUID.fromString("550e8400-e29b-41d4-a716-446655440000");

using System;

// v4-like GUID (random)
Guid id = Guid.NewGuid();
Console.WriteLine(id);              // 550e8400-e29b-41d4-a716-446655440000
Console.WriteLine(id.ToString("B")); // {550e8400-...} .NET GUID format
Console.WriteLine(id.ToString("N")); // no hyphens
Console.WriteLine(id.ToString("D").ToUpper()); // uppercase

// .NET 9+: v7 (time-ordered, database-friendly)
Guid v7 = Guid.CreateVersion7();

package main

import (
    "fmt"

    "github.com/google/uuid"
)

func main() {
    fmt.Println(uuid.New())     // v4 (random)

    // v5 (name-based, SHA-1)
    fmt.Println(uuid.NewSHA1(uuid.NameSpaceDNS, []byte("example.com")))

    // v7 (time-ordered) — google/uuid v1.6+
    v7, _ := uuid.NewV7()
    fmt.Println(v7)
}

use Ramsey\Uuid\Uuid;

// v4 (random)
echo Uuid::uuid4()->toString();   // 550e8400-e29b-41d4-a716-446655440000

// v7 (time-ordered, database-friendly)
echo Uuid::uuid7()->toString();

// v5 (name-based, SHA-1) — deterministic
echo Uuid::uuid5(Uuid::NAMESPACE_DNS, "example.com")->toString();

-- Generate a v4 (random) UUID
SELECT gen_random_uuid();

-- Automatic default on a table column
CREATE TABLE users (
  id    uuid PRIMARY KEY DEFAULT gen_random_uuid(),
  name  text NOT NULL
);

-- Older versions (PostgreSQL 12 and earlier):
-- CREATE EXTENSION IF NOT EXISTS pgcrypto;

-- Generate a text UUID (v1-based)
SELECT UUID();

-- Store as a sorted 16-byte BINARY (index-friendly)
SELECT UUID_TO_BIN(UUID(), 1);

CREATE TABLE users (
  id    BINARY(16) PRIMARY KEY,
  name  VARCHAR(120) NOT NULL
);

-- Convert back to text when reading:
-- SELECT BIN_TO_UUID(id, 1) FROM users;