{"id":157930,"date":"2024-11-03T00:07:20","date_gmt":"2024-11-02T16:07:20","guid":{"rendered":"https:\/\/server.hk\/cnblog\/157930\/"},"modified":"2024-11-03T00:07:21","modified_gmt":"2024-11-02T16:07:21","slug":"%e9%ab%98%e6%95%88%e8%a6%86%e8%93%8b%e6%95%b8%e6%93%9a%e5%ba%ab%e6%93%8d%e4%bd%9c%ef%bc%8c%e8%ae%93%e6%95%b8%e6%93%9a%e7%ae%a1%e7%90%86%e8%ae%8a%e5%be%97%e6%9b%b4%e7%b0%a1%e5%96%ae%ef%bc%88%e8%a6%86","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/157930\/","title":{"rendered":"\u9ad8\u6548\u8986\u84cb\u6578\u64da\u5eab\u64cd\u4f5c\uff0c\u8b93\u6578\u64da\u7ba1\u7406\u8b8a\u5f97\u66f4\u7c21\u55ae\uff08\u8986\u84cb\u6578\u64da\u5eab\uff09"},"content":{"rendered":"<h1 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id=\"%e4%bb%80%e9%ba%bc%e6%98%af%e8%a6%86%e8%93%8b%e6%95%b8%e6%93%9a%e5%ba%ab%ef%bc%9f-tKKXsYVsxj\">\u4ec0\u9ebc\u662f\u8986\u84cb\u6578\u64da\u5eab\uff1f<\/h2>\n<p>\u8986\u84cb\u6578\u64da\u5eab\uff08Covering Index\uff09\u662f\u4e00\u7a2e\u7279\u6b8a\u7684\u7d22\u5f15\u985e\u578b\uff0c\u5b83\u5305\u542b\u4e86\u67e5\u8a62\u6240\u9700\u7684\u6240\u6709\u5217\uff0c\u9019\u6a23\u5728\u57f7\u884c\u67e5\u8a62\u6642\uff0c\u6578\u64da\u5eab\u7cfb\u7d71\u53ef\u4ee5\u76f4\u63a5\u5f9e\u7d22\u5f15\u4e2d\u7372\u53d6\u6240\u9700\u7684\u6578\u64da\uff0c\u800c\u7121\u9700\u8a2a\u554f\u539f\u59cb\u6578\u64da\u8868\u3002\u9019\u7a2e\u65b9\u6cd5\u4e0d\u50c5\u63d0\u9ad8\u4e86\u67e5\u8a62\u6548\u7387\uff0c\u9084\u6e1b\u5c11\u4e86I\/O\u64cd\u4f5c\uff0c\u5f9e\u800c\u52a0\u5feb\u4e86\u6578\u64da\u6aa2\u7d22\u7684\u901f\u5ea6\u3002<\/p>\n<h2 id=\"%e8%a6%86%e8%93%8b%e6%95%b8%e6%93%9a%e5%ba%ab%e7%9a%84%e5%84%aa%e5%8b%a2-tKKXsYVsxj\">\u8986\u84cb\u6578\u64da\u5eab\u7684\u512a\u52e2<\/h2>\n<ul>\n<li><strong>\u63d0\u9ad8\u67e5\u8a62\u6027\u80fd\uff1a<\/strong>\u7531\u65bc\u8986\u84cb\u7d22\u5f15\u5305\u542b\u4e86\u67e5\u8a62\u6240\u9700\u7684\u6240\u6709\u6578\u64da\uff0c\u6578\u64da\u5eab\u53ef\u4ee5\u76f4\u63a5\u5f9e\u7d22\u5f15\u4e2d\u8fd4\u56de\u7d50\u679c\uff0c\u9019\u6a23\u53ef\u4ee5\u986f\u8457\u6e1b\u5c11\u67e5\u8a62\u7684\u57f7\u884c\u6642\u9593\u3002<\/li>\n<li><strong>\u6e1b\u5c11I\/O\u64cd\u4f5c\uff1a<\/strong>\u4f7f\u7528\u8986\u84cb\u7d22\u5f15\u53ef\u4ee5\u6e1b\u5c11\u5c0d\u539f\u59cb\u6578\u64da\u8868\u7684\u8a2a\u554f\uff0c\u5f9e\u800c\u964d\u4f4eI\/O\u64cd\u4f5c\u7684\u6b21\u6578\uff0c\u9019\u5c0d\u65bc\u5927\u578b\u6578\u64da\u5eab\u5c24\u70ba\u91cd\u8981\u3002<\/li>\n<li><strong>\u7c21\u5316\u6578\u64da\u7ba1\u7406\uff1a<\/strong>\u8986\u84cb\u7d22\u5f15\u7684\u4f7f\u7528\u4f7f\u5f97\u6578\u64da\u7ba1\u7406\u8b8a\u5f97\u66f4\u52a0\u7c21\u55ae\uff0c\u56e0\u70ba\u5b83\u53ef\u4ee5\u6e1b\u5c11\u67e5\u8a62\u7684\u8907\u96dc\u6027\uff0c\u4e26\u63d0\u9ad8\u6578\u64da\u6aa2\u7d22\u7684\u6548\u7387\u3002<\/li>\n<\/ul>\n<h2 id=\"%e5%a6%82%e4%bd%95%e5%89%b5%e5%bb%ba%e8%a6%86%e8%93%8b%e6%95%b8%e6%93%9a%e5%ba%ab%e7%b4%a2%e5%bc%95-tKKXsYVsxj\">\u5982\u4f55\u5275\u5efa\u8986\u84cb\u6578\u64da\u5eab\u7d22\u5f15<\/h2>\n<p>\u5728\u5927\u591a\u6578\u95dc\u4fc2\u578b\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\u4e2d\uff0c\u5275\u5efa\u8986\u84cb\u7d22\u5f15\u7684\u8a9e\u6cd5\u76f8\u5c0d\u7c21\u55ae\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u4f7f\u7528 SQL \u8a9e\u8a00\u5275\u5efa\u8986\u84cb\u7d22\u5f15\u7684\u793a\u4f8b\uff1a<\/p>\n<pre><code>CREATE INDEX idx_covering ON employees (last_name, first_name) INCLUDE (email, phone_number);<\/code><\/pre>\n<p>\u5728\u9019\u500b\u4f8b\u5b50\u4e2d\uff0c\u6211\u5011\u70ba\u201cemployees\u201d\u8868\u5275\u5efa\u4e86\u4e00\u500b\u540d\u70ba\u201cidx_covering\u201d\u7684\u7d22\u5f15\uff0c\u8a72\u7d22\u5f15\u5305\u542b\u4e86\u201clast_name\u201d\u548c\u201cfirst_name\u201d\u4f5c\u70ba\u7d22\u5f15\u9375\uff0c\u4e26\u4e14\u9084\u5305\u62ec\u4e86\u201cemail\u201d\u548c\u201cphone_number\u201d\u4f5c\u70ba\u9644\u52a0\u5217\u3002\u9019\u6a23\u7684\u8a2d\u8a08\u53ef\u4ee5\u78ba\u4fdd\u5728\u67e5\u8a62\u6642\uff0c\u6240\u6709\u9700\u8981\u7684\u6578\u64da\u90fd\u53ef\u4ee5\u5f9e\u7d22\u5f15\u4e2d\u7372\u53d6\u3002<\/p>\n<h2 id=\"%e8%a6%86%e8%93%8b%e6%95%b8%e6%93%9a%e5%ba%ab%e7%9a%84%e6%9c%80%e4%bd%b3%e5%af%a6%e8%b8%90-tKKXsYVsxj\">\u8986\u84cb\u6578\u64da\u5eab\u7684\u6700\u4f73\u5be6\u8e10<\/h2>\n<ul>\n<li><strong>\u9078\u64c7\u5408\u9069\u7684\u5217\uff1a<\/strong>\u5728\u5275\u5efa\u8986\u84cb\u7d22\u5f15\u6642\uff0c\u61c9\u8a72\u4ed4\u7d30\u9078\u64c7\u9700\u8981\u5305\u542b\u7684\u5217\uff0c\u78ba\u4fdd\u9019\u4e9b\u5217\u662f\u67e5\u8a62\u4e2d\u7d93\u5e38\u4f7f\u7528\u7684\u3002<\/li>\n<li><strong>\u5b9a\u671f\u7dad\u8b77\u7d22\u5f15\uff1a<\/strong>\u96a8\u8457\u6578\u64da\u7684\u589e\u9577\u548c\u8b8a\u5316\uff0c\u5b9a\u671f\u7dad\u8b77\u7d22\u5f15\u662f\u5fc5\u8981\u7684\uff0c\u4ee5\u78ba\u4fdd\u5176\u6027\u80fd\u4e0d\u6703\u4e0b\u964d\u3002<\/li>\n<li><strong>\u76e3\u63a7\u67e5\u8a62\u6027\u80fd\uff1a<\/strong>\u4f7f\u7528\u6578\u64da\u5eab\u7684\u6027\u80fd\u76e3\u63a7\u5de5\u5177\uff0c\u5b9a\u671f\u6aa2\u67e5\u67e5\u8a62\u7684\u57f7\u884c\u8a08\u5283\uff0c\u78ba\u4fdd\u8986\u84cb\u7d22\u5f15\u7684\u4f7f\u7528\u662f\u6709\u6548\u7684\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b5%90%e8%ab%96-tKKXsYVsxj\">\u7d50\u8ad6<\/h2>\n<p>\u8986\u84cb\u6578\u64da\u5eab\u662f\u4e00\u7a2e\u6709\u6548\u7684\u6280\u8853\uff0c\u53ef\u4ee5\u986f\u8457\u63d0\u9ad8\u6578\u64da\u67e5\u8a62\u7684\u6027\u80fd\uff0c\u4e26\u7c21\u5316\u6578\u64da\u7ba1\u7406\u904e\u7a0b\u3002\u901a\u904e\u5408\u7406\u5730\u8a2d\u8a08\u548c\u4f7f\u7528\u8986\u84cb\u7d22\u5f15\uff0c\u4f01\u696d\u53ef\u4ee5\u5728\u9762\u5c0d\u5927\u91cf\u6578\u64da\u6642\uff0c\u4f9d\u7136\u4fdd\u6301\u9ad8\u6548\u7684\u6578\u64da\u6aa2\u7d22\u80fd\u529b\u3002\u96a8\u8457\u6578\u64da\u91cf\u7684\u6301\u7e8c\u589e\u9577\uff0c\u638c\u63e1\u8986\u84cb\u6578\u64da\u5eab\u7684\u64cd\u4f5c\u5c07\u6210\u70ba\u6578\u64da\u7ba1\u7406\u8005\u5fc5\u5099\u7684\u6280\u80fd\u3002<\/p>\n<p>\u5982\u679c\u60a8\u6b63\u5728\u5c0b\u627e\u9ad8\u6548\u7684\u6578\u64da\u7ba1\u7406\u89e3\u6c7a\u65b9\u6848\uff0c\u8003\u616e\u4f7f\u7528<a 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