如何Generate UUIDs
Create universally 唯一 identifiers (UUIDs/GUIDs) 在 various versions.
问题
你 need 唯一 identifier 为记录, 会话, 或事件该 是 guaranteed 唯一无 中心 coordination.
前置条件
- Understanding 的唯一 identifiers
- Knowledge 的 UUID versions
步骤
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1. Choose the UUID version
Version 4 (random) is the most common — it uses random bits and has an extremely low collision probability. Version 7 is time-ordered, useful for databases. Version 5 is deterministic (name-based with SHA-1). Version 1 is time-based with a node ID.
输入version: 4 (random)输出version selected -
2. Generate the UUID
Generate a UUID of the chosen version. A v4 UUID has the format xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx where y is 8, 9, a, or b. The generation uses a cryptographically secure RNG for v4. The output is a 36-character string with hyphens.
输入generate v4输出550e8400-e29b-41d4-a716-446655440000 -
3. Use and store the UUID
Use the UUID as a unique key for database records, session IDs, or event identifiers. UUIDs are 128 bits, providing sufficient uniqueness for virtually all applications. Store as a UUID type in databases (more efficient than string) or as a 36-character string.
输入UUID for database record输出unique key assigned
预期结果
有效 UUID 在 specified version, 具有正确格式化和 version bits.
常见错误
- Using Math.random for UUID generation
- Math.random is not cryptographically secure. Use crypto.randomUUID() or a CSPRNG for v4 UUIDs to ensure unpredictability.
- UUID stored as VARCHAR(36) when a native type exists
- Many databases have a native UUID type that is more efficient (16 bytes vs 37 characters) and indexed faster. Use the native type when available.
排障指引
- If UUIDs collide (extremely unlikely for v4), verify the RNG is working correctly.
- For time-ordered UUIDs (v7), ensure the clock is monotonic to avoid ordering issues.
安全限制
- UUID v4 values are unpredictable and suitable for session tokens. However, they are not cryptographically strong — use a dedicated token generator for security-critical purposes.
- All generation is local.