{"id":63674,"date":"2024-10-14T01:31:17","date_gmt":"2024-10-13T17:31:17","guid":{"rendered":"https:\/\/server.hk\/cnblog\/63674\/"},"modified":"2024-10-14T01:31:17","modified_gmt":"2024-10-13T17:31:17","slug":"mongodb%e8%a1%93%e8%aa%9e-map-reduce","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/63674\/","title":{"rendered":"MongoDB\u8853\u8a9e &#8211; Map-Reduce"},"content":{"rendered":"<h1 id=\"mongodb%e8%a1%93%e8%aa%9e-map-reduce-dwWVMdywDy\">MongoDB\u8853\u8a9e &#8211; Map-Reduce<\/h1>\n<p>\u5728\u5927\u6578\u64da\u8655\u7406\u7684\u9818\u57df\u4e2d\uff0cMongoDB\u4f5c\u70ba\u4e00\u500b\u6d41\u884c\u7684NoSQL\u6578\u64da\u5eab\uff0c\u63d0\u4f9b\u4e86\u591a\u7a2e\u6578\u64da\u8655\u7406\u548c\u5206\u6790\u7684\u5de5\u5177\u3002\u5176\u4e2d\uff0cMap-Reduce\u662f\u4e00\u7a2e\u5f37\u5927\u7684\u6578\u64da\u8655\u7406\u6a21\u578b\uff0c\u80fd\u5920\u6709\u6548\u5730\u8655\u7406\u5927\u91cf\u6578\u64da\u3002\u672c\u6587\u5c07\u6df1\u5165\u63a2\u8a0eMongoDB\u4e2d\u7684Map-Reduce\u6982\u5ff5\u3001\u5176\u5de5\u4f5c\u539f\u7406\u4ee5\u53ca\u5be6\u969b\u61c9\u7528\u793a\u4f8b\u3002<\/p>\n<h2 id=\"%e4%bb%80%e9%ba%bc%e6%98%afmap-reduce%ef%bc%9f-dwWVMdywDy\">\u4ec0\u9ebc\u662fMap-Reduce\uff1f<\/h2>\n<p>Map-Reduce\u662f\u4e00\u7a2e\u7de8\u7a0b\u6a21\u578b\uff0c\u6700\u65e9\u7531Google\u63d0\u51fa\uff0c\u7528\u65bc\u8655\u7406\u548c\u751f\u6210\u5927\u6578\u64da\u96c6\u3002\u9019\u4e00\u6a21\u578b\u4e3b\u8981\u7531\u5169\u500b\u6b65\u9a5f\u7d44\u6210\uff1aMap\u548cReduce\u3002<\/p>\n<ul>\n<li><strong>Map\uff1a<\/strong>\u9019\u4e00\u6b65\u9a5f\u5c07\u8f38\u5165\u6578\u64da\u8f49\u63db\u70ba\u4e00\u7d44\u9375\u503c\u5c0d\u3002\u6bcf\u500b\u8f38\u5165\u6578\u64da\u9805\u90fd\u6703\u88ab\u6620\u5c04\u5230\u4e00\u500b\u6216\u591a\u500b\u9375\u503c\u5c0d\u3002<\/li>\n<li><strong>Reduce\uff1a<\/strong>\u9019\u4e00\u6b65\u9a5f\u5c07\u4f86\u81eaMap\u6b65\u9a5f\u7684\u9375\u503c\u5c0d\u9032\u884c\u5408\u4f75\uff0c\u751f\u6210\u6700\u7d42\u7684\u8f38\u51fa\u7d50\u679c\u3002<\/li>\n<\/ul>\n<h2 id=\"mongodb%e4%b8%ad%e7%9a%84map-reduce-dwWVMdywDy\">MongoDB\u4e2d\u7684Map-Reduce<\/h2>\n<p>\u5728MongoDB\u4e2d\uff0cMap-Reduce\u662f\u4e00\u7a2e\u7528\u65bc\u57f7\u884c\u805a\u5408\u64cd\u4f5c\u7684\u5de5\u5177\u3002\u96d6\u7136MongoDB\u9084\u63d0\u4f9b\u4e86\u5176\u4ed6\u805a\u5408\u6846\u67b6\uff0c\u4f46Map-Reduce\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\u4ecd\u7136\u975e\u5e38\u6709\u7528\uff0c\u7279\u5225\u662f\u7576\u9700\u8981\u9032\u884c\u8907\u96dc\u7684\u8a08\u7b97\u6642\u3002<\/p>\n<h3 id=\"map-reduce%e7%9a%84%e5%b7%a5%e4%bd%9c%e6%b5%81%e7%a8%8b-dwWVMdywDy\">Map-Reduce\u7684\u5de5\u4f5c\u6d41\u7a0b<\/h3>\n<p>\u5728MongoDB\u4e2d\u4f7f\u7528Map-Reduce\u7684\u57fa\u672c\u6d41\u7a0b\u5982\u4e0b\uff1a<\/p>\n<ol>\n<li>\u5b9a\u7fa9Map\u51fd\u6578\uff1a\u9019\u500b\u51fd\u6578\u8ca0\u8cac\u5c07\u8f38\u5165\u6578\u64da\u8f49\u63db\u70ba\u9375\u503c\u5c0d\u3002<\/li>\n<li>\u5b9a\u7fa9Reduce\u51fd\u6578\uff1a\u9019\u500b\u51fd\u6578\u8ca0\u8cac\u5408\u4f75\u4f86\u81eaMap\u6b65\u9a5f\u7684\u9375\u503c\u5c0d\u3002<\/li>\n<li>\u57f7\u884cMap-Reduce\u64cd\u4f5c\uff1a\u4f7f\u7528MongoDB\u7684\u547d\u4ee4\u4f86\u57f7\u884cMap-Reduce\u3002<\/li>\n<\/ol>\n<h3 id=\"%e7%af%84%e4%be%8b%e4%bb%a3%e7%a2%bc-dwWVMdywDy\">\u7bc4\u4f8b\u4ee3\u78bc<\/h3>\n<p>\u4ee5\u4e0b\u662f\u4e00\u500b\u7c21\u55ae\u7684Map-Reduce\u7bc4\u4f8b\uff0c\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u540d\u70ba\u201corders\u201d\u7684\u96c6\u5408\uff0c\u8a18\u9304\u4e86\u6bcf\u500b\u8a02\u55ae\u7684\u91d1\u984d\uff1a<\/p>\n<pre><code>\ndb.orders.mapReduce(\n    function() {\n        emit(this.product, this.amount);\n    },\n    function(key, values) {\n        return Array.sum(values);\n    },\n    {\n        out: \"total_sales\"\n    }\n);\n<\/code><\/pre>\n<p>\u5728\u9019\u500b\u7bc4\u4f8b\u4e2d\uff0cMap\u51fd\u6578\u5c07\u6bcf\u500b\u8a02\u55ae\u7684\u7522\u54c1\u548c\u91d1\u984d\u4f5c\u70ba\u9375\u503c\u5c0d\u8f38\u51fa\uff0c\u800cReduce\u51fd\u6578\u5247\u8a08\u7b97\u6bcf\u500b\u7522\u54c1\u7684\u7e3d\u92b7\u552e\u984d\u3002\u6700\u7d42\u7d50\u679c\u5c07\u5b58\u5132\u5728\u540d\u70ba\u201ctotal_sales\u201d\u7684\u96c6\u5408\u4e2d\u3002<\/p>\n<h2 id=\"map-reduce%e7%9a%84%e5%84%aa%e7%bc%ba%e9%bb%9e-dwWVMdywDy\">Map-Reduce\u7684\u512a\u7f3a\u9ede<\/h2>\n<h3 id=\"%e5%84%aa%e9%bb%9e-dwWVMdywDy\">\u512a\u9ede<\/h3>\n<ul>\n<li>\u9748\u6d3b\u6027\uff1aMap-Reduce\u53ef\u4ee5\u8655\u7406\u8907\u96dc\u7684\u8a08\u7b97\u548c\u805a\u5408\u64cd\u4f5c\u3002<\/li>\n<li>\u53ef\u64f4\u5c55\u6027\uff1a\u9069\u5408\u8655\u7406\u5927\u898f\u6a21\u6578\u64da\u96c6\uff0c\u80fd\u5920\u5728\u591a\u500b\u4f3a\u670d\u5668\u4e0a\u4e26\u884c\u8655\u7406\u3002<\/li>\n<\/ul>\n<h3 id=\"%e7%bc%ba%e9%bb%9e-dwWVMdywDy\">\u7f3a\u9ede<\/h3>\n<ul>\n<li>\u6027\u80fd\uff1a\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\uff0cMap-Reduce\u7684\u6027\u80fd\u53ef\u80fd\u4e0d\u5982MongoDB\u7684\u805a\u5408\u6846\u67b6\u3002<\/li>\n<li>\u8907\u96dc\u6027\uff1a\u9700\u8981\u7de8\u5beb\u81ea\u5b9a\u7fa9\u7684Map\u548cReduce\u51fd\u6578\uff0c\u589e\u52a0\u4e86\u958b\u767c\u7684\u8907\u96dc\u6027\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b5%90%e8%ab%96-dwWVMdywDy\">\u7d50\u8ad6<\/h2>\n<p>Map-Reduce\u662f\u4e00\u7a2e\u5f37\u5927\u7684\u6578\u64da\u8655\u7406\u5de5\u5177\uff0c\u7279\u5225\u9069\u5408\u65bc\u9700\u8981\u9032\u884c\u8907\u96dc\u8a08\u7b97\u7684\u5834\u666f\u3002\u96d6\u7136MongoDB\u63d0\u4f9b\u4e86\u5176\u4ed6\u66f4\u9ad8\u6548\u7684\u805a\u5408\u65b9\u6cd5\uff0c\u4f46\u5728\u67d0\u4e9b\u7279\u5b9a\u60c5\u6cc1\u4e0b\uff0cMap-Reduce\u4ecd\u7136\u662f\u4e00\u500b\u4e0d\u53ef\u6216\u7f3a\u7684\u9078\u64c7\u3002\u5c0d\u65bc\u9700\u8981\u8655\u7406\u5927\u91cf\u6578\u64da\u7684\u958b\u767c\u8005\u4f86\u8aaa\uff0c\u7406\u89e3Map-Reduce\u7684\u5de5\u4f5c\u539f\u7406\u53ca\u5176\u61c9\u7528\u5c07\u6709\u52a9\u65bc\u66f4\u597d\u5730\u5229\u7528MongoDB\u7684\u529f\u80fd\u3002<\/p>\n<p>\u5982\u679c\u60a8\u5c0d\u65bcVPS\u3001<a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a>\u6216\u5176\u4ed6\u4f3a\u670d\u5668\u89e3\u6c7a\u65b9\u6848\u6709\u8208\u8da3\uff0c\u6b61\u8fce\u8a2a\u554f\u6211\u5011\u7684\u7db2\u7ad9\u4ee5\u7372\u53d6\u66f4\u591a\u8cc7\u8a0a\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Learn about MongoDB&#8217;s Map-Reduce, a powerful data processing technique for aggregating and transforming large datasets efficiently.<\/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-63674","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/63674","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=63674"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/63674\/revisions"}],"predecessor-version":[{"id":63675,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/63674\/revisions\/63675"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=63674"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=63674"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=63674"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}