{"id":179860,"date":"2024-11-09T05:24:19","date_gmt":"2024-11-08T21:24:19","guid":{"rendered":"https:\/\/server.hk\/cnblog\/179860\/"},"modified":"2024-11-09T05:24:20","modified_gmt":"2024-11-08T21:24:20","slug":"%e5%a6%82%e4%bd%95%e5%9c%a8%e6%95%b8%e6%93%9a%e5%ba%ab%e4%b8%ad%e5%88%a9%e7%94%a8-unique-%e5%b1%ac%e6%80%a7%e5%af%a6%e7%8f%be%e6%95%b8%e6%93%9a%e5%94%af%e4%b8%80%e6%80%a7%ef%bc%9f-unique-%e6%80%8e","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/179860\/","title":{"rendered":"\u5982\u4f55\u5728\u6578\u64da\u5eab\u4e2d\u5229\u7528 unique \u5c6c\u6027\u5be6\u73fe\u6578\u64da\u552f\u4e00\u6027\uff1f (unique \u600e\u9ebc\u7528\u5728\u6578\u64da\u5eab\u4e2d)"},"content":{"rendered":"<h1 id=\"%e5%a6%82%e4%bd%95%e5%9c%a8%e6%95%b8%e6%93%9a%e5%ba%ab%e4%b8%ad%e5%88%a9%e7%94%a8-unique-%e5%b1%ac%e6%80%a7%e5%af%a6%e7%8f%be%e6%95%b8%e6%93%9a%e5%94%af%e4%b8%80%e6%80%a7%ef%bc%9f-ToeHcsoxKQ\">\u5982\u4f55\u5728\u6578\u64da\u5eab\u4e2d\u5229\u7528 unique \u5c6c\u6027\u5be6\u73fe\u6578\u64da\u552f\u4e00\u6027\uff1f<\/h1>\n<p>\u5728\u73fe\u4ee3\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\u4e2d\uff0c\u78ba\u4fdd\u6578\u64da\u7684\u552f\u4e00\u6027\u662f\u975e\u5e38\u91cd\u8981\u7684\u3002\u9019\u4e0d\u50c5\u80fd\u5920\u907f\u514d\u6578\u64da\u91cd\u8907\uff0c\u9084\u80fd\u63d0\u9ad8\u6578\u64da\u7684\u5b8c\u6574\u6027\u548c\u53ef\u9760\u6027\u3002\u70ba\u4e86\u5be6\u73fe\u9019\u4e00\u76ee\u6a19\uff0c\u6578\u64da\u5eab\u63d0\u4f9b\u4e86\u591a\u7a2e\u6a5f\u5236\uff0c\u5176\u4e2d\u6700\u5e38\u7528\u7684\u5c31\u662f unique \u5c6c\u6027\u3002\u672c\u6587\u5c07\u6df1\u5165\u63a2\u8a0e\u5982\u4f55\u5728\u6578\u64da\u5eab\u4e2d\u5229\u7528 unique \u5c6c\u6027\u4f86\u5be6\u73fe\u6578\u64da\u7684\u552f\u4e00\u6027\u3002<\/p>\n<h2 id=\"%e4%bb%80%e9%ba%bc%e6%98%af-unique-%e5%b1%ac%e6%80%a7%ef%bc%9f-ToeHcsoxKQ\">\u4ec0\u9ebc\u662f unique \u5c6c\u6027\uff1f<\/h2>\n<p>unique \u5c6c\u6027\u662f\u4e00\u7a2e\u7d04\u675f\u689d\u4ef6\uff0c\u7528\u65bc\u78ba\u4fdd\u6578\u64da\u8868\u4e2d\u7684\u67d0\u4e00\u5217\u6216\u591a\u5217\u7684\u503c\u662f\u552f\u4e00\u7684\u3002\u9019\u610f\u5473\u8457\u5728\u540c\u4e00\u5217\u4e2d\uff0c\u4e0d\u80fd\u6709\u5169\u884c\u64c1\u6709\u76f8\u540c\u7684\u503c\u3002unique \u5c6c\u6027\u901a\u5e38\u7528\u65bc\u4e3b\u9375\u4ee5\u5916\u7684\u5217\uff0c\u9019\u6a23\u53ef\u4ee5\u5728\u4e0d\u5f71\u97ff\u4e3b\u9375\u7684\u60c5\u6cc1\u4e0b\uff0c\u4fdd\u6301\u5176\u4ed6\u5217\u7684\u6578\u64da\u552f\u4e00\u6027\u3002<\/p>\n<h2 id=\"%e5%a6%82%e4%bd%95%e4%bd%bf%e7%94%a8-unique-%e5%b1%ac%e6%80%a7%ef%bc%9f-ToeHcsoxKQ\">\u5982\u4f55\u4f7f\u7528 unique \u5c6c\u6027\uff1f<\/h2>\n<p>\u5728 SQL \u4e2d\uff0c\u4f7f\u7528 unique \u5c6c\u6027\u975e\u5e38\u7c21\u55ae\u3002\u4ee5\u4e0b\u662f\u4e00\u4e9b\u5e38\u898b\u7684\u7528\u6cd5\u793a\u4f8b\uff1a<\/p>\n<h3 id=\"1-%e5%89%b5%e5%bb%ba%e8%a1%a8%e6%99%82%e8%a8%ad%e7%bd%ae-unique-%e5%b1%ac%e6%80%a7-ToeHcsoxKQ\">1. \u5275\u5efa\u8868\u6642\u8a2d\u7f6e unique \u5c6c\u6027<\/h3>\n<pre><code>CREATE TABLE users (\n    id INT PRIMARY KEY,\n    email VARCHAR(255) UNIQUE,\n    username VARCHAR(50) UNIQUE\n);<\/code><\/pre>\n<p>\u5728\u9019\u500b\u4f8b\u5b50\u4e2d\uff0cemail \u548c username \u5217\u90fd\u88ab\u8a2d\u7f6e\u70ba unique\uff0c\u9019\u610f\u5473\u8457\u6bcf\u500b\u7528\u6236\u7684\u96fb\u5b50\u90f5\u4ef6\u548c\u7528\u6236\u540d\u5fc5\u9808\u662f\u552f\u4e00\u7684\u3002<\/p>\n<h3 id=\"2-%e5%9c%a8%e5%b7%b2%e5%ad%98%e5%9c%a8%e7%9a%84%e8%a1%a8%e4%b8%ad%e6%b7%bb%e5%8a%a0-unique-%e7%b4%84%e6%9d%9f-ToeHcsoxKQ\">2. \u5728\u5df2\u5b58\u5728\u7684\u8868\u4e2d\u6dfb\u52a0 unique \u7d04\u675f<\/h3>\n<pre><code>ALTER TABLE users\nADD CONSTRAINT unique_email UNIQUE (email);<\/code><\/pre>\n<p>\u5982\u679c\u4f60\u5df2\u7d93\u6709\u4e00\u500b\u8868\u4e26\u5e0c\u671b\u5728\u67d0\u4e00\u5217\u4e0a\u6dfb\u52a0 unique \u7d04\u675f\uff0c\u53ef\u4ee5\u4f7f\u7528 ALTER TABLE \u8a9e\u53e5\u3002\u9019\u6a23\u53ef\u4ee5\u78ba\u4fdd\u672a\u4f86\u63d2\u5165\u7684\u6578\u64da\u4e0d\u6703\u9055\u53cd\u552f\u4e00\u6027\u7d04\u675f\u3002<\/p>\n<h3 id=\"3-%e4%bd%bf%e7%94%a8%e5%a4%9a%e5%88%97-unique-%e7%b4%84%e6%9d%9f-ToeHcsoxKQ\">3. \u4f7f\u7528\u591a\u5217 unique \u7d04\u675f<\/h3>\n<pre><code>CREATE TABLE orders (\n    order_id INT PRIMARY KEY,\n    user_id INT,\n    product_id INT,\n    UNIQUE (user_id, product_id)\n);<\/code><\/pre>\n<p>\u5728\u9019\u500b\u4f8b\u5b50\u4e2d\uff0cuser_id \u548c product_id \u7684\u7d44\u5408\u88ab\u8a2d\u7f6e\u70ba unique\u3002\u9019\u610f\u5473\u8457\u540c\u4e00\u7528\u6236\u4e0d\u80fd\u5c0d\u540c\u4e00\u7522\u54c1\u4e0b\u591a\u500b\u8a02\u55ae\u3002<\/p>\n<h2 id=\"unique-%e5%b1%ac%e6%80%a7%e7%9a%84%e5%84%aa%e5%8b%a2-ToeHcsoxKQ\">unique \u5c6c\u6027\u7684\u512a\u52e2<\/h2>\n<ul>\n<li><strong>\u6578\u64da\u5b8c\u6574\u6027\uff1a<\/strong>\u78ba\u4fdd\u6578\u64da\u7684\u552f\u4e00\u6027\u53ef\u4ee5\u9632\u6b62\u91cd\u8907\u6578\u64da\u7684\u51fa\u73fe\uff0c\u5f9e\u800c\u63d0\u9ad8\u6578\u64da\u7684\u5b8c\u6574\u6027\u3002<\/li>\n<li><strong>\u67e5\u8a62\u6548\u7387\uff1a<\/strong>\u4f7f\u7528 unique \u7d04\u675f\u53ef\u4ee5\u63d0\u9ad8\u67e5\u8a62\u7684\u6548\u7387\uff0c\u56e0\u70ba\u6578\u64da\u5eab\u53ef\u4ee5\u66f4\u5feb\u5730\u5b9a\u4f4d\u5230\u552f\u4e00\u7684\u6578\u64da\u884c\u3002<\/li>\n<li><strong>\u6578\u64da\u4e00\u81f4\u6027\uff1a<\/strong>\u901a\u904e\u5f37\u5236\u57f7\u884c\u552f\u4e00\u6027\u7d04\u675f\uff0c\u53ef\u4ee5\u78ba\u4fdd\u6578\u64da\u7684\u4e00\u81f4\u6027\uff0c\u6e1b\u5c11\u932f\u8aa4\u7684\u767c\u751f\u3002<\/li>\n<\/ul>\n<h2 id=\"%e6%b3%a8%e6%84%8f%e4%ba%8b%e9%a0%85-ToeHcsoxKQ\">\u6ce8\u610f\u4e8b\u9805<\/h2>\n<p>\u5728\u4f7f\u7528 unique \u5c6c\u6027\u6642\uff0c\u9700\u8981\u6ce8\u610f\u4ee5\u4e0b\u5e7e\u9ede\uff1a<\/p>\n<ul>\n<li>\u5728\u63d2\u5165\u6578\u64da\u6642\uff0c\u5982\u679c\u9055\u53cd\u4e86 unique \u7d04\u675f\uff0c\u6578\u64da\u5eab\u5c07\u8fd4\u56de\u932f\u8aa4\uff0c\u4e26\u4e14\u8a72\u884c\u6578\u64da\u5c07\u4e0d\u6703\u88ab\u63d2\u5165\u3002<\/li>\n<li>unique \u7d04\u675f\u53ef\u4ee5\u8207 NULL \u503c\u4e00\u8d77\u4f7f\u7528\uff0c\u4f46\u6bcf\u500b\u5217\u53ea\u80fd\u6709\u4e00\u500b NULL \u503c\uff0c\u56e0\u70ba NULL \u88ab\u8996\u70ba\u4e0d\u7b49\u65bc\u4efb\u4f55\u503c\u3002<\/li>\n<li>\u5728\u8a2d\u8a08\u6578\u64da\u5eab\u6642\uff0c\u61c9\u8b39\u614e\u9078\u64c7\u9700\u8981\u8a2d\u7f6e unique \u7d04\u675f\u7684\u5217\uff0c\u4ee5\u907f\u514d\u4e0d\u5fc5\u8981\u7684\u932f\u8aa4\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b8%bd%e7%b5%90-ToeHcsoxKQ\">\u7e3d\u7d50<\/h2>\n<p>\u5229\u7528 unique \u5c6c\u6027\u4f86\u5be6\u73fe\u6578\u64da\u7684\u552f\u4e00\u6027\u662f\u6578\u64da\u5eab\u8a2d\u8a08\u4e2d\u7684\u4e00\u500b\u91cd\u8981\u65b9\u9762\u3002\u901a\u904e\u6b63\u78ba\u5730\u4f7f\u7528 unique \u7d04\u675f\uff0c\u53ef\u4ee5\u63d0\u9ad8\u6578\u64da\u7684\u5b8c\u6574\u6027\u548c\u4e00\u81f4\u6027\uff0c\u4e26\u4e14\u5728\u67e5\u8a62\u6642\u80fd\u5920\u7372\u5f97\u66f4\u597d\u7684\u6027\u80fd\u3002\u7121\u8ad6\u662f\u5728\u5275\u5efa\u65b0\u8868\u9084\u662f\u4fee\u6539\u73fe\u6709\u8868\u6642\uff0c\u5408\u7406\u5730\u8a2d\u7f6e unique \u5c6c\u6027\u90fd\u662f\u4e00\u500b\u826f\u597d\u7684\u5be6\u8e10\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\u60a8\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\">\u9999\u6e2f\u4f3a\u670d\u5668<\/a> \u5c07\u6709\u52a9\u65bc\u63d0\u5347\u60a8\u7684\u696d\u52d9\u6548\u7387\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4e86\u89e3\u5982\u4f55\u5728\u6578\u64da\u5eab\u4e2d\u4f7f\u7528 unique \u5c6c\u6027\u78ba\u4fdd\u6578\u64da\u552f\u4e00\u6027\uff0c\u907f\u514d\u91cd\u8907\u8a18\u9304\uff0c\u63d0\u9ad8\u6578\u64da\u5b8c\u6574\u6027\u548c\u67e5\u8a62\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-179860","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/179860","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=179860"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/179860\/revisions"}],"predecessor-version":[{"id":179861,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/179860\/revisions\/179861"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=179860"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=179860"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=179860"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}