{"id":31549,"date":"2023-05-24T11:55:20","date_gmt":"2023-05-24T03:55:20","guid":{"rendered":"https:\/\/docs.pingcode.com\/?p=31549"},"modified":"2023-07-31T00:08:50","modified_gmt":"2023-07-30T16:08:50","slug":"sql%e6%95%b0%e6%8d%ae%e5%ba%93%e4%b8%ad%e4%bb%80%e4%b9%88%e6%83%85%e5%86%b5%e8%af%a5%e5%8a%a0%e7%b4%a2%e5%bc%95index","status":"publish","type":"post","link":"https:\/\/docs.pingcode.com\/ask\/31549.html","title":{"rendered":"sql\u6570\u636e\u5e93\u4e2d\u4ec0\u4e48\u60c5\u51b5\u8be5\u52a0\u7d22\u5f15index"},"content":{"rendered":"<blockquote class=\"wp-block-quote\">\n<p>\u8868\u7684\u67d0\u4e2a\u5b57\u6bb5\u503c\u5f97\u79bb\u6563\u5ea6\u8d8a\u9ad8\uff0c\u8be5\u5b57\u6bb5\u8d8a\u9002\u5408\u9009\u4f5c\u7d22\u5f15\u7684\u5173\u952e\u5b57\u3002\u4e3b\u952e\u5b57\u6bb5\u4ee5\u53ca\u5c11\u6570\u6027\u7ea6\u675f\u5b57\u6bb5\u9002\u5408\u9009\u4f5c\u7d22\u5f15\u7684\u5173\u952e\u5b57\uff0c\u539f\u56e0\u5c31\u662f\u8fd9\u4e9b\u5b57\u6bb5\u7684\u503c\u975e\u5e38\u79bb\u6563\u3002\u5c24\u5176\u662f\u5728\u4e3b\u952e\u5b57\u6bb5\u521b\u5efa\u7d22\u5f15\u65f6\uff0ccardinality\u7684\u503c\u5c31\u7b49\u4e8e\u8be5\u8868\u7684\u884c\u6570\u3002<\/p>\n<\/blockquote>\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full\"><img fetchpriority=\"high\" alt=\"\" class=\"wp-image-31550\" decoding=\"async\" height=\"421\" sizes=\"(max-width: 680px) 100vw, 680px\" src=\"https:\/\/cdn-docs.pingcode.com\/wp-content\/uploads\/2023\/05\/\u6dfb\u52a0\u6807\u9898-19-10.png?x-oss-process=image\/auto-orient,1\/format,webp\" srcset=\"https:\/\/cdn-docs.pingcode.com\/wp-content\/uploads\/2023\/05\/\u6dfb\u52a0\u6807\u9898-19-10.png?x-oss-process=image\/auto-orient,1\/format,webp 680w, https:\/\/cdn-docs.pingcode.com\/wp-content\/uploads\/2023\/05\/\u6dfb\u52a0\u6807\u9898-19-10-300x186.png 300w\" width=\"680\"\/><\/figure>\n<\/div>\n<h2 class=\"wp-block-heading\"><strong>\u4e00\u3001sql\u6570\u636e\u5e93\u4e2d\u4ec0\u4e48\u60c5\u51b5\u8be5\u52a0\u7d22\u5f15index<\/strong><\/h2>\n<p>1\u3001\u8868\u7684\u67d0\u4e2a\u5b57\u6bb5\u503c\u5f97\u79bb\u6563\u5ea6\u8d8a\u9ad8\uff0c\u8be5\u5b57\u6bb5\u8d8a\u9002\u5408\u9009\u4f5c\u7d22\u5f15\u7684\u5173\u952e\u5b57\u3002\u4e3b\u952e\u5b57\u6bb5\u4ee5\u53ca\u5c11\u6570\u6027\u7ea6\u675f\u5b57\u6bb5\u9002\u5408\u9009\u4f5c\u7d22\u5f15\u7684\u5173\u952e\u5b57\uff0c\u539f\u56e0\u5c31\u662f\u8fd9\u4e9b\u5b57\u6bb5\u7684\u503c\u975e\u5e38\u79bb\u6563\u3002\u5c24\u5176\u662f\u5728\u4e3b\u952e\u5b57\u6bb5\u521b\u5efa\u7d22\u5f15\u65f6\uff0ccardinality\u7684\u503c\u5c31\u7b49\u4e8e\u8be5\u8868\u7684\u884c\u6570\u3002<\/p>\n<p>MySQL \u5728\u5904\u7406\u4e3b\u952e\u7ea6\u675f\u4ee5\u53ca\u5c11\u6570\u6027\u7ea6\u675f\u65f6\uff0c\u8003\u8651\u5468\u5168\u3002\u6570\u636e\u5e93\u7528\u6237\u521b\u5efa\u4e3b\u952e\u7ea6\u675f\u7684\u540c\u65f6\uff0c MySQL \u81ea\u52a8\u521b\u5efa\u4e3b\u7d22\u5f15\uff08 primary index \uff09\uff0c\u4e14\u7d22\u5f15\u540d\u79f0\u4e3a Primary\uff1b\u6570\u636e\u5e93\u7528\u6237\u521b\u5efa\u5c11\u6570\u6027\u7d22\u5f15\u65f6\uff0c MySQL \u81ea\u52a8\u521b\u5efa\u5c11\u6570\u6027\u7d22\u5f15\uff08 unique index \uff09\uff0c\u9ed8\u8ba4\u60c5\u51b5\u4e0b\uff0c\u7d22\u5f15\u540d\u4e3a\u5c11\u6570\u6027\u7d22\u5f15\u7684\u5b57\u6bb5\u540d\u3002<\/p>\n<p>2\u3001 \u5360\u7528\u5b58\u50a8\u7a7a\u95f4\u5c11\u7684\u5b57\u6bb5\u66f4\u9002\u5408\u9009\u4f5c\u7d22\u5f15\u7684\u5173\u952e\u5b57\u3002\u4f8b\u5982\uff0c\u4e0e\u5b57\u7b26\u4e32\u76f8\u6bd4\uff0c\u6574\u6570\u5b57\u6bb5\u5360\u7528\u7684\u5b58\u50a8\u7a7a\u95f4\u8f83\u5c11\uff0c\u56e0\u6b64\uff0c\u8f83\u4e3a\u9002\u5408\u9009\u4f5c\u7d22\u5f15\u5173\u952e\u5b57\u3002<\/p>\n<p>3\u3001 \u5b58\u50a8\u7a7a\u95f4\u56fa\u5b9a\u7684\u5b57\u6bb5\u66f4\u9002\u5408\u9009\u4f5c\u7d22\u5f15\u7684\u5173\u952e\u5b57\u3002\u4e0e text \u7c7b\u578b\u7684\u5b57\u6bb5\u76f8\u6bd4\uff0c char \u7c7b\u578b\u7684\u5b57\u6bb5\u8f83\u4e3a\u9002\u5408\u9009\u4f5c\u7d22\u5f15\u5173\u952e\u5b57\u3002<\/p>\n<p>4\u3001 Where \u5b50\u53e5\u4e2d\u7ecf\u5e38\u4f7f\u7528\u7684\u5b57\u6bb5\u5e94\u8be5\u521b\u5efa\u7d22\u5f15\uff0c\u5206\u7ec4\u5b57\u6bb5\u6216\u8005\u6392\u5e8f\u5b57\u6bb5\u5e94\u8be5\u521b\u5efa\u7d22\u5f15\uff0c\u4e24\u4e2a\u8868\u7684\u8fde\u63a5\u5b57\u6bb5\u5e94\u8be5\u521b\u5efa\u7d22\u5f15\u3002<\/p>\n<p>5\u3001 \u66f4\u65b0\u9891\u7e41\u7684\u5b57\u6bb5\u4e0d\u9002\u5408\u521b\u5efa\u7d22\u5f15\uff0c\u4e0d\u4f1a\u51fa\u73b0\u5728 where \u5b50\u53e5\u4e2d\u7684\u5b57\u6bb5\u4e0d\u5e94\u8be5\u521b\u5efa\u7d22\u5f15\u3002<\/p>\n<p>6\u3001 \u6700\u5de6\u524d\u7f00\u539f\u5219\u3002<\/p>\n<p>7\u3001 \u5c3d\u91cf\u4f7f\u7528\u524d\u7f00\u7d22\u5f15\u3002<\/p>\n<p><strong>\u5ef6\u4f38\u9605\u8bfb\uff1a<\/strong><\/p>\n<h2 class=\"wp-block-heading\"><strong>\u4e8c\u3001\u5e94\u7528\u67b6\u6784\u662f\u4ec0\u4e48<\/strong><\/h2>\n<p>\u5e94\u7528\u67b6\u6784\uff08Application Architecture\uff09\u662f\u63cf\u8ff0\u4e86IT\u7cfb\u7edf\u529f\u80fd\u548c\u6280\u672f\u5b9e\u73b0\u7684\u5185\u5bb9\u3002\u5e94\u7528\u67b6\u6784\u5206\u4e3a\u4ee5\u4e0b\u4e24\u4e2a\u4e0d\u540c\u7684\u5c42\u6b21\uff1a<\/p>\n<ul>\n<li>\u4f01\u4e1a\u7ea7\u7684\u5e94\u7528\u67b6\u6784\uff1a\u4f01\u4e1a\u5c42\u9762\u7684\u5e94\u7528\u67b6\u6784\u8d77\u5230\u4e86\u7edf\u4e00\u89c4\u5212\u3001\u627f\u4e0a\u542f\u4e0b\u7684\u4f5c\u7528\uff0c\u5411\u4e0a\u627f\u63a5\u4e86\u4f01\u4e1a\u6218\u7565\u53d1\u5c55\u65b9\u5411\u548c\u4e1a\u52a1\u6a21\u5f0f\uff0c\u5411\u4e0b\u89c4\u5212\u548c\u6307\u5bfc\u4f01\u4e1a\u5404\u4e2aIT\u7cfb\u7edf\u7684\u5b9a\u4f4d\u548c\u529f\u80fd\u3002\u5728\u4f01\u4e1a\u67b6\u6784\u4e2d\uff0c\u5e94\u7528\u67b6\u6784\u662f\u6700\u91cd\u8981\u548c\u5de5\u4f5c\u91cf\u6700\u5927\u7684\u90e8\u5206\uff0c\u4ed6\u5305\u62ec\u4e86\u4f01\u4e1a\u7684\u5e94\u7528\u67b6\u6784\u84dd\u56fe\u3001\u67b6\u6784\u6807\u51c6\/\u539f\u5219\u3001\u7cfb\u7edf\u7684\u8fb9\u754c\u548c\u5b9a\u4e49\u3001\u7cfb\u7edf\u95f4\u7684\u5173\u8054\u5173\u7cfb\u7b49\u65b9\u9762\u7684\u5185\u5bb9\u3002<\/li>\n<\/ul>\n<p>\u5355\u4e2a\u7cfb\u7edf\u7684\u5e94\u7528\u67b6\u6784\uff1a\u5728\u5f00\u53d1\u6216\u8bbe\u8ba1\u5355\u4e00IT\u7cfb\u7edf\u65f6\uff0c\u8bbe\u8ba1\u7cfb\u7edf\u7684\u4e3b\u8981\u6a21\u5757\u548c\u529f\u80fd\u70b9\uff0c\u7cfb\u7edf\u6280\u672f\u5b9e\u73b0\u662f\u4ece\u524d\u7aef\u5c55\u793a\u5230\u4e1a\u52a1\u5904\u7406\u903b\u8f91\uff0c\u5230\u540e\u53f0\u6570\u636e\u662f\u5982\u4f55\u67b6\u6784\u7684\u3002\u8fd9\u65b9\u9762\u7684\u5de5\u4f5c\u4e00\u822c\u5c5e\u4e8e\u9879\u76ee\u7ec4\uff0c\u800c\u4e0d\u662f\u4f01\u4e1a\u67b6\u6784\u7684\u8303\u7574\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"\u8868\u7684\u67d0\u4e2a\u5b57\u6bb5\u503c\u5f97\u79bb\u6563\u5ea6\u8d8a\u9ad8\uff0c\u8be5\u5b57\u6bb5\u8d8a\u9002\u5408\u9009\u4f5c\u7d22\u5f15\u7684\u5173\u952e\u5b57\u3002\u4e3b\u952e\u5b57\u6bb5\u4ee5\u53ca\u5c11\u6570\u6027\u7ea6\u675f\u5b57\u6bb5\u9002\u5408\u9009\u4f5c\u7d22\u5f15\u7684\u5173\u952e\u5b57\uff0c\u539f\u56e0 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