{"id":187014,"date":"2024-11-11T10:44:22","date_gmt":"2024-11-11T02:44:22","guid":{"rendered":"https:\/\/server.hk\/cnblog\/187014\/"},"modified":"2024-11-11T10:44:23","modified_gmt":"2024-11-11T02:44:23","slug":"%e6%95%b8%e6%93%9a%e5%ba%ab%e5%86%97%e9%a4%98%e6%8e%a7%e5%88%b6%ef%bc%9a%e6%8f%90%e9%ab%98%e6%95%b8%e6%93%9a%e7%ae%a1%e7%90%86%e6%95%88%e7%8e%87%e7%9a%84%e9%97%9c%e9%8d%b5-%e5%a6%82%e4%bd%95%e6%8e%a7","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/187014\/","title":{"rendered":"\u6578\u64da\u5eab\u5197\u9918\u63a7\u5236\uff1a\u63d0\u9ad8\u6578\u64da\u7ba1\u7406\u6548\u7387\u7684\u95dc\u9375 (\u5982\u4f55\u63a7\u5236\u6578\u64da\u5eab\u5197\u9918)"},"content":{"rendered":"<h1 id=\"%e6%95%b8%e6%93%9a%e5%ba%ab%e5%86%97%e9%a4%98%e6%8e%a7%e5%88%b6%ef%bc%9a%e6%8f%90%e9%ab%98%e6%95%b8%e6%93%9a%e7%ae%a1%e7%90%86%e6%95%88%e7%8e%87%e7%9a%84%e9%97%9c%e9%8d%b5-KJUEsGdjKx\">\u6578\u64da\u5eab\u5197\u9918\u63a7\u5236\uff1a\u63d0\u9ad8\u6578\u64da\u7ba1\u7406\u6548\u7387\u7684\u95dc\u9375<\/h1>\n<p>\u5728\u7576\u4eca\u6578\u64da\u9a45\u52d5\u7684\u4e16\u754c\u4e2d\uff0c\u6578\u64da\u5eab\u7684\u7ba1\u7406\u6548\u7387\u5c0d\u65bc\u4f01\u696d\u7684\u904b\u71df\u81f3\u95dc\u91cd\u8981\u3002\u6578\u64da\u5eab\u5197\u9918\u662f\u6307\u5728\u6578\u64da\u5eab\u4e2d\u91cd\u8907\u5b58\u5132\u76f8\u540c\u6578\u64da\u7684\u60c5\u6cc1\uff0c\u9019\u4e0d\u50c5\u6d6a\u8cbb\u5b58\u5132\u7a7a\u9593\uff0c\u9084\u53ef\u80fd\u5c0e\u81f4\u6578\u64da\u4e0d\u4e00\u81f4\u6027\u548c\u7ba1\u7406\u56f0\u96e3\u3002\u56e0\u6b64\uff0c\u63a7\u5236\u6578\u64da\u5eab\u5197\u9918\u662f\u63d0\u9ad8\u6578\u64da\u7ba1\u7406\u6548\u7387\u7684\u95dc\u9375\u3002<\/p>\n<h2 id=\"%e4%bb%80%e9%ba%bc%e6%98%af%e6%95%b8%e6%93%9a%e5%ba%ab%e5%86%97%e9%a4%98%ef%bc%9f-KJUEsGdjKx\">\u4ec0\u9ebc\u662f\u6578\u64da\u5eab\u5197\u9918\uff1f<\/h2>\n<p>\u6578\u64da\u5eab\u5197\u9918\u662f\u6307\u5728\u6578\u64da\u5eab\u4e2d\u5b58\u5728\u591a\u500b\u76f8\u540c\u6216\u76f8\u4f3c\u7684\u6578\u64da\u9805\u3002\u9019\u7a2e\u60c5\u6cc1\u901a\u5e38\u767c\u751f\u5728\u6578\u64da\u8a2d\u8a08\u4e0d\u7576\u6216\u6578\u64da\u66f4\u65b0\u4e0d\u4e00\u81f4\u7684\u60c5\u6cc1\u4e0b\u3002\u5197\u9918\u6578\u64da\u53ef\u80fd\u5c0e\u81f4\u4ee5\u4e0b\u554f\u984c\uff1a<\/p>\n<ul>\n<li>\u5b58\u5132\u7a7a\u9593\u6d6a\u8cbb\uff1a\u91cd\u8907\u7684\u6578\u64da\u4f54\u7528\u4e86\u4e0d\u5fc5\u8981\u7684\u5b58\u5132\u7a7a\u9593\u3002<\/li>\n<li>\u6578\u64da\u4e0d\u4e00\u81f4\u6027\uff1a\u7576\u6578\u64da\u66f4\u65b0\u6642\uff0c\u82e5\u672a\u80fd\u540c\u6b65\u6240\u6709\u5197\u9918\u6578\u64da\uff0c\u5c07\u5c0e\u81f4\u6578\u64da\u4e0d\u4e00\u81f4\u3002<\/li>\n<li>\u7ba1\u7406\u8907\u96dc\u6027\uff1a\u5197\u9918\u6578\u64da\u4f7f\u5f97\u6578\u64da\u7ba1\u7406\u8b8a\u5f97\u66f4\u52a0\u8907\u96dc\uff0c\u589e\u52a0\u4e86\u7dad\u8b77\u7684\u96e3\u5ea6\u3002<\/li>\n<\/ul>\n<h2 id=\"%e5%a6%82%e4%bd%95%e6%8e%a7%e5%88%b6%e6%95%b8%e6%93%9a%e5%ba%ab%e5%86%97%e9%a4%98-KJUEsGdjKx\">\u5982\u4f55\u63a7\u5236\u6578\u64da\u5eab\u5197\u9918<\/h2>\n<p>\u63a7\u5236\u6578\u64da\u5eab\u5197\u9918\u7684\u7b56\u7565\u4e3b\u8981\u5305\u62ec\u6578\u64da\u5eab\u8a2d\u8a08\u3001\u6b63\u898f\u5316\u548c\u6578\u64da\u6e05\u7406\u7b49\u65b9\u6cd5\u3002<\/p>\n<h3 id=\"1-%e6%95%b8%e6%93%9a%e5%ba%ab%e8%a8%ad%e8%a8%88-KJUEsGdjKx\">1. 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\u6b63\u898f\u5316<\/h3>\n<p>\u6b63\u898f\u5316\u662f\u6307\u901a\u904e\u5c07\u6578\u64da\u5206\u89e3\u70ba\u591a\u500b\u76f8\u95dc\u7684\u8868\u4f86\u6d88\u9664\u5197\u9918\u3002\u6b63\u898f\u5316\u7684\u904e\u7a0b\u901a\u5e38\u5305\u62ec\u4ee5\u4e0b\u5e7e\u500b\u968e\u6bb5\uff1a<\/p>\n<ul>\n<li><strong>\u7b2c\u4e00\u6b63\u898f\u5f62 (1NF)<\/strong>\uff1a\u78ba\u4fdd\u6bcf\u500b\u8868\u683c\u4e2d\u7684\u6bcf\u4e00\u5217\u90fd\u662f\u539f\u5b50\u6027\u7684\uff0c\u5373\u6bcf\u500b\u6b04\u4f4d\u53ea\u80fd\u5305\u542b\u4e00\u500b\u503c\u3002<\/li>\n<li><strong>\u7b2c\u4e8c\u6b63\u898f\u5f62 (2NF)<\/strong>\uff1a\u6d88\u9664\u90e8\u5206\u4f9d\u8cf4\uff0c\u78ba\u4fdd\u6bcf\u500b\u975e\u4e3b\u9375\u6b04\u4f4d\u90fd\u5b8c\u5168\u4f9d\u8cf4\u65bc\u4e3b\u9375\u3002<\/li>\n<li><strong>\u7b2c\u4e09\u6b63\u898f\u5f62 (3NF)<\/strong>\uff1a\u6d88\u9664\u50b3\u905e\u4f9d\u8cf4\uff0c\u78ba\u4fdd\u975e\u4e3b\u9375\u6b04\u4f4d\u4e0d\u4f9d\u8cf4\u65bc\u5176\u4ed6\u975e\u4e3b\u9375\u6b04\u4f4d\u3002<\/li>\n<\/ul>\n<p>\u4f8b\u5982\uff0c\u5047\u8a2d\u6709\u4e00\u500b\u5b78\u751f\u8868\uff0c\u5305\u542b\u5b78\u751fID\u3001\u59d3\u540d\u548c\u8ab2\u7a0b\u540d\u7a31\u3002\u5982\u679c\u4e00\u500b\u5b78\u751f\u53ef\u4ee5\u9078\u64c7\u591a\u500b\u8ab2\u7a0b\uff0c\u5247\u61c9\u5c07\u8ab2\u7a0b\u540d\u7a31\u79fb\u81f3\u53e6\u4e00\u500b\u8868\u4e2d\uff0c\u4e26\u901a\u904e\u5b78\u751fID\u9032\u884c\u95dc\u806f\uff0c\u9019\u6a23\u53ef\u4ee5\u907f\u514d\u91cd\u8907\u5b58\u5132\u5b78\u751f\u4fe1\u606f\u3002<\/p>\n<h3 id=\"3-%e6%95%b8%e6%93%9a%e6%b8%85%e7%90%86-KJUEsGdjKx\">3. \u6578\u64da\u6e05\u7406<\/h3>\n<p>\u5b9a\u671f\u9032\u884c\u6578\u64da\u6e05\u7406\u662f\u63a7\u5236\u5197\u9918\u7684\u53e6\u4e00\u7a2e\u6709\u6548\u65b9\u6cd5\u3002\u6578\u64da\u6e05\u7406\u7684\u904e\u7a0b\u5305\u62ec\uff1a<\/p>\n<ul>\n<li>\u8b58\u5225\u5197\u9918\u6578\u64da\uff1a\u4f7f\u7528\u67e5\u8a62\u8a9e\u8a00\uff08\u5982SQL\uff09\u4f86\u67e5\u627e\u91cd\u8907\u7684\u6578\u64da\u8a18\u9304\u3002<\/li>\n<li>\u5408\u4f75\u6216\u522a\u9664\u5197\u9918\u6578\u64da\uff1a\u6839\u64da\u696d\u52d9\u9700\u6c42\uff0c\u5408\u4f75\u91cd\u8907\u7684\u6578\u64da\u8a18\u9304\u6216\u522a\u9664\u4e0d\u5fc5\u8981\u7684\u5197\u9918\u6578\u64da\u3002<\/li>\n<\/ul>\n<pre><code>-- \u67e5\u627e\u91cd\u8907\u7684\u5b78\u751f\u8a18\u9304\nSELECT student_id, COUNT(*)\nFROM students\nGROUP BY student_id\nHAVING COUNT(*) &gt; 1;<\/code><\/pre>\n<h2 id=\"%e7%b5%90%e8%ab%96-KJUEsGdjKx\">\u7d50\u8ad6<\/h2>\n<p>\u63a7\u5236\u6578\u64da\u5eab\u5197\u9918\u662f\u63d0\u9ad8\u6578\u64da\u7ba1\u7406\u6548\u7387\u7684\u95dc\u9375\u3002\u901a\u904e\u826f\u597d\u7684\u6578\u64da\u5eab\u8a2d\u8a08\u3001\u6b63\u898f\u5316\u548c\u5b9a\u671f\u7684\u6578\u64da\u6e05\u7406\uff0c\u4f01\u696d\u53ef\u4ee5\u6709\u6548\u5730\u6e1b\u5c11\u5197\u9918\u6578\u64da\u7684\u51fa\u73fe\uff0c\u5f9e\u800c\u63d0\u9ad8\u6578\u64da\u7684\u6e96\u78ba\u6027\u548c\u4e00\u81f4\u6027\u3002\u96a8\u8457\u6578\u64da\u91cf\u7684\u589e\u9577\uff0c\u9019\u4e9b\u63aa\u65bd\u5c07\u8b8a\u5f97\u8d8a\u4f86\u8d8a\u91cd\u8981\uff0c\u5e6b\u52a9\u4f01\u696d\u5728\u7af6\u722d\u4e2d\u4fdd\u6301\u512a\u52e2\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 href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a>\u6216<a href=\"https:\/\/server.hk\">\u4e91\u670d\u52a1\u5668<\/a>\u4f86\u652f\u6301\u60a8\u7684\u6578\u64da\u5eab\u9700\u6c42\uff0c\u78ba\u4fdd\u60a8\u7684\u6578\u64da\u7ba1\u7406\u7cfb\u7d71\u904b\u884c\u9806\u66a2\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u63a2\u7d22\u6578\u64da\u5eab\u5197\u9918\u63a7\u5236\u7684\u7b56\u7565\uff0c\u63d0\u5347\u6578\u64da\u7ba1\u7406\u6548\u7387\uff0c\u78ba\u4fdd\u6578\u64da\u4e00\u81f4\u6027\u8207\u6e96\u78ba\u6027\uff0c\u512a\u5316\u8cc7\u6e90\u5229\u7528\u3002<\/p>\n","protected":false},"author":0,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-187014","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/187014","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/types\/post"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=187014"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/187014\/revisions"}],"predecessor-version":[{"id":187015,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/187014\/revisions\/187015"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=187014"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=187014"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=187014"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}