{"id":532,"date":"2024-12-25T23:48:34","date_gmt":"2024-12-25T15:48:34","guid":{"rendered":"https:\/\/www.laixuexila.com\/?p=532"},"modified":"2024-12-25T23:48:34","modified_gmt":"2024-12-25T15:48:34","slug":"js%e6%95%b0%e6%8d%ae%e5%ba%93%e6%80%a7%e8%83%bd%e4%bc%98%e5%8c%96%e7%9a%84%e7%ad%96%e7%95%a5%e6%9c%89%e5%93%aa%e4%ba%9b%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/www.laixuexila.com\/index.php\/2024\/12\/25\/js%e6%95%b0%e6%8d%ae%e5%ba%93%e6%80%a7%e8%83%bd%e4%bc%98%e5%8c%96%e7%9a%84%e7%ad%96%e7%95%a5%e6%9c%89%e5%93%aa%e4%ba%9b%ef%bc%9f\/","title":{"rendered":"js\u6570\u636e\u5e93\u6027\u80fd\u4f18\u5316\u7684\u7b56\u7565\u6709\u54ea\u4e9b\uff1f"},"content":{"rendered":"\n
\n

\u5728 JavaScript \u5e94\u7528\u4e2d\u4e0e\u6570\u636e\u5e93\u4ea4\u4e92\u65f6\uff0c\u6027\u80fd\u4f18\u5316\u4e3b\u8981\u4f53\u73b0\u5728\u51cf\u5c11\u67e5\u8be2\u65f6\u95f4\u3001\u964d\u4f4e\u7f51\u7edc\u5ef6\u8fdf\u548c\u63d0\u9ad8\u6570\u636e\u64cd\u4f5c\u7684\u6548\u7387\u3002\u4ee5\u4e0b\u662f\u5e38\u89c1\u7684\u4f18\u5316\u7b56\u7565\uff1a<\/p>\n<\/blockquote>\n\n\n\n

\n\n\n\n

1. \u4f18\u5316\u67e5\u8be2<\/strong><\/h3>\n\n\n\n

1.1. \u4f7f\u7528\u7d22\u5f15<\/strong><\/h4>\n\n\n\n
    \n
  • \u7d22\u5f15\u53ef\u4ee5\u5927\u5e45\u63d0\u9ad8\u67e5\u8be2\u6027\u80fd\uff0c\u5c24\u5176\u662f\u9891\u7e41\u67e5\u8be2\u7684\u5b57\u6bb5\u3002<\/li>\n\n\n\n
  • \u786e\u4fdd\u5728\u8fc7\u6ee4\u6761\u4ef6\u3001\u6392\u5e8f\u5b57\u6bb5\u4e0a\u5efa\u7acb\u9002\u5f53\u7684\u7d22\u5f15\u3002<\/li>\n<\/ul>\n\n\n\n

    \u793a\u4f8b\uff08SQL\uff09\uff1a<\/strong><\/p>\n\n\n\n

    CREATE INDEX idx_users_email ON users(email);<\/code><\/pre>\n\n\n\n
    MongoDB \u793a\u4f8b\uff1a<\/strong><\/p>\n\n\n\n
    db.users.createIndex({ email: 1 });<\/code><\/pre>\n\n\n\n
    1.2. \u907f\u514d\u5168\u8868\u626b\u63cf<\/strong><\/h4>\n\n\n\n
      \n
    • \u67e5\u8be2\u65f6\u5c3d\u91cf\u4f7f\u7528\u6761\u4ef6\u8fc7\u6ee4\uff08WHERE<\/code> \u5b50\u53e5\uff09\u3002<\/li>\n\n\n\n
    • \u907f\u514d\u5728\u67e5\u8be2\u6761\u4ef6\u4e2d\u5bf9\u5b57\u6bb5\u8fdb\u884c\u8ba1\u7b97\u6216\u51fd\u6570\u8c03\u7528\u3002<\/li>\n<\/ul>\n\n\n\n
      \u975e\u63a8\u8350\uff1a<\/strong><\/p>\n\n\n\n
      SELECT * FROM users WHERE YEAR(created_at) = 2022;<\/code><\/pre>\n\n\n\n
      \u63a8\u8350\uff1a<\/strong><\/p>\n\n\n\n
      SELECT * FROM users WHERE created_at >= '2022-01-01' AND created_at < '2023-01-01';<\/code><\/pre>\n\n\n\n
      1.3. \u9650\u5236\u8fd4\u56de\u7684\u6570\u636e\u91cf<\/strong><\/h4>\n\n\n\n
        \n
      • \u4f7f\u7528\u5206\u9875\uff08LIMIT<\/code> \u548c OFFSET<\/code>\uff09\u51cf\u5c11\u4e00\u6b21\u67e5\u8be2\u8fd4\u56de\u7684\u8bb0\u5f55\u6570\u3002<\/li>\n\n\n\n
      • \u4ec5\u67e5\u8be2\u9700\u8981\u7684\u5b57\u6bb5\uff0c\u800c\u4e0d\u662f\u4f7f\u7528 SELECT *<\/code>\u3002<\/li>\n<\/ul>\n\n\n\n
        SQL \u793a\u4f8b\uff1a<\/strong><\/p>\n\n\n\n
        SELECT id, name, email FROM users LIMIT 10 OFFSET 0;<\/code><\/pre>\n\n\n\n
        MongoDB \u793a\u4f8b\uff1a<\/strong><\/p>\n\n\n\n
        db.users.find({}, { name: 1, email: 1 }).limit(10).skip(0);<\/code><\/pre>\n\n\n\n
        \n\n\n\n
        2. \u51cf\u5c11\u7f51\u7edc\u5ef6\u8fdf<\/strong><\/h3>\n\n\n\n
        2.1. \u6279\u91cf\u64cd\u4f5c<\/strong><\/h4>\n\n\n\n
          \n
        • \u907f\u514d\u9891\u7e41\u53d1\u9001\u5c0f\u67e5\u8be2\uff0c\u6539\u4e3a\u6279\u91cf\u5904\u7406\u3002<\/li>\n<\/ul>\n\n\n\n
          \u793a\u4f8b\uff1a\u6279\u91cf\u63d2\u5165<\/strong><\/p>\n\n\n\n
          \/\/ MySQL\nINSERT INTO users (name, email) VALUES ('Alice', 'alice@example.com'), ('Bob', 'bob@example.com');\n\n\/\/ MongoDB\ndb.users.insertMany([\n  { name: 'Alice', email: 'alice@example.com' },\n  { name: 'Bob', email: 'bob@example.com' }\n]);<\/code><\/pre>\n\n\n\n
          2.2. \u7f13\u5b58\u7ed3\u679c<\/strong><\/h4>\n\n\n\n
            \n
          • \u5bf9\u9891\u7e41\u67e5\u8be2\u4f46\u4e0d\u5e38\u66f4\u65b0\u7684\u6570\u636e\u4f7f\u7528\u7f13\u5b58\u673a\u5236\u3002<\/li>\n\n\n\n
          • \u4f7f\u7528 Redis\u3001Memcached \u6216\u5185\u5b58\u7f13\u5b58\uff08\u5982 node-cache<\/code>\uff09\u3002<\/li>\n<\/ul>\n\n\n\n
            \u793a\u4f8b\uff1a\u4f7f\u7528 Redis \u7f13\u5b58<\/strong><\/p>\n\n\n\n
            const redis = require('redis');\nconst client = redis.createClient();\n\n\/\/ \u67e5\u8be2\u6570\u636e\u5e76\u7f13\u5b58\nasync function getCachedData(key, fetchFn) {\n  const cached = await client.get(key);\n  if (cached) return JSON.parse(cached);\n\n  const freshData = await fetchFn();\n  client.setex(key, 3600, JSON.stringify(freshData)); \/\/ \u7f13\u5b581\u5c0f\u65f6\n  return freshData;\n}<\/code><\/pre>\n\n\n\n
            \n\n\n\n
            3. \u4f7f\u7528\u5f02\u6b65\u4e0e\u5e76\u884c<\/strong><\/h3>\n\n\n\n
            JavaScript \u7684\u975e\u963b\u585e I\/O \u6a21\u578b\u9002\u5408\u5904\u7406\u6570\u636e\u5e93\u4f18\u5316\uff1a<\/p>\n\n\n\n
              \n
            • \u4f7f\u7528 Promise.all<\/code> \u6216\u7c7b\u4f3c\u5de5\u5177\u5e76\u884c\u6267\u884c\u591a\u6b21\u67e5\u8be2\u3002<\/li>\n\n\n\n
            • \u5c3d\u91cf\u907f\u514d\u540c\u6b65\u64cd\u4f5c\u3002<\/li>\n<\/ul>\n\n\n\n
              \u793a\u4f8b\uff1a\u5e76\u884c\u67e5\u8be2<\/strong><\/p>\n\n\n\n
              const [users, orders] = await Promise.all([\n  db.query('SELECT * FROM users'),\n  db.query('SELECT * FROM orders')\n]);<\/code><\/pre>\n\n\n\n
              \n\n\n\n
              4. \u51cf\u5c11\u6570\u636e\u64cd\u4f5c\u7684\u590d\u6742\u5ea6<\/strong><\/h3>\n\n\n\n
              4.1. \u5229\u7528\u6570\u636e\u5e93\u7684\u805a\u5408\u529f\u80fd<\/strong><\/h4>\n\n\n\n
                \n
              • \u5c06\u590d\u6742\u7684\u8ba1\u7b97\u548c\u805a\u5408\u4ea4\u7531\u6570\u636e\u5e93\u5b8c\u6210\uff0c\u800c\u4e0d\u662f\u5728\u524d\u7aef\u8fdb\u884c\u3002<\/li>\n<\/ul>\n\n\n\n
                SQL \u793a\u4f8b\uff1a<\/strong><\/p>\n\n\n\n
                SELECT COUNT(*), AVG(age) FROM users WHERE age > 18;<\/code><\/pre>\n\n\n\n
                MongoDB \u793a\u4f8b\uff1a<\/strong><\/p>\n\n\n\n
                db.users.aggregate([\n  { $match: { age: { $gt: 18 } } },\n  { $group: { _id: null, count: { $sum: 1 }, avgAge: { $avg: '$age' } } }\n]);<\/code><\/pre>\n\n\n\n
                4.2. \u907f\u514d N+1 \u67e5\u8be2\u95ee\u9898<\/strong><\/h4>\n\n\n\n
                  \n
                • \u5728\u4e00\u4e2a\u67e5\u8be2\u4e2d\u83b7\u53d6\u6240\u9700\u7684\u6240\u6709\u76f8\u5173\u6570\u636e\uff0c\u907f\u514d\u591a\u6b21\u67e5\u8be2\u3002<\/li>\n<\/ul>\n\n\n\n
                  \u63a8\u8350\uff1aJOIN<\/strong><\/p>\n\n\n\n
                  SELECT users.name, orders.total \nFROM users \nJOIN orders ON users.id = orders.user_id;<\/code><\/pre>\n\n\n\n
                  MongoDB \u793a\u4f8b\uff1a$lookup<\/code><\/strong><\/p>\n\n\n\n
                  db.users.aggregate([\n  {\n    $lookup: {\n      from: 'orders',\n      localField: '_id',\n      foreignField: 'user_id',\n      as: 'userOrders'\n    }\n  }\n]);<\/code><\/pre>\n\n\n\n
                  \n\n\n\n
                  5. \u524d\u7aef\u6570\u636e\u5904\u7406\u4f18\u5316<\/strong><\/h3>\n\n\n\n
                    \n
                  • \u4f7f\u7528\u6570\u636e\u865a\u62df\u5316\uff08Virtualization\uff09\uff1a\u4ec5\u52a0\u8f7d\u7528\u6237\u53ef\u89c1\u7684\u6570\u636e\u3002<\/li>\n\n\n\n
                  • \u4f7f\u7528\u5206\u9875\u3001\u61d2\u52a0\u8f7d\u548c\u641c\u7d22\u5efa\u8bae\u529f\u80fd\u3002<\/li>\n\n\n\n
                  • \u4f7f\u7528 Web Worker \u5904\u7406\u5927\u91cf\u6570\u636e\uff0c\u907f\u514d\u4e3b\u7ebf\u7a0b\u963b\u585e\u3002<\/li>\n<\/ul>\n\n\n\n
                    \n\n\n\n
                    6. \u6570\u636e\u5e93\u8fde\u63a5\u6c60<\/strong><\/h3>\n\n\n\n
                    \u4f7f\u7528\u8fde\u63a5\u6c60\u590d\u7528\u6570\u636e\u5e93\u8fde\u63a5\uff0c\u51cf\u5c11\u8fde\u63a5\u5efa\u7acb\u7684\u5f00\u9500\uff1a<\/p>\n\n\n\n
                      \n
                    • MySQL \u793a\u4f8b\uff1a<\/strong><\/li>\n<\/ul>\n\n\n\n
                      const mysql = require('mysql2');\nconst pool = mysql.createPool({\n  host: 'localhost',\n  user: 'root',\n  password: 'password',\n  database: 'mydb',\n  waitForConnections: true,\n  connectionLimit: 10,\n  queueLimit: 0\n});<\/code><\/pre>\n\n\n\n
                        \n
                      • MongoDB \u793a\u4f8b\uff1a<\/strong><\/li>\n<\/ul>\n\n\n\n
                        const { MongoClient } = require('mongodb');\nconst client = new MongoClient('mongodb:\/\/localhost:27017', {\n  poolSize: 10\n});<\/code><\/pre>\n\n\n\n
                        \n\n\n\n
                        7. \u5b9a\u671f\u7ef4\u62a4\u4e0e\u76d1\u63a7<\/strong><\/h3>\n\n\n\n
                          \n
                        • \u5b9a\u671f\u5206\u6790\u6162\u67e5\u8be2\u65e5\u5fd7\uff0c\u4f18\u5316\u67e5\u8be2\u6027\u80fd\u3002<\/li>\n\n\n\n
                        • \u5b9a\u671f\u91cd\u5efa\u548c\u7ef4\u62a4\u7d22\u5f15\u3002<\/li>\n\n\n\n
                        • \u76d1\u63a7\u6570\u636e\u5e93\u6027\u80fd\uff08\u5982\u4f7f\u7528 PM2\u3001New Relic\uff09\u3002<\/li>\n<\/ul>\n\n\n\n
                          \n\n\n\n
                          8. \u5206\u7247\u4e0e\u5206\u533a<\/strong><\/h3>\n\n\n\n
                            \n
                          • \u5bf9\u4e8e\u8d85\u5927\u6570\u636e\u96c6\uff0c\u4f7f\u7528\u5206\u7247\uff08Sharding\uff09\u6216\u5206\u533a\uff08Partitioning\uff09\u5c06\u6570\u636e\u5206\u5e03\u5230\u591a\u4e2a\u8282\u70b9\u6216\u5206\u533a\u3002<\/li>\n\n\n\n
                          • \u5206\u7247\u9002\u7528\u4e8e MongoDB \u7b49 NoSQL \u6570\u636e\u5e93\u3002<\/li>\n\n\n\n
                          • \u5206\u533a\u9002\u7528\u4e8e SQL \u6570\u636e\u5e93\u3002<\/li>\n<\/ul>\n\n\n\n
                            \u793a\u4f8b\uff1aMySQL \u5206\u533a<\/strong><\/p>\n\n\n\n
                            CREATE TABLE users (\n  id INT,\n  name VARCHAR(255),\n  created_at DATE\n)\nPARTITION BY RANGE (YEAR(created_at)) (\n  PARTITION p1 VALUES LESS THAN (2000),\n  PARTITION p2 VALUES LESS THAN (2010),\n  PARTITION p3 VALUES LESS THAN MAXVALUE\n);<\/code><\/pre>\n\n\n\n
                            \n\n\n\n
                            \u603b\u7ed3<\/strong>
                            \u6027\u80fd\u4f18\u5316\u6d89\u53ca\u6570\u636e\u5e93\u5c42\u548c\u5e94\u7528\u5c42\u7684\u591a\u91cd\u7b56\u7565\uff0c\u5305\u62ec\u7d22\u5f15\u4f18\u5316\u3001\u7f13\u5b58\u3001\u5f02\u6b65\u64cd\u4f5c\u3001\u8fde\u63a5\u6c60\u3001\u5206\u7247\u5206\u533a\u7b49\u3002\u6839\u636e\u5177\u4f53\u5e94\u7528\u573a\u666f\u9009\u62e9\u9002\u5408\u7684\u4f18\u5316\u65b9\u6848\u53ef\u4ee5\u663e\u8457\u63d0\u5347\u6570\u636e\u5e93\u6027\u80fd\u548c\u7528\u6237\u4f53\u9a8c\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
                            \u5728 JavaScript \u5e94\u7528\u4e2d\u4e0e\u6570\u636e\u5e93\u4ea4\u4e92\u65f6\uff0c\u6027\u80fd\u4f18\u5316\u4e3b\u8981\u4f53\u73b0\u5728\u51cf\u5c11\u67e5\u8be2\u65f6\u95f4\u3001\u964d\u4f4e\u7f51\u7edc\u5ef6\u8fdf\u548c\u63d0\u9ad8\u6570\u636e\u64cd\u4f5c\u7684\u6548 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[72],"tags":[],"class_list":["post-532","post","type-post","status-publish","format-standard","hentry","category-nosql"],"_links":{"self":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/532","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/comments?post=532"}],"version-history":[{"count":1,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/532\/revisions"}],"predecessor-version":[{"id":533,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/532\/revisions\/533"}],"wp:attachment":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/media?parent=532"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/categories?post=532"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/tags?post=532"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}