{"id":79336,"date":"2024-10-16T12:59:14","date_gmt":"2024-10-16T04:59:14","guid":{"rendered":"https:\/\/server.hk\/cnblog\/79336\/"},"modified":"2024-10-16T12:59:15","modified_gmt":"2024-10-16T04:59:15","slug":"mysql%e6%8c%87%e4%bb%a4-on-update%ef%bc%88%e6%9b%b4%e6%96%b0%e6%99%82%ef%bc%89","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/79336\/","title":{"rendered":"MySQL\u6307\u4ee4: ON UPDATE\uff08\u66f4\u65b0\u6642\uff09"},"content":{"rendered":"<h1 id=\"mysql%e6%8c%87%e4%bb%a4-on-update%ef%bc%88%e6%9b%b4%e6%96%b0%e6%99%82%ef%bc%89-vciCBkbtcm\">MySQL\u6307\u4ee4: ON UPDATE\uff08\u66f4\u65b0\u6642\uff09<\/h1>\n<p>\u5728\u8cc7\u6599\u5eab\u7ba1\u7406\u7cfb\u7d71\u4e2d\uff0cMySQL\u662f\u4e00\u500b\u5ee3\u6cdb\u4f7f\u7528\u7684\u958b\u6e90\u95dc\u806f\u8cc7\u6599\u5eab\u7ba1\u7406\u7cfb\u7d71\u3002\u5b83\u63d0\u4f9b\u4e86\u591a\u7a2e\u529f\u80fd\u4f86\u7ba1\u7406\u548c\u64cd\u4f5c\u8cc7\u6599\uff0c\u5176\u4e2d\u4e4b\u4e00\u5c31\u662f\u5916\u9375\u7d04\u675f\u3002\u5916\u9375\u7d04\u675f\u4e0d\u50c5\u80fd\u5920\u78ba\u4fdd\u8cc7\u6599\u7684\u5b8c\u6574\u6027\uff0c\u9084\u80fd\u5920\u5728\u8cc7\u6599\u66f4\u65b0\u6642\u81ea\u52d5\u57f7\u884c\u7279\u5b9a\u7684\u64cd\u4f5c\u3002\u672c\u6587\u5c07\u6df1\u5165\u63a2\u8a0eMySQL\u4e2d\u7684ON UPDATE\u6307\u4ee4\uff0c\u4e26\u63d0\u4f9b\u76f8\u95dc\u7684\u7bc4\u4f8b\u548c\u61c9\u7528\u5834\u666f\u3002<\/p>\n<h2 id=\"%e4%bb%80%e9%ba%bc%e6%98%afon-update%ef%bc%9f-vciCBkbtcm\">\u4ec0\u9ebc\u662fON UPDATE\uff1f<\/h2>\n<p>ON UPDATE\u662f\u4e00\u500b\u7528\u65bc\u5b9a\u7fa9\u5916\u9375\u7d04\u675f\u7684\u6307\u4ee4\uff0c\u7576\u4e3b\u8868\u4e2d\u7684\u8cc7\u6599\u88ab\u66f4\u65b0\u6642\uff0c\u9019\u500b\u6307\u4ee4\u6703\u6c7a\u5b9a\u5982\u4f55\u8655\u7406\u8207\u4e4b\u76f8\u95dc\u7684\u5f9e\u8868\u8cc7\u6599\u3002\u9019\u5c0d\u65bc\u4fdd\u6301\u8cc7\u6599\u7684\u4e00\u81f4\u6027\u548c\u5b8c\u6574\u6027\u81f3\u95dc\u91cd\u8981\u3002ON UPDATE\u53ef\u4ee5\u8207\u4ee5\u4e0b\u9078\u9805\u4e00\u8d77\u4f7f\u7528\uff1a<\/p>\n<ul>\n<li><strong>CASCADE<\/strong>: \u7576\u4e3b\u8868\u4e2d\u7684\u8cc7\u6599\u88ab\u66f4\u65b0\u6642\uff0c\u5f9e\u8868\u4e2d\u76f8\u61c9\u7684\u8cc7\u6599\u4e5f\u6703\u81ea\u52d5\u66f4\u65b0\u3002<\/li>\n<li><strong>SET NULL<\/strong>: \u7576\u4e3b\u8868\u4e2d\u7684\u8cc7\u6599\u88ab\u66f4\u65b0\u6642\uff0c\u5f9e\u8868\u4e2d\u76f8\u61c9\u7684\u5916\u9375\u6b04\u4f4d\u6703\u88ab\u8a2d\u7f6e\u70baNULL\u3002<\/li>\n<li><strong>SET DEFAULT<\/strong>: \u7576\u4e3b\u8868\u4e2d\u7684\u8cc7\u6599\u88ab\u66f4\u65b0\u6642\uff0c\u5f9e\u8868\u4e2d\u76f8\u61c9\u7684\u5916\u9375\u6b04\u4f4d\u6703\u88ab\u8a2d\u7f6e\u70ba\u9810\u8a2d\u503c\u3002<\/li>\n<li><strong>NO ACTION<\/strong>: \u7576\u4e3b\u8868\u4e2d\u7684\u8cc7\u6599\u88ab\u66f4\u65b0\u6642\uff0c\u5982\u679c\u5f9e\u8868\u4e2d\u5b58\u5728\u76f8\u95dc\u8cc7\u6599\uff0c\u5247\u4e0d\u57f7\u884c\u4efb\u4f55\u64cd\u4f5c\uff0c\u4e26\u4e14\u6703\u5f15\u767c\u932f\u8aa4\u3002<\/li>\n<li><strong>RESTRICT<\/strong>: \u8207NO ACTION\u985e\u4f3c\uff0c\u4f46\u5728\u57f7\u884c\u66f4\u65b0\u4e4b\u524d\u6703\u7acb\u5373\u6aa2\u67e5\u7d04\u675f\u689d\u4ef6\u3002<\/li>\n<\/ul>\n<h2 id=\"on-update%e7%9a%84%e4%bd%bf%e7%94%a8%e7%af%84%e4%be%8b-vciCBkbtcm\">ON UPDATE\u7684\u4f7f\u7528\u7bc4\u4f8b<\/h2>\n<p>\u4ee5\u4e0b\u662f\u4e00\u500b\u7c21\u55ae\u7684\u7bc4\u4f8b\uff0c\u5c55\u793a\u5982\u4f55\u5728MySQL\u4e2d\u4f7f\u7528ON UPDATE\u6307\u4ee4\u3002<\/p>\n<pre><code>\nCREATE TABLE departments (\n    id INT AUTO_INCREMENT PRIMARY KEY,\n    name VARCHAR(100) NOT NULL\n);\n\nCREATE TABLE employees (\n    id INT AUTO_INCREMENT PRIMARY KEY,\n    name VARCHAR(100) NOT NULL,\n    department_id INT,\n    FOREIGN KEY (department_id) REFERENCES departments(id)\n    ON UPDATE CASCADE\n);\n<\/code><\/pre>\n<p>\u5728\u9019\u500b\u7bc4\u4f8b\u4e2d\uff0c\u6211\u5011\u5275\u5efa\u4e86\u5169\u500b\u8868\uff1adepartments\u548cemployees\u3002\u7576departments\u8868\u4e2d\u7684id\u88ab\u66f4\u65b0\u6642\uff0cemployees\u8868\u4e2d\u76f8\u61c9\u7684department_id\u4e5f\u6703\u81ea\u52d5\u66f4\u65b0\uff0c\u9019\u6a23\u53ef\u4ee5\u78ba\u4fdd\u8cc7\u6599\u7684\u4e00\u81f4\u6027\u3002<\/p>\n<h2 id=\"on-update%e7%9a%84%e6%87%89%e7%94%a8%e5%a0%b4%e6%99%af-vciCBkbtcm\">ON UPDATE\u7684\u61c9\u7528\u5834\u666f<\/h2>\n<p>ON UPDATE\u6307\u4ee4\u5728\u8a31\u591a\u5834\u666f\u4e2d\u90fd\u975e\u5e38\u6709\u7528\uff0c\u7279\u5225\u662f\u5728\u4ee5\u4e0b\u60c5\u6cc1\u4e0b\uff1a<\/p>\n<ul>\n<li><strong>\u8cc7\u6599\u5eab\u8a2d\u8a08\u4e2d\u7684\u95dc\u806f\u6027\uff1a<\/strong>\u7576\u4e00\u500b\u8868\u7684\u8cc7\u6599\u66f4\u65b0\u6642\uff0c\u53ef\u80fd\u9700\u8981\u66f4\u65b0\u5176\u4ed6\u8868\u4e2d\u7684\u76f8\u95dc\u8cc7\u6599\uff0c\u4ee5\u4fdd\u6301\u8cc7\u6599\u7684\u4e00\u81f4\u6027\u3002<\/li>\n<li><strong>\u591a\u7528\u6236\u74b0\u5883\uff1a<\/strong>\u5728\u591a\u7528\u6236\u74b0\u5883\u4e2d\uff0c\u8cc7\u6599\u7684\u66f4\u65b0\u53ef\u80fd\u6703\u983b\u7e41\u767c\u751f\uff0c\u4f7f\u7528ON UPDATE\u53ef\u4ee5\u81ea\u52d5\u8655\u7406\u9019\u4e9b\u8b8a\u66f4\uff0c\u6e1b\u5c11\u624b\u52d5\u7dad\u8b77\u7684\u5de5\u4f5c\u91cf\u3002<\/li>\n<li><strong>\u6578\u64da\u5b8c\u6574\u6027\uff1a<\/strong>\u4f7f\u7528ON UPDATE\u53ef\u4ee5\u78ba\u4fdd\u8cc7\u6599\u7684\u5b8c\u6574\u6027\uff0c\u907f\u514d\u56e0\u70ba\u624b\u52d5\u66f4\u65b0\u800c\u5c0e\u81f4\u7684\u8cc7\u6599\u4e0d\u4e00\u81f4\u554f\u984c\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b8%bd%e7%b5%90-vciCBkbtcm\">\u7e3d\u7d50<\/h2>\n<p>MySQL\u4e2d\u7684ON UPDATE\u6307\u4ee4\u662f\u4e00\u500b\u5f37\u5927\u7684\u5de5\u5177\uff0c\u53ef\u4ee5\u5e6b\u52a9\u958b\u767c\u8005\u5728\u8cc7\u6599\u66f4\u65b0\u6642\u81ea\u52d5\u8655\u7406\u76f8\u95dc\u8cc7\u6599\u7684\u8b8a\u66f4\u3002\u901a\u904e\u4f7f\u7528ON UPDATE\uff0c\u958b\u767c\u8005\u53ef\u4ee5\u78ba\u4fdd\u8cc7\u6599\u7684\u4e00\u81f4\u6027\u548c\u5b8c\u6574\u6027\uff0c\u7279\u5225\u662f\u5728\u8907\u96dc\u7684\u8cc7\u6599\u5eab\u8a2d\u8a08\u4e2d\u3002\u4e86\u89e3\u5982\u4f55\u6b63\u78ba\u4f7f\u7528\u9019\u4e9b\u6307\u4ee4\uff0c\u5c07\u6709\u52a9\u65bc\u63d0\u5347\u8cc7\u6599\u5eab\u7684\u7ba1\u7406\u6548\u7387\u548c\u53ef\u9760\u6027\u3002<\/p>\n<p>\u5982\u679c\u60a8\u5c0d\u65bc\u8cc7\u6599\u5eab\u7ba1\u7406\u6216\u5176\u4ed6\u76f8\u95dc\u6280\u8853\u6709\u8208\u8da3\uff0c\u6b61\u8fce\u8a2a\u554f\u6211\u5011\u7684\u7db2\u7ad9\u4e86\u89e3\u66f4\u591a\u8cc7\u8a0a\uff0c\u7279\u5225\u662f\u6211\u5011\u63d0\u4f9b\u7684<a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a>\u89e3\u6c7a\u65b9\u6848\uff0c\u5e6b\u52a9\u60a8\u66f4\u597d\u5730\u7ba1\u7406\u60a8\u7684\u4f3a\u670d\u5668\u548c\u8cc7\u6599\u5eab\u9700\u6c42\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4e86\u89e3MySQL\u6307\u4ee4\u4e2d\u7684ON UPDATE\u529f\u80fd\uff0c\u5982\u4f55\u5728\u66f4\u65b0\u6642\u81ea\u52d5\u8abf\u6574\u5916\u9375\u7d04\u675f\uff0c\u78ba\u4fdd\u6578\u64da\u4e00\u81f4\u6027\u8207\u5b8c\u6574\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-79336","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/79336","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=79336"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/79336\/revisions"}],"predecessor-version":[{"id":79337,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/79336\/revisions\/79337"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=79336"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=79336"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=79336"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}