{"id":188452,"date":"2024-11-11T22:50:28","date_gmt":"2024-11-11T14:50:28","guid":{"rendered":"https:\/\/server.hk\/cnblog\/188452\/"},"modified":"2024-11-11T22:50:29","modified_gmt":"2024-11-11T14:50:29","slug":"%e6%8e%a2%e7%a9%b6%e6%95%b8%e6%93%9a%e5%ba%ab%e7%9a%84%e9%97%9c%e4%bf%82%e6%bc%94%e7%ae%97%e6%80%9d%e6%83%b3-%e6%95%b8%e6%93%9a%e5%ba%ab-%e9%97%9c%e4%bf%82%e6%bc%94%e7%ae%97","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/188452\/","title":{"rendered":"\u63a2\u7a76\u6578\u64da\u5eab\u7684\u95dc\u4fc2\u6f14\u7b97\u601d\u60f3 (\u6578\u64da\u5eab \u95dc\u4fc2\u6f14\u7b97)"},"content":{"rendered":"<h1 id=\"%e6%8e%a2%e7%a9%b6%e6%95%b8%e6%93%9a%e5%ba%ab%e7%9a%84%e9%97%9c%e4%bf%82%e6%bc%94%e7%ae%97%e6%80%9d%e6%83%b3-%e6%95%b8%e6%93%9a%e5%ba%ab-%e9%97%9c%e4%bf%82%e6%bc%94%e7%ae%97-MHlRMeahrT\">\u63a2\u7a76\u6578\u64da\u5eab\u7684\u95dc\u4fc2\u6f14\u7b97\u601d\u60f3 (\u6578\u64da\u5eab \u95dc\u4fc2\u6f14\u7b97)<\/h1>\n<p>\u5728\u7576\u4eca\u6578\u64da\u9a45\u52d5\u7684\u6642\u4ee3\uff0c\u6578\u64da\u5eab\u7684\u8a2d\u8a08\u548c\u67e5\u8a62\u65b9\u6cd5\u5c0d\u65bc\u4fe1\u606f\u7684\u5b58\u5132\u548c\u6aa2\u7d22\u81f3\u95dc\u91cd\u8981\u3002\u95dc\u4fc2\u6f14\u7b97\u4f5c\u70ba\u4e00\u7a2e\u6578\u64da\u5eab\u67e5\u8a62\u8a9e\u8a00\u7684\u7406\u8ad6\u57fa\u790e\uff0c\u63d0\u4f9b\u4e86\u4e00\u7a2e\u5f37\u5927\u7684\u65b9\u5f0f\u4f86\u8868\u9054\u6578\u64da\u67e5\u8a62\u7684\u908f\u8f2f\u3002\u672c\u6587\u5c07\u6df1\u5165\u63a2\u8a0e\u95dc\u4fc2\u6f14\u7b97\u7684\u57fa\u672c\u6982\u5ff5\u3001\u7279\u9ede\u53ca\u5176\u5728\u6578\u64da\u5eab\u4e2d\u7684\u61c9\u7528\u3002<\/p>\n<h2 id=\"%e4%bb%80%e9%ba%bc%e6%98%af%e9%97%9c%e4%bf%82%e6%bc%94%e7%ae%97%ef%bc%9f-MHlRMeahrT\">\u4ec0\u9ebc\u662f\u95dc\u4fc2\u6f14\u7b97\uff1f<\/h2>\n<p>\u95dc\u4fc2\u6f14\u7b97\u662f\u4e00\u7a2e\u57fa\u65bc\u6578\u5b78\u908f\u8f2f\u7684\u67e5\u8a62\u8a9e\u8a00\uff0c\u4e3b\u8981\u7528\u65bc\u95dc\u4fc2\u578b\u6578\u64da\u5eab\u4e2d\u3002\u5b83\u7684\u6838\u5fc3\u601d\u60f3\u662f\u901a\u904e\u63cf\u8ff0\u6240\u9700\u6578\u64da\u7684\u5c6c\u6027\u548c\u689d\u4ef6\u4f86\u9032\u884c\u67e5\u8a62\uff0c\u800c\u4e0d\u662f\u5177\u9ad4\u7684\u64cd\u4f5c\u6b65\u9a5f\u3002\u9019\u7a2e\u65b9\u6cd5\u4f7f\u5f97\u7528\u6236\u53ef\u4ee5\u5c08\u6ce8\u65bc\u6578\u64da\u7684\u201c\u4ec0\u9ebc\u201d\u800c\u975e\u201c\u600e\u9ebc\u505a\u201d\u3002<\/p>\n<h2 id=\"%e9%97%9c%e4%bf%82%e6%bc%94%e7%ae%97%e7%9a%84%e9%a1%9e%e5%9e%8b-MHlRMeahrT\">\u95dc\u4fc2\u6f14\u7b97\u7684\u985e\u578b<\/h2>\n<p>\u95dc\u4fc2\u6f14\u7b97\u4e3b\u8981\u5206\u70ba\u5169\u7a2e\u985e\u578b\uff1a\u5143\u7d44\u95dc\u4fc2\u6f14\u7b97\uff08Tuple Relational Calculus, TRC\uff09\u548c\u57df\u95dc\u4fc2\u6f14\u7b97\uff08Domain Relational Calculus, DRC\uff09\u3002<\/p>\n<h3 id=\"%e5%85%83%e7%b5%84%e9%97%9c%e4%bf%82%e6%bc%94%e7%ae%97-trc-MHlRMeahrT\">\u5143\u7d44\u95dc\u4fc2\u6f14\u7b97 (TRC)<\/h3>\n<p>\u5143\u7d44\u95dc\u4fc2\u6f14\u7b97\u4f7f\u7528\u5143\u7d44\u8b8a\u91cf\u4f86\u8868\u793a\u67e5\u8a62\u7d50\u679c\u4e2d\u7684\u884c\u3002\u7528\u6236\u53ef\u4ee5\u901a\u904e\u6307\u5b9a\u5143\u7d44\u7684\u5c6c\u6027\u4f86\u63cf\u8ff0\u6240\u9700\u7684\u6578\u64da\u3002\u4f8b\u5982\uff0c\u5047\u8a2d\u6709\u4e00\u500b\u540d\u70ba\u201c\u5b78\u751f\u201d\u7684\u8868\uff0c\u5305\u542b\u201c\u59d3\u540d\u201d\u548c\u201c\u5e74\u9f61\u201d\u5169\u500b\u5c6c\u6027\uff0c\u4ee5\u4e0b\u662f\u4f7f\u7528TRC\u9032\u884c\u67e5\u8a62\u7684\u793a\u4f8b\uff1a<\/p>\n<pre><code> { T | T \u2208 \u5b78\u751f \u2227 T.\u5e74\u9f61 &gt; 18 } <\/code><\/pre>\n<p>\u9019\u500b\u67e5\u8a62\u7684\u610f\u601d\u662f\uff1a\u9078\u64c7\u6240\u6709\u5e74\u9f61\u5927\u65bc18\u6b72\u7684\u5b78\u751f\u5143\u7d44\u3002<\/p>\n<h3 id=\"%e5%9f%9f%e9%97%9c%e4%bf%82%e6%bc%94%e7%ae%97-drc-MHlRMeahrT\">\u57df\u95dc\u4fc2\u6f14\u7b97 (DRC)<\/h3>\n<p>\u57df\u95dc\u4fc2\u6f14\u7b97\u5247\u4f7f\u7528\u57df\u8b8a\u91cf\u4f86\u8868\u793a\u67e5\u8a62\u7d50\u679c\u4e2d\u7684\u5c6c\u6027\u503c\u3002\u9019\u7a2e\u65b9\u6cd5\u66f4\u70ba\u9748\u6d3b\uff0c\u56e0\u70ba\u5b83\u5141\u8a31\u7528\u6236\u76f4\u63a5\u64cd\u4f5c\u5c6c\u6027\u503c\u3002\u4f8b\u5982\uff0c\u5c0d\u65bc\u540c\u6a23\u7684\u201c\u5b78\u751f\u201d\u8868\uff0cDRC\u7684\u67e5\u8a62\u53ef\u4ee5\u5beb\u6210\uff1a<\/p>\n<pre><code> { x, y | \u2203 T (T \u2208 \u5b78\u751f \u2227 T.\u59d3\u540d = x \u2227 T.\u5e74\u9f61 = y \u2227 y &gt; 18) } <\/code><\/pre>\n<p>\u9019\u88e1\uff0cx\u548cy\u5206\u5225\u4ee3\u8868\u5b78\u751f\u7684\u59d3\u540d\u548c\u5e74\u9f61\uff0c\u67e5\u8a62\u7684\u7d50\u679c\u662f\u6240\u6709\u5e74\u9f61\u5927\u65bc18\u6b72\u7684\u5b78\u751f\u59d3\u540d\u548c\u5e74\u9f61\u3002<\/p>\n<h2 id=\"%e9%97%9c%e4%bf%82%e6%bc%94%e7%ae%97%e7%9a%84%e7%89%b9%e9%bb%9e-MHlRMeahrT\">\u95dc\u4fc2\u6f14\u7b97\u7684\u7279\u9ede<\/h2>\n<ul>\n<li><strong>\u975e\u7a0b\u5e8f\u6027\uff1a<\/strong>\u95dc\u4fc2\u6f14\u7b97\u4e0d\u95dc\u5fc3\u5982\u4f55\u7372\u53d6\u6578\u64da\uff0c\u800c\u662f\u95dc\u5fc3\u7372\u53d6\u4ec0\u9ebc\u6578\u64da\u3002<\/li>\n<li><strong>\u9748\u6d3b\u6027\uff1a<\/strong>\u7528\u6236\u53ef\u4ee5\u6839\u64da\u9700\u8981\u81ea\u7531\u7d44\u5408\u67e5\u8a62\u689d\u4ef6\uff0c\u8868\u9054\u80fd\u529b\u5f37\u3002<\/li>\n<li><strong>\u6578\u5b78\u57fa\u790e\uff1a<\/strong>\u57fa\u65bc\u908f\u8f2f\u548c\u96c6\u5408\u7406\u8ad6\uff0c\u63d0\u4f9b\u4e86\u56b4\u8b39\u7684\u7406\u8ad6\u652f\u6301\u3002<\/li>\n<\/ul>\n<h2 id=\"%e9%97%9c%e4%bf%82%e6%bc%94%e7%ae%97%e7%9a%84%e6%87%89%e7%94%a8-MHlRMeahrT\">\u95dc\u4fc2\u6f14\u7b97\u7684\u61c9\u7528<\/h2>\n<p>\u95dc\u4fc2\u6f14\u7b97\u5728\u6578\u64da\u5eab\u67e5\u8a62\u4e2d\u5177\u6709\u5ee3\u6cdb\u7684\u61c9\u7528\u3002\u8a31\u591a\u73fe\u4ee3\u6578\u64da\u5eab\u7cfb\u7d71\uff0c\u5982PostgreSQL\u548cMySQL\uff0c\u96d6\u7136\u4e3b\u8981\u4f7f\u7528SQL\u8a9e\u8a00\u9032\u884c\u67e5\u8a62\uff0c\u4f46\u5176\u80cc\u5f8c\u7684\u908f\u8f2f\u548c\u7406\u8ad6\u57fa\u790e\u4ecd\u7136\u6e90\u65bc\u95dc\u4fc2\u6f14\u7b97\u3002\u901a\u904e\u7406\u89e3\u95dc\u4fc2\u6f14\u7b97\uff0c\u7528\u6236\u53ef\u4ee5\u66f4\u6df1\u5165\u5730\u638c\u63e1\u6578\u64da\u5eab\u7684\u904b\u4f5c\u539f\u7406\uff0c\u5f9e\u800c\u512a\u5316\u67e5\u8a62\u6027\u80fd\u3002<\/p>\n<h2 id=\"%e7%b5%90%e8%ab%96-MHlRMeahrT\">\u7d50\u8ad6<\/h2>\n<p>\u95dc\u4fc2\u6f14\u7b97\u4f5c\u70ba\u6578\u64da\u5eab\u67e5\u8a62\u7684\u7406\u8ad6\u57fa\u790e\uff0c\u63d0\u4f9b\u4e86\u4e00\u7a2e\u9748\u6d3b\u4e14\u5f37\u5927\u7684\u65b9\u5f0f\u4f86\u8868\u9054\u6578\u64da\u67e5\u8a62\u3002\u7121\u8ad6\u662f\u5143\u7d44\u95dc\u4fc2\u6f14\u7b97\u9084\u662f\u57df\u95dc\u4fc2\u6f14\u7b97\uff0c\u90fd\u80fd\u5e6b\u52a9\u7528\u6236\u66f4\u6709\u6548\u5730\u7372\u53d6\u6240\u9700\u6578\u64da\u3002\u96a8\u8457\u6578\u64da\u5eab\u6280\u8853\u7684\u767c\u5c55\uff0c\u5c0d\u95dc\u4fc2\u6f14\u7b97\u7684\u7406\u89e3\u5c07\u6709\u52a9\u65bc\u958b\u767c\u66f4\u9ad8\u6548\u7684\u6578\u64da\u8655\u7406\u7cfb\u7d71\u3002<\/p>\n<p>\u5982\u679c\u60a8\u5c0d\u65bc\u6578\u64da\u5eab\u7684\u904b\u7528\u6709\u9032\u4e00\u6b65\u7684\u9700\u6c42\uff0c\u7121\u8ad6\u662f\u9078\u64c7\u5408\u9069\u7684 <a href=\"https:\/\/server.hk\">VPS<\/a> \u9084\u662f\u4e86\u89e3\u66f4\u591a\u95dc\u65bc <a href=\"https:\/\/server.hk\">\u9999\u6e2f\u4f3a\u670d\u5668<\/a> \u7684\u8cc7\u8a0a\uff0c\u6b61\u8fce\u8a2a\u554f\u6211\u5011\u7684\u7db2\u7ad9\u4ee5\u7372\u53d6\u66f4\u591a\u8a73\u7d30\u8cc7\u6599\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u63a2\u7d22\u6578\u64da\u5eab\u4e2d\u7684\u95dc\u4fc2\u6f14\u7b97\u601d\u60f3\uff0c\u4e86\u89e3\u5176\u57fa\u672c\u539f\u5247\u53ca\u61c9\u7528\uff0c\u63d0\u5347\u6578\u64da\u67e5\u8a62\u8207\u7ba1\u7406\u7684\u6548\u7387\u8207\u9748\u6d3b\u6027\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-188452","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/188452","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=188452"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/188452\/revisions"}],"predecessor-version":[{"id":188453,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/188452\/revisions\/188453"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=188452"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=188452"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=188452"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}