How to Bulk Generate UUIDs

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How to Bulk Generate UUIDs

· 5 min read

Common Scenarios for Bulk UUID Generation

Typical scenarios requiring bulk UUID generation: database seed data initialization (pre-preparing unique IDs for large numbers of records rather than having the database generate them at insert time); test data generation (preparing a fixed UUID set for automated tests to make tests deterministic); data migration (batch-assigning new UUIDs to records migrated from old systems); API key or token candidate pools (bulk pre-generating backup unique identifiers); batch naming of documents or assets (assigning unique names to a batch of uploaded files).

Command-Line Bulk Generation

# Linux/macOS：生成 100 个 UUID
for i in $(seq 1 100); do uuidgen; done

# macOS 默认大写，转小写
for i in $(seq 1 100); do uuidgen | tr '[:upper:]' '[:lower:]'; done

# 保存到文件
for i in $(seq 1 1000); do uuidgen; done > uuids.txt

# Python 一行命令批量生成
python3 -c "import uuid; [print(uuid.uuid4()) for _ in range(100)]"

# 生成 CSV 格式（带索引）
python3 -c "
import uuid
print('index,uuid')
for i in range(1, 101):
    print(f'{i},{uuid.uuid4()}')
" > uuids.csv

# Node.js 批量生成
node -e "
const {randomUUID} = require('crypto');
for(let i=0;i randomUUID());
}

// 生成 JSON 文件（适合作为测试数据）
function generateTestData(count) {
  const data = Array.from({ length: count }, (_, i) => ({
    id: randomUUID(),
    name: `Test Item ${i + 1}`,
    createdAt: new Date().toISOString(),
  }));
  return JSON.stringify(data, null, 2);
}

// 保存到文件
fs.writeFileSync('test-data.json', generateTestData(100));
console.log('Generated 100 test records with UUIDs');

// 生成 CSV 格式
function generateCSV(count) {
  const header = 'id,name,status';
  const rows = Array.from({ length: count }, (_, i) =>
    `${randomUUID()},Item ${i + 1},active`
  );
  return [header, ...rows].join('\n');
}

fs.writeFileSync('test-data.csv', generateCSV(500));

Database-Level Bulk Generation

-- PostgreSQL：批量生成 UUID 记录
INSERT INTO products (id, name, category)
SELECT gen_random_uuid(), 'Product ' || gs, 'default'
FROM generate_series(1, 1000) AS gs;

-- MySQL 8.0+：批量插入
DELIMITER //
CREATE PROCEDURE bulk_insert_uuids(IN count INT)
BEGIN
  DECLARE i INT DEFAULT 0;
  WHILE i < count DO
    INSERT INTO items (id, name) VALUES (UUID(), CONCAT('Item ', i));
    SET i = i + 1;
  END WHILE;
END //
DELIMITER ;
CALL bulk_insert_uuids(1000);

-- SQL Server：批量生成
INSERT INTO orders (id, status)
SELECT NEWID(), 'pending'
FROM (
  SELECT TOP 1000 ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) AS n
  FROM sys.objects CROSS JOIN sys.objects
) AS nums;

Considerations for Bulk Generation

Things to note when bulk generating UUIDs: each UUID is independently generated with no correlation between them — bulk generation does not increase collision risk; do not use loops calling non-cryptographically-secure random number generators like Math.random(); if bulk-generated UUIDs will be used in databases, consider batch inserts (rather than row-by-row inserts) for better performance; for extremely large batches (over one million), consider processing in chunks and writing to files to avoid memory overflow; if you need reproducible test data (same UUIDs generated each run), use UUID v5 derived from indexes or names rather than random v4.

Verifying Uniqueness of Bulk Generation Results

import uuid

# 生成并验证唯一性（用于演示，生产中无需这样做）
def bulk_generate_verified(count):
    uuids = set()
    while len(uuids) < count:
        new_uuid = str(uuid.uuid4())
        uuids.add(new_uuid)
    return list(uuids)

# 统计 set 大小等于 list 大小说明无重复
uuids = [str(uuid.uuid4()) for _ in range(100000)]
unique_count = len(set(uuids))
print(f"Generated: {len(uuids)}, Unique: {unique_count}")
# 几乎必然输出：Generated: 100000, Unique: 100000

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