{"id":172821,"date":"2024-11-07T15:20:18","date_gmt":"2024-11-07T07:20:18","guid":{"rendered":"https:\/\/server.hk\/cnblog\/172821\/"},"modified":"2024-11-07T15:20:19","modified_gmt":"2024-11-07T07:20:19","slug":"%e5%a6%82%e4%bd%95%e6%9f%a5%e8%a9%a2%e6%95%b8%e6%93%9a%e5%ba%ab%e4%b8%ad%e7%9a%84%e7%89%b9%e5%ae%9a%e8%a1%8c%e6%95%b8%e6%93%9a%ef%bc%9f-%e6%9f%a5%e8%a9%a2%e6%95%b8%e6%93%9a%e5%ba%ab%e6%8c%87%e5%ae%9a","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/172821\/","title":{"rendered":"\u5982\u4f55\u67e5\u8a62\u6578\u64da\u5eab\u4e2d\u7684\u7279\u5b9a\u884c\u6578\u64da\uff1f (\u67e5\u8a62\u6578\u64da\u5eab\u6307\u5b9a\u884c\u6578\u64da)"},"content":{"rendered":"<h1 id=\"%e5%a6%82%e4%bd%95%e6%9f%a5%e8%a9%a2%e6%95%b8%e6%93%9a%e5%ba%ab%e4%b8%ad%e7%9a%84%e7%89%b9%e5%ae%9a%e8%a1%8c%e6%95%b8%e6%93%9a%ef%bc%9f-gfkxbGqTRF\">\u5982\u4f55\u67e5\u8a62\u6578\u64da\u5eab\u4e2d\u7684\u7279\u5b9a\u884c\u6578\u64da\uff1f<\/h1>\n<p>\u5728\u6578\u64da\u5eab\u7ba1\u7406\u4e2d\uff0c\u67e5\u8a62\u7279\u5b9a\u884c\u6578\u64da\u662f\u4e00\u9805\u57fa\u672c\u800c\u91cd\u8981\u7684\u6280\u80fd\u3002\u7121\u8ad6\u662f\u4f7f\u7528\u95dc\u806f\u6578\u64da\u5eab\u5982 MySQL\u3001PostgreSQL\uff0c\u9084\u662f NoSQL \u6578\u64da\u5eab\u5982 MongoDB\uff0c\u4e86\u89e3\u5982\u4f55\u6709\u6548\u5730\u67e5\u8a62\u6578\u64da\u90fd\u662f\u81f3\u95dc\u91cd\u8981\u7684\u3002\u672c\u6587\u5c07\u4ecb\u7d39\u5982\u4f55\u5728\u4e0d\u540c\u985e\u578b\u7684\u6578\u64da\u5eab\u4e2d\u67e5\u8a62\u7279\u5b9a\u884c\u6578\u64da\uff0c\u4e26\u63d0\u4f9b\u76f8\u61c9\u7684\u793a\u4f8b\u548c\u4ee3\u78bc\u7247\u6bb5\u3002<\/p>\n<h2 id=\"%e9%97%9c%e8%81%af%e6%95%b8%e6%93%9a%e5%ba%ab%e4%b8%ad%e7%9a%84%e6%9f%a5%e8%a9%a2-gfkxbGqTRF\">\u95dc\u806f\u6578\u64da\u5eab\u4e2d\u7684\u67e5\u8a62<\/h2>\n<p>\u5728\u95dc\u806f\u6578\u64da\u5eab\u4e2d\uff0c\u67e5\u8a62\u7279\u5b9a\u884c\u6578\u64da\u901a\u5e38\u4f7f\u7528 SQL\uff08\u7d50\u69cb\u5316\u67e5\u8a62\u8a9e\u8a00\uff09\u3002\u4ee5\u4e0b\u662f\u4e00\u4e9b\u57fa\u672c\u7684 SQL \u67e5\u8a62\u8a9e\u53e5\u793a\u4f8b\uff1a<\/p>\n<h3 id=\"%e4%bd%bf%e7%94%a8-select-%e8%aa%9e%e5%8f%a5-gfkxbGqTRF\">\u4f7f\u7528 SELECT \u8a9e\u53e5<\/h3>\n<p>\u6700\u5e38\u898b\u7684\u67e5\u8a62\u65b9\u5f0f\u662f\u4f7f\u7528 <code>SELECT<\/code> \u8a9e\u53e5\u3002\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u540d\u70ba <code>employees<\/code> \u7684\u8868\uff0c\u4e26\u5e0c\u671b\u67e5\u8a62\u7279\u5b9a\u54e1\u5de5\u7684\u6578\u64da\uff1a<\/p>\n<pre><code>SELECT * FROM employees WHERE employee_id = 1;<\/code><\/pre>\n<p>\u9019\u689d\u8a9e\u53e5\u5c07\u8fd4\u56de <code>employee_id<\/code> \u70ba 1 \u7684\u6240\u6709\u884c\u6578\u64da\u3002\u5982\u679c\u53ea\u9700\u8981\u7279\u5b9a\u7684\u5217\uff0c\u53ef\u4ee5\u9019\u6a23\u5beb\uff1a<\/p>\n<pre><code>SELECT first_name, last_name FROM employees WHERE employee_id = 1;<\/code><\/pre>\n<h3 id=\"%e4%bd%bf%e7%94%a8-limit-%e9%99%90%e5%88%b6%e8%a1%8c%e6%95%b8-gfkxbGqTRF\">\u4f7f\u7528 LIMIT \u9650\u5236\u884c\u6578<\/h3>\n<p>\u5982\u679c\u9700\u8981\u67e5\u8a62\u7279\u5b9a\u6578\u91cf\u7684\u884c\uff0c\u53ef\u4ee5\u4f7f\u7528 <code>LIMIT<\/code> \u5b50\u53e5\u3002\u4f8b\u5982\uff0c\u67e5\u8a62\u524d 5 \u540d\u54e1\u5de5\u7684\u6578\u64da\uff1a<\/p>\n<pre><code>SELECT * FROM employees LIMIT 5;<\/code><\/pre>\n<h2 id=\"nosql-%e6%95%b8%e6%93%9a%e5%ba%ab%e4%b8%ad%e7%9a%84%e6%9f%a5%e8%a9%a2-gfkxbGqTRF\">NoSQL \u6578\u64da\u5eab\u4e2d\u7684\u67e5\u8a62<\/h2>\n<p>\u5728 NoSQL \u6578\u64da\u5eab\u4e2d\uff0c\u67e5\u8a62\u7684\u65b9\u5f0f\u6703\u6709\u6240\u4e0d\u540c\u3002\u4ee5 MongoDB \u70ba\u4f8b\uff0c\u67e5\u8a62\u7279\u5b9a\u884c\u6578\u64da\u7684\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n<h3 id=\"%e4%bd%bf%e7%94%a8-find-%e6%96%b9%e6%b3%95-gfkxbGqTRF\">\u4f7f\u7528 find() \u65b9\u6cd5<\/h3>\n<p>\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u540d\u70ba <code>employees<\/code> \u7684\u96c6\u5408\uff0c\u4e26\u5e0c\u671b\u67e5\u8a62\u7279\u5b9a\u54e1\u5de5\u7684\u6578\u64da\uff1a<\/p>\n<pre><code>db.employees.find({ employee_id: 1 });<\/code><\/pre>\n<p>\u9019\u689d\u8a9e\u53e5\u5c07\u8fd4\u56de <code>employee_id<\/code> \u70ba 1 \u7684\u6240\u6709\u6587\u6a94\u3002\u5982\u679c\u53ea\u9700\u8981\u7279\u5b9a\u7684\u5b57\u6bb5\uff0c\u53ef\u4ee5\u9019\u6a23\u5beb\uff1a<\/p>\n<pre><code>db.employees.find({ employee_id: 1 }, { first_name: 1, last_name: 1 });<\/code><\/pre>\n<h3 id=\"%e4%bd%bf%e7%94%a8-limit-%e9%99%90%e5%88%b6%e6%96%87%e6%aa%94%e6%95%b8%e9%87%8f-gfkxbGqTRF\">\u4f7f\u7528 limit() \u9650\u5236\u6587\u6a94\u6578\u91cf<\/h3>\n<p>\u5728 MongoDB \u4e2d\uff0c\u5982\u679c\u9700\u8981\u67e5\u8a62\u7279\u5b9a\u6578\u91cf\u7684\u6587\u6a94\uff0c\u53ef\u4ee5\u4f7f\u7528 <code>limit()<\/code> \u65b9\u6cd5\u3002\u4f8b\u5982\uff0c\u67e5\u8a62\u524d 5 \u540d\u54e1\u5de5\u7684\u6578\u64da\uff1a<\/p>\n<pre><code>db.employees.find().limit(5);<\/code><\/pre>\n<h2 id=\"%e6%9f%a5%e8%a9%a2%e6%80%a7%e8%83%bd%e5%84%aa%e5%8c%96-gfkxbGqTRF\">\u67e5\u8a62\u6027\u80fd\u512a\u5316<\/h2>\n<p>\u5728\u67e5\u8a62\u6578\u64da\u6642\uff0c\u6027\u80fd\u662f\u9700\u8981\u8003\u616e\u7684\u91cd\u8981\u56e0\u7d20\u3002\u4ee5\u4e0b\u662f\u4e00\u4e9b\u512a\u5316\u67e5\u8a62\u6027\u80fd\u7684\u5efa\u8b70\uff1a<\/p>\n<ul>\n<li><strong>\u4f7f\u7528\u7d22\u5f15\uff1a<\/strong>\u70ba\u5e38\u7528\u7684\u67e5\u8a62\u689d\u4ef6\u5efa\u7acb\u7d22\u5f15\uff0c\u53ef\u4ee5\u986f\u8457\u63d0\u9ad8\u67e5\u8a62\u901f\u5ea6\u3002<\/li>\n<li><strong>\u907f\u514d SELECT *\uff1a<\/strong>\u53ea\u67e5\u8a62\u9700\u8981\u7684\u5217\uff0c\u6e1b\u5c11\u6578\u64da\u50b3\u8f38\u91cf\u3002<\/li>\n<li><strong>\u4f7f\u7528\u5408\u9069\u7684\u6578\u64da\u985e\u578b\uff1a<\/strong>\u9078\u64c7\u5408\u9069\u7684\u6578\u64da\u985e\u578b\u53ef\u4ee5\u63d0\u9ad8\u5b58\u5132\u6548\u7387\u548c\u67e5\u8a62\u6027\u80fd\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b8%bd%e7%b5%90-gfkxbGqTRF\">\u7e3d\u7d50<\/h2>\n<p>\u67e5\u8a62\u6578\u64da\u5eab\u4e2d\u7684\u7279\u5b9a\u884c\u6578\u64da\u662f\u6578\u64da\u5eab\u7ba1\u7406\u7684\u57fa\u672c\u6280\u80fd\uff0c\u7121\u8ad6\u662f\u5728\u95dc\u806f\u6578\u64da\u5eab\u9084\u662f NoSQL \u6578\u64da\u5eab\u4e2d\uff0c\u638c\u63e1\u76f8\u61c9\u7684\u67e5\u8a62\u8a9e\u6cd5\u548c\u6280\u5de7\u90fd\u80fd\u63d0\u9ad8\u5de5\u4f5c\u6548\u7387\u3002\u900f\u904e\u4f7f\u7528 <code>SELECT<\/code> \u548c <code>find()<\/code> \u7b49\u8a9e\u53e5\uff0c\u4e26\u7d50\u5408\u6027\u80fd\u512a\u5316\u7b56\u7565\uff0c\u53ef\u4ee5\u6709\u6548\u5730\u7372\u53d6\u6240\u9700\u7684\u6578\u64da\u3002<\/p>\n<p>\u5982\u679c\u60a8\u6b63\u5728\u5c0b\u627e\u9ad8\u6548\u7684 <a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a> \u89e3\u6c7a\u65b9\u6848\uff0cServer.HK \u63d0\u4f9b\u591a\u7a2e\u9078\u64c7\uff0c\u6eff\u8db3\u4e0d\u540c\u7528\u6236\u7684\u9700\u6c42\u3002\u7121\u8ad6\u662f\u6578\u64da\u5eab\u7ba1\u7406\u9084\u662f\u5176\u4ed6\u61c9\u7528\uff0c\u9078\u64c7\u5408\u9069\u7684 <a href=\"https:\/\/server.hk\">\u4f3a\u670d\u5668<\/a> \u5c07\u6709\u52a9\u65bc\u63d0\u5347\u60a8\u7684\u696d\u52d9\u6548\u7387\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u5b78\u7fd2\u5982\u4f55\u5728\u6578\u64da\u5eab\u4e2d\u67e5\u8a62\u7279\u5b9a\u884c\u7684\u6578\u64da\uff0c\u638c\u63e1SQL\u8a9e\u53e5\u548c\u67e5\u8a62\u6280\u5de7\uff0c\u8f15\u9b06\u7372\u53d6\u6240\u9700\u4fe1\u606f\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-172821","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/172821","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=172821"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/172821\/revisions"}],"predecessor-version":[{"id":172822,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/172821\/revisions\/172822"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=172821"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=172821"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=172821"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}