{"id":77916,"date":"2024-10-16T11:18:16","date_gmt":"2024-10-16T03:18:16","guid":{"rendered":"https:\/\/server.hk\/cnblog\/77916\/"},"modified":"2024-10-16T11:18:16","modified_gmt":"2024-10-16T03:18:16","slug":"mysql%e6%8c%87%e4%bb%a4-check%ef%bc%88%e6%aa%a2%e6%9f%a5%ef%bc%89","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/77916\/","title":{"rendered":"MySQL\u6307\u4ee4: CHECK\uff08\u6aa2\u67e5\uff09"},"content":{"rendered":"

MySQL\u6307\u4ee4: CHECK\uff08\u6aa2\u67e5\uff09<\/h1>\n

\u5728\u8cc7\u6599\u5eab\u7ba1\u7406\u4e2d\uff0cMySQL\u662f\u4e00\u500b\u5ee3\u6cdb\u4f7f\u7528\u7684\u95dc\u806f\u5f0f\u8cc7\u6599\u5eab\u7ba1\u7406\u7cfb\u7d71\u3002\u5b83\u63d0\u4f9b\u4e86\u591a\u7a2e\u6307\u4ee4\u4f86\u5e6b\u52a9\u7528\u6236\u7ba1\u7406\u548c\u7dad\u8b77\u8cc7\u6599\u5eab\uff0c\u5176\u4e2d\u4e4b\u4e00\u5c31\u662fCHECK\u6307\u4ee4\u3002\u9019\u7bc7\u6587\u7ae0\u5c07\u6df1\u5165\u63a2\u8a0eMySQL\u4e2d\u7684CHECK\u6307\u4ee4\uff0c\u5305\u62ec\u5176\u7528\u9014\u3001\u8a9e\u6cd5\u53ca\u5be6\u969b\u7bc4\u4f8b\u3002<\/p>\n

CHECK\u6307\u4ee4\u7684\u7528\u9014<\/h2>\n

CHECK\u6307\u4ee4\u4e3b\u8981\u7528\u65bc\u6aa2\u67e5\u8cc7\u6599\u8868\u4e2d\u7684\u8cc7\u6599\u5b8c\u6574\u6027\u3002\u5b83\u53ef\u4ee5\u78ba\u4fdd\u8cc7\u6599\u7b26\u5408\u7279\u5b9a\u7684\u689d\u4ef6\uff0c\u5f9e\u800c\u9632\u6b62\u4e0d\u6b63\u78ba\u6216\u4e0d\u4e00\u81f4\u7684\u8cc7\u6599\u9032\u5165\u8cc7\u6599\u5eab\u3002\u9019\u5c0d\u65bc\u7dad\u8b77\u8cc7\u6599\u7684\u6e96\u78ba\u6027\u548c\u53ef\u9760\u6027\u81f3\u95dc\u91cd\u8981\u3002<\/p>\n

CHECK\u7d04\u675f\u7684\u8a9e\u6cd5<\/h2>\n

\u5728MySQL\u4e2d\uff0cCHECK\u7d04\u675f\u901a\u5e38\u5728\u5275\u5efa\u6216\u4fee\u6539\u8cc7\u6599\u8868\u6642\u4f7f\u7528\u3002\u5176\u57fa\u672c\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n

CREATE TABLE table_name (\n    column_name data_type CHECK (condition)\n);<\/code><\/pre>\n
\u6216\u8005\u5728\u4fee\u6539\u73fe\u6709\u8cc7\u6599\u8868\u6642\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u8a9e\u6cd5\uff1a<\/p>\n
ALTER TABLE table_name\nADD CONSTRAINT constraint_name CHECK (condition);<\/code><\/pre>\n
CHECK\u7d04\u675f\u7684\u7bc4\u4f8b<\/h2>\n
\u4ee5\u4e0b\u662f\u4e00\u500b\u4f7f\u7528CHECK\u7d04\u675f\u7684\u7bc4\u4f8b\uff0c\u5047\u8a2d\u6211\u5011\u8981\u5275\u5efa\u4e00\u500b\u7528\u65bc\u5b58\u5132\u54e1\u5de5\u8cc7\u6599\u7684\u8cc7\u6599\u8868\uff0c\u4e26\u78ba\u4fdd\u54e1\u5de5\u7684\u5e74\u9f61\u5fc5\u9808\u5927\u65bc18\u6b72\uff1a<\/p>\n
CREATE TABLE Employees (\n    ID INT PRIMARY KEY,\n    Name VARCHAR(100),\n    Age INT CHECK (Age > 18)\n);<\/code><\/pre>\n
\u5728\u9019\u500b\u7bc4\u4f8b\u4e2d\uff0c\u7576\u6211\u5011\u5617\u8a66\u63d2\u5165\u4e00\u500b\u5e74\u9f61\u5c0f\u65bc\u6216\u7b49\u65bc18\u7684\u54e1\u5de5\u8cc7\u6599\u6642\uff0cMySQL\u5c07\u6703\u62d2\u7d55\u9019\u500b\u64cd\u4f5c\uff0c\u5f9e\u800c\u4fdd\u8b77\u8cc7\u6599\u7684\u5b8c\u6574\u6027\u3002<\/p>\n
\u6aa2\u67e5\u73fe\u6709\u8cc7\u6599\u8868\u7684CHECK\u7d04\u675f<\/h2>\n
\u5982\u679c\u60a8\u5df2\u7d93\u6709\u4e00\u500b\u8cc7\u6599\u8868\u4e26\u5e0c\u671b\u6dfb\u52a0CHECK\u7d04\u675f\uff0c\u53ef\u4ee5\u4f7f\u7528ALTER TABLE\u6307\u4ee4\u3002\u4f8b\u5982\uff0c\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u540d\u70baProducts\u7684\u8cc7\u6599\u8868\uff0c\u4e26\u5e0c\u671b\u78ba\u4fdd\u7522\u54c1\u7684\u50f9\u683c\u5fc5\u9808\u5927\u65bc\u96f6\uff1a<\/p>\n
ALTER TABLE Products\nADD CONSTRAINT price_check CHECK (Price > 0);<\/code><\/pre>\n
\u9019\u6a23\u4e00\u4f86\uff0c\u4efb\u4f55\u8a66\u5716\u63d2\u5165\u50f9\u683c\u5c0f\u65bc\u6216\u7b49\u65bc\u96f6\u7684\u7522\u54c1\u8cc7\u6599\u7684\u64cd\u4f5c\u90fd\u5c07\u88ab\u62d2\u7d55\u3002<\/p>\n
\u6ce8\u610f\u4e8b\u9805<\/h2>\n
\u96d6\u7136CHECK\u7d04\u675f\u5728MySQL\u4e2d\u662f\u975e\u5e38\u6709\u7528\u7684\uff0c\u4f46\u9700\u8981\u6ce8\u610f\u7684\u662f\uff0c\u67d0\u4e9b\u7248\u672c\u7684MySQL\u53ef\u80fd\u4e0d\u5b8c\u5168\u652f\u6301CHECK\u7d04\u675f\u3002\u56e0\u6b64\uff0c\u5728\u4f7f\u7528\u4e4b\u524d\uff0c\u5efa\u8b70\u6aa2\u67e5\u60a8\u7684MySQL\u7248\u672c\u662f\u5426\u652f\u6301\u6b64\u529f\u80fd\u3002\u6b64\u5916\uff0cCHECK\u7d04\u675f\u7684\u6027\u80fd\u5f71\u97ff\u901a\u5e38\u662f\u5fae\u4e4e\u5176\u5fae\u7684\uff0c\u4f46\u5728\u8655\u7406\u5927\u91cf\u8cc7\u6599\u6642\uff0c\u4ecd\u9700\u8b39\u614e\u8003\u616e\u3002<\/p>\n
\u7e3d\u7d50<\/h2>\n
CHECK\u6307\u4ee4\u5728MySQL\u4e2d\u662f\u4e00\u500b\u91cd\u8981\u7684\u5de5\u5177\uff0c\u7528\u65bc\u78ba\u4fdd\u8cc7\u6599\u7684\u5b8c\u6574\u6027\u548c\u4e00\u81f4\u6027\u3002\u901a\u904e\u4f7f\u7528CHECK\u7d04\u675f\uff0c\u958b\u767c\u8005\u53ef\u4ee5\u6709\u6548\u5730\u9632\u6b62\u4e0d\u6b63\u78ba\u7684\u8cc7\u6599\u9032\u5165\u8cc7\u6599\u5eab\uff0c\u5f9e\u800c\u63d0\u9ad8\u8cc7\u6599\u7684\u53ef\u9760\u6027\u3002\u5c0d\u65bc\u9700\u8981\u9ad8\u6548\u80fd\u548c\u7a69\u5b9a\u6027\u7684\u61c9\u7528\uff0c\u9078\u64c7\u5408\u9069\u7684\u8cc7\u6599\u5eab\u89e3\u6c7a\u65b9\u6848\u81f3\u95dc\u91cd\u8981\u3002\u5982\u679c\u60a8\u6b63\u5728\u5c0b\u627e\u9ad8\u6548\u7684 \u9999\u6e2fVPS<\/a> \u670d\u52d9\uff0cServer.HK\u63d0\u4f9b\u591a\u7a2e\u9078\u64c7\u4ee5\u6eff\u8db3\u60a8\u7684\u9700\u6c42\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
\u4e86\u89e3MySQL\u6307\u4ee4CHECK\u7684\u7528\u6cd5\uff0c\u5982\u4f55\u5728\u8cc7\u6599\u8868\u4e2d\u8a2d\u7f6e\u7d04\u675f\u689d\u4ef6\u4ee5\u78ba\u4fdd\u6578\u64da\u7684\u5b8c\u6574\u6027\u548c\u6b63\u78ba\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-77916","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/77916","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=77916"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/77916\/revisions"}],"predecessor-version":[{"id":77917,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/77916\/revisions\/77917"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=77916"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=77916"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=77916"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}