{"id":63814,"date":"2024-10-14T02:42:14","date_gmt":"2024-10-13T18:42:14","guid":{"rendered":"https:\/\/server.hk\/cnblog\/63814\/"},"modified":"2024-10-14T02:42:14","modified_gmt":"2024-10-13T18:42:14","slug":"mongodb%e8%a1%93%e8%aa%9e-%e6%8a%95%e5%bd%b1","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/63814\/","title":{"rendered":"MongoDB\u8853\u8a9e &#8211; \u6295\u5f71"},"content":{"rendered":"<h1 id=\"mongodb%e8%a1%93%e8%aa%9e-%e6%8a%95%e5%bd%b1-FOpreFXlPt\">MongoDB\u8853\u8a9e &#8211; \u6295\u5f71<\/h1>\n<p>\u5728\u4f7f\u7528MongoDB\u9032\u884c\u6578\u64da\u67e5\u8a62\u6642\uff0c\u6295\u5f71\uff08Projection\uff09\u662f\u4e00\u500b\u975e\u5e38\u91cd\u8981\u7684\u6982\u5ff5\u3002\u6295\u5f71\u5141\u8a31\u7528\u6236\u5728\u67e5\u8a62\u4e2d\u6307\u5b9a\u6240\u9700\u7684\u5b57\u6bb5\uff0c\u5f9e\u800c\u63a7\u5236\u8fd4\u56de\u7684\u6578\u64da\u5167\u5bb9\u3002\u9019\u4e0d\u50c5\u53ef\u4ee5\u63d0\u9ad8\u67e5\u8a62\u6548\u7387\uff0c\u9084\u80fd\u6e1b\u5c11\u7db2\u7d61\u50b3\u8f38\u7684\u6578\u64da\u91cf\uff0c\u7279\u5225\u662f\u5728\u8655\u7406\u5927\u578b\u6578\u64da\u96c6\u6642\u3002<\/p>\n<h2 id=\"%e4%bb%80%e9%ba%bc%e6%98%af%e6%8a%95%e5%bd%b1%ef%bc%9f-FOpreFXlPt\">\u4ec0\u9ebc\u662f\u6295\u5f71\uff1f<\/h2>\n<p>\u6295\u5f71\u662f\u6307\u5728\u67e5\u8a62\u4e2d\u9078\u64c7\u7279\u5b9a\u7684\u5b57\u6bb5\u4f86\u8fd4\u56de\uff0c\u800c\u4e0d\u662f\u8fd4\u56de\u6574\u500b\u6587\u6a94\u3002\u9019\u6a23\u505a\u7684\u597d\u8655\u5728\u65bc\uff0c\u7576\u6587\u6a94\u4e2d\u5305\u542b\u5927\u91cf\u4e0d\u5fc5\u8981\u7684\u6578\u64da\u6642\uff0c\u6295\u5f71\u53ef\u4ee5\u5e6b\u52a9\u7528\u6236\u53ea\u7372\u53d6\u6240\u9700\u7684\u4fe1\u606f\u3002<\/p>\n<h2 id=\"%e6%8a%95%e5%bd%b1%e7%9a%84%e5%9f%ba%e6%9c%ac%e7%94%a8%e6%b3%95-FOpreFXlPt\">\u6295\u5f71\u7684\u57fa\u672c\u7528\u6cd5<\/h2>\n<p>\u5728MongoDB\u4e2d\uff0c\u6295\u5f71\u901a\u5e38\u8207\u67e5\u8a62\u64cd\u4f5c\u4e00\u8d77\u4f7f\u7528\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u57fa\u672c\u7684\u67e5\u8a62\u793a\u4f8b\uff0c\u5c55\u793a\u4e86\u5982\u4f55\u4f7f\u7528\u6295\u5f71\u4f86\u9078\u64c7\u7279\u5b9a\u5b57\u6bb5\uff1a<\/p>\n<pre><code>db.collection.find(\n    { \"status\": \"active\" },\n    { \"name\": 1, \"email\": 1, \"_id\": 0 }\n)<\/code><\/pre>\n<p>\u5728\u9019\u500b\u4f8b\u5b50\u4e2d\uff0c\u67e5\u8a62\u5c07\u8fd4\u56de\u6240\u6709\u72c0\u614b\u70ba\u201cactive\u201d\u7684\u6587\u6a94\uff0c\u4f46\u53ea\u6703\u986f\u793a\u201cname\u201d\u548c\u201cemail\u201d\u5b57\u6bb5\uff0c\u800c\u4e0d\u6703\u986f\u793a\u201c_id\u201d\u5b57\u6bb5\u3002\u9019\u88e1\u7684\u201c1\u201d\u8868\u793a\u8981\u8fd4\u56de\u8a72\u5b57\u6bb5\uff0c\u800c\u201c0\u201d\u5247\u8868\u793a\u4e0d\u8fd4\u56de\u8a72\u5b57\u6bb5\u3002<\/p>\n<h2 id=\"%e6%8a%95%e5%bd%b1%e7%9a%84%e9%80%b2%e9%9a%8e%e7%94%a8%e6%b3%95-FOpreFXlPt\">\u6295\u5f71\u7684\u9032\u968e\u7528\u6cd5<\/h2>\n<p>\u9664\u4e86\u57fa\u672c\u7684\u5b57\u6bb5\u9078\u64c7\uff0cMongoDB\u7684\u6295\u5f71\u9084\u652f\u6301\u4e00\u4e9b\u9032\u968e\u529f\u80fd\uff0c\u4f8b\u5982\u5d4c\u5957\u5b57\u6bb5\u7684\u9078\u64c7\u548c\u8a08\u7b97\u5b57\u6bb5\u7684\u4f7f\u7528\u3002<\/p>\n<h3 id=\"%e5%b5%8c%e5%a5%97%e5%ad%97%e6%ae%b5%e7%9a%84%e9%81%b8%e6%93%87-FOpreFXlPt\">\u5d4c\u5957\u5b57\u6bb5\u7684\u9078\u64c7<\/h3>\n<p>\u5982\u679c\u6587\u6a94\u4e2d\u5305\u542b\u5d4c\u5957\u7d50\u69cb\uff0c\u6295\u5f71\u4e5f\u53ef\u4ee5\u7528\u4f86\u9078\u64c7\u5d4c\u5957\u5b57\u6bb5\u3002\u4f8b\u5982\uff1a<\/p>\n<pre><code>db.collection.find(\n    {},\n    { \"address.city\": 1, \"address.zip\": 1 }\n)<\/code><\/pre>\n<p>\u9019\u500b\u67e5\u8a62\u5c07\u8fd4\u56de\u6240\u6709\u6587\u6a94\u7684\u201caddress\u201d\u5b57\u6bb5\u4e2d\u7684\u201ccity\u201d\u548c\u201czip\u201d\u4fe1\u606f\u3002<\/p>\n<h3 id=\"%e8%a8%88%e7%ae%97%e5%ad%97%e6%ae%b5%e7%9a%84%e4%bd%bf%e7%94%a8-FOpreFXlPt\">\u8a08\u7b97\u5b57\u6bb5\u7684\u4f7f\u7528<\/h3>\n<p>MongoDB\u9084\u652f\u6301\u4f7f\u7528\u805a\u5408\u7ba1\u9053\u4f86\u9032\u884c\u66f4\u8907\u96dc\u7684\u8a08\u7b97\u548c\u8f49\u63db\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u4f7f\u7528\u805a\u5408\u7ba1\u9053\u7684\u793a\u4f8b\uff1a<\/p>\n<pre><code>db.collection.aggregate([\n    { $match: { \"status\": \"active\" } },\n    { $project: { \"name\": 1, \"email\": 1, \"year\": { $year: \"$createdAt\" } } }\n])<\/code><\/pre>\n<p>\u5728\u9019\u500b\u4f8b\u5b50\u4e2d\uff0c\u67e5\u8a62\u4e0d\u50c5\u8fd4\u56de\u201cname\u201d\u548c\u201cemail\u201d\u5b57\u6bb5\uff0c\u9084\u8a08\u7b97\u4e86\u201ccreatedAt\u201d\u5b57\u6bb5\u7684\u5e74\u4efd\u3002<\/p>\n<h2 id=\"%e6%8a%95%e5%bd%b1%e7%9a%84%e6%b3%a8%e6%84%8f%e4%ba%8b%e9%a0%85-FOpreFXlPt\">\u6295\u5f71\u7684\u6ce8\u610f\u4e8b\u9805<\/h2>\n<p>\u5728\u4f7f\u7528\u6295\u5f71\u6642\uff0c\u6709\u5e7e\u500b\u6ce8\u610f\u4e8b\u9805\u9700\u8981\u8003\u616e\uff1a<\/p>\n<ul>\n<li>\u5982\u679c\u8981\u6392\u9664\u67d0\u4e9b\u5b57\u6bb5\uff0c\u5fc5\u9808\u540c\u6642\u5305\u542b\u201c_id\u201d\u5b57\u6bb5\u7684\u6392\u9664\uff0c\u56e0\u70baMongoDB\u9ed8\u8a8d\u6703\u8fd4\u56de\u201c_id\u201d\u3002<\/li>\n<li>\u6295\u5f71\u4e0d\u652f\u6301\u8fd4\u56de\u8a08\u7b97\u5b57\u6bb5\u548c\u539f\u59cb\u5b57\u6bb5\u7684\u6df7\u5408\uff0c\u5fc5\u9808\u9078\u64c7\u4e00\u7a2e\u65b9\u5f0f\u3002<\/li>\n<li>\u904e\u5ea6\u4f7f\u7528\u6295\u5f71\u53ef\u80fd\u6703\u5c0e\u81f4\u67e5\u8a62\u6027\u80fd\u4e0b\u964d\uff0c\u7279\u5225\u662f\u5728\u9700\u8981\u9032\u884c\u591a\u6b21\u67e5\u8a62\u7684\u60c5\u6cc1\u4e0b\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b8%bd%e7%b5%90-FOpreFXlPt\">\u7e3d\u7d50<\/h2>\n<p>\u6295\u5f71\u662fMongoDB\u4e2d\u4e00\u500b\u5f37\u5927\u7684\u529f\u80fd\uff0c\u80fd\u5920\u5e6b\u52a9\u7528\u6236\u7cbe\u78ba\u63a7\u5236\u67e5\u8a62\u7d50\u679c\u7684\u5167\u5bb9\u3002\u901a\u904e\u5408\u7406\u4f7f\u7528\u6295\u5f71\uff0c\u53ef\u4ee5\u63d0\u9ad8\u67e5\u8a62\u6548\u7387\uff0c\u6e1b\u5c11\u4e0d\u5fc5\u8981\u7684\u6578\u64da\u50b3\u8f38\u3002\u5728\u9078\u64c7\u5408\u9069\u7684 <a href=\"https:\/\/server.hk\">VPS<\/a> \u89e3\u6c7a\u65b9\u6848\u6642\uff0c\u4e86\u89e3\u5982\u4f55\u6709\u6548\u4f7f\u7528MongoDB\u7684\u6295\u5f71\u529f\u80fd\u5c07\u5c0d\u6578\u64da\u7ba1\u7406\u548c\u61c9\u7528\u958b\u767c\u5927\u6709\u88e8\u76ca\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4e86\u89e3MongoDB\u4e2d\u7684\u6295\u5f71\u8853\u8a9e\uff0c\u5b78\u7fd2\u5982\u4f55\u9078\u64c7\u67e5\u8a62\u7d50\u679c\u4e2d\u7684\u7279\u5b9a\u5b57\u6bb5\u4ee5\u512a\u5316\u6578\u64da\u6aa2\u7d22\u6548\u7387\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-63814","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/63814","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=63814"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/63814\/revisions"}],"predecessor-version":[{"id":63815,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/63814\/revisions\/63815"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=63814"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=63814"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=63814"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}