{"id":151567,"date":"2024-11-01T17:41:23","date_gmt":"2024-11-01T09:41:23","guid":{"rendered":"https:\/\/server.hk\/cnblog\/151567\/"},"modified":"2024-11-01T17:41:24","modified_gmt":"2024-11-01T09:41:24","slug":"%e6%93%ba%e8%84%ab%e9%ba%bb%e7%85%a9%ef%bc%8c%e6%95%b8%e6%93%9a%e5%ba%ab%e4%b8%8d%e7%94%a8%e5%a4%96%e9%8d%b5%e7%9a%84%e5%a6%99%e6%8b%9b-%e6%95%b8%e6%93%9a%e5%ba%ab%e4%b8%8d%e7%94%a8%e5%a4%96%e9%8d%b5","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/151567\/","title":{"rendered":"\u64fa\u812b\u9ebb\u7169\uff0c\u6578\u64da\u5eab\u4e0d\u7528\u5916\u9375\u7684\u5999\u62db (\u6578\u64da\u5eab\u4e0d\u7528\u5916\u9375)"},"content":{"rendered":"<h1 id=\"%e6%93%ba%e8%84%ab%e9%ba%bb%e7%85%a9%ef%bc%8c%e6%95%b8%e6%93%9a%e5%ba%ab%e4%b8%8d%e7%94%a8%e5%a4%96%e9%8d%b5%e7%9a%84%e5%a6%99%e6%8b%9b-ufqazxgSyc\">\u64fa\u812b\u9ebb\u7169\uff0c\u6578\u64da\u5eab\u4e0d\u7528\u5916\u9375\u7684\u5999\u62db<\/h1>\n<p>\u5728\u6578\u64da\u5eab\u8a2d\u8a08\u4e2d\uff0c\u5916\u9375\uff08Foreign 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id=\"%e5%a4%96%e9%8d%b5%e7%9a%84%e6%8c%91%e6%88%b0-ufqazxgSyc\">\u5916\u9375\u7684\u6311\u6230<\/h2>\n<p>\u5916\u9375\u7684\u4e3b\u8981\u529f\u80fd\u662f\u78ba\u4fdd\u6578\u64da\u4e4b\u9593\u7684\u95dc\u806f\u6027\uff0c\u9632\u6b62\u5b64\u7acb\u7684\u6578\u64da\u51fa\u73fe\u3002\u7136\u800c\uff0c\u9019\u4e5f\u53ef\u80fd\u5c0e\u81f4\u4ee5\u4e0b\u5e7e\u500b\u554f\u984c\uff1a<\/p>\n<ul>\n<li><strong>\u6027\u80fd\u554f\u984c\uff1a<\/strong>\u5728\u5927\u578b\u6578\u64da\u5eab\u4e2d\uff0c\u5916\u9375\u7d04\u675f\u53ef\u80fd\u6703\u5f71\u97ff\u67e5\u8a62\u6027\u80fd\uff0c\u7279\u5225\u662f\u5728\u9032\u884c\u5927\u91cf\u63d2\u5165\u6216\u66f4\u65b0\u64cd\u4f5c\u6642\u3002<\/li>\n<li><strong>\u6578\u64da\u9077\u79fb\u56f0\u96e3\uff1a<\/strong>\u7576\u9700\u8981\u91cd\u69cb\u6578\u64da\u5eab\u7d50\u69cb\u6216\u9032\u884c\u6578\u64da\u9077\u79fb\u6642\uff0c\u5916\u9375\u7d04\u675f\u53ef\u80fd\u6703\u589e\u52a0\u8907\u96dc\u6027\uff0c\u5c0e\u81f4\u9077\u79fb\u904e\u7a0b\u4e2d\u7684\u932f\u8aa4\u3002<\/li>\n<li><strong>\u7dad\u8b77\u6311\u6230\uff1a<\/strong>\u96a8\u8457\u6578\u64da\u5eab\u7684\u589e\u9577\uff0c\u7dad\u8b77\u5916\u9375\u7d04\u675f\u53ef\u80fd\u6703\u8b8a\u5f97\u66f4\u52a0\u56f0\u96e3\uff0c\u7279\u5225\u662f\u5728\u591a\u500b\u8868\u4e4b\u9593\u5b58\u5728\u8907\u96dc\u95dc\u806f\u7684\u60c5\u6cc1\u4e0b\u3002<\/li>\n<\/ul>\n<h2 id=\"%e4%b8%8d%e4%bd%bf%e7%94%a8%e5%a4%96%e9%8d%b5%e7%9a%84%e6%9b%bf%e4%bb%a3%e6%96%b9%e6%a1%88-ufqazxgSyc\">\u4e0d\u4f7f\u7528\u5916\u9375\u7684\u66ff\u4ee3\u65b9\u6848<\/h2>\n<p>\u5118\u7ba1\u5916\u9375\u5728\u6578\u64da\u5b8c\u6574\u6027\u65b9\u9762\u63d0\u4f9b\u4e86\u4fdd\u969c\uff0c\u4f46\u6211\u5011\u53ef\u4ee5\u901a\u904e\u5176\u4ed6\u65b9\u6cd5\u4f86\u5be6\u73fe\u985e\u4f3c\u7684\u6548\u679c\u3002\u4ee5\u4e0b\u662f\u4e00\u4e9b\u4e0d\u4f7f\u7528\u5916\u9375\u7684\u6280\u5de7\uff1a<\/p>\n<h3 id=\"1-%e6%87%89%e7%94%a8%e7%a8%8b%e5%ba%8f%e5%b1%a4%e9%9d%a2%e7%9a%84%e6%95%b8%e6%93%9a%e9%a9%97%e8%ad%89-ufqazxgSyc\">1. \u61c9\u7528\u7a0b\u5e8f\u5c64\u9762\u7684\u6578\u64da\u9a57\u8b49<\/h3>\n<p>\u5728\u61c9\u7528\u7a0b\u5e8f\u5c64\u9762\u9032\u884c\u6578\u64da\u9a57\u8b49\u662f\u4e00\u7a2e\u6709\u6548\u7684\u66ff\u4ee3\u65b9\u6848\u3002\u901a\u904e\u5728\u6578\u64da\u63d2\u5165\u6216\u66f4\u65b0\u4e4b\u524d\uff0c\u6aa2\u67e5\u76f8\u95dc\u6578\u64da\u7684\u5b58\u5728\u6027\uff0c\u53ef\u4ee5\u78ba\u4fdd\u6578\u64da\u7684\u4e00\u81f4\u6027\u3002\u4f8b\u5982\uff1a<\/p>\n<pre><code>if (checkIfUserExists($userId)) {\n    \/\/ \u63d2\u5165\u6216\u66f4\u65b0\u64cd\u4f5c\n} else {\n    \/\/ \u932f\u8aa4\u8655\u7406\n}<\/code><\/pre>\n<h3 id=\"2-%e4%bd%bf%e7%94%a8%e8%a7%b8%e7%99%bc%e5%99%a8%ef%bc%88triggers%ef%bc%89-ufqazxgSyc\">2. \u4f7f\u7528\u89f8\u767c\u5668\uff08Triggers\uff09<\/h3>\n<p>\u89f8\u767c\u5668\u662f\u4e00\u7a2e\u5728\u7279\u5b9a\u4e8b\u4ef6\u767c\u751f\u6642\u81ea\u52d5\u57f7\u884c\u7684\u7a0b\u5e8f\u3002\u53ef\u4ee5\u5229\u7528\u89f8\u767c\u5668\u4f86\u6aa2\u67e5\u6578\u64da\u7684\u5b8c\u6574\u6027\u3002\u4f8b\u5982\uff0c\u5728\u63d2\u5165\u6216\u66f4\u65b0\u64cd\u4f5c\u4e4b\u524d\uff0c\u89f8\u767c\u5668\u53ef\u4ee5\u6aa2\u67e5\u76f8\u95dc\u8868\u4e2d\u7684\u6578\u64da\u662f\u5426\u5b58\u5728\uff1a<\/p>\n<pre><code>CREATE TRIGGER check_user_exists\nBEFORE INSERT ON orders\nFOR EACH ROW\nBEGIN\n    DECLARE user_count INT;\n    SELECT COUNT(*) INTO user_count FROM users WHERE id = NEW.user_id;\n    IF user_count = 0 THEN\n        SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = 'User does not exist';\n    END IF;\nEND;<\/code><\/pre>\n<h3 id=\"3-%e4%bd%bf%e7%94%a8%e5%94%af%e4%b8%80%e7%b4%a2%e5%bc%95%ef%bc%88unique-indexes%ef%bc%89-ufqazxgSyc\">3. \u4f7f\u7528\u552f\u4e00\u7d22\u5f15\uff08Unique Indexes\uff09<\/h3>\n<p>\u96d6\u7136\u552f\u4e00\u7d22\u5f15\u4e26\u4e0d\u5b8c\u5168\u7b49\u540c\u65bc\u5916\u9375\uff0c\u4f46\u5b83\u53ef\u4ee5\u5e6b\u52a9\u78ba\u4fdd\u67d0\u4e9b\u5217\u7684\u552f\u4e00\u6027\uff0c\u5f9e\u800c\u6e1b\u5c11\u6578\u64da\u4e0d\u4e00\u81f4\u7684\u98a8\u96aa\u3002\u4f8b\u5982\uff1a<\/p>\n<pre><code>CREATE UNIQUE INDEX idx_user_email ON users(email);<\/code><\/pre>\n<h3 id=\"4-%e5%ae%9a%e6%9c%9f%e6%95%b8%e6%93%9a%e6%b8%85%e7%90%86-ufqazxgSyc\">4. \u5b9a\u671f\u6578\u64da\u6e05\u7406<\/h3>\n<p>\u5b9a\u671f\u6aa2\u67e5\u548c\u6e05\u7406\u6578\u64da\u5eab\u4e2d\u7684\u5b64\u7acb\u6578\u64da\uff0c\u53ef\u4ee5\u6709\u6548\u6e1b\u5c11\u6578\u64da\u4e0d\u4e00\u81f4\u7684\u60c5\u6cc1\u3002\u9019\u53ef\u4ee5\u901a\u904e\u5b9a\u671f\u904b\u884c\u67e5\u8a62\u4f86\u5be6\u73fe\uff0c\u4f8b\u5982\uff1a<\/p>\n<pre><code>SELECT * FROM orders WHERE user_id NOT IN (SELECT id FROM users);<\/code><\/pre>\n<h2 id=\"%e7%b5%90%e8%ab%96-ufqazxgSyc\">\u7d50\u8ad6<\/h2>\n<p>\u96d6\u7136\u5916\u9375\u5728\u6578\u64da\u5eab\u8a2d\u8a08\u4e2d\u6709\u5176\u91cd\u8981\u6027\uff0c\u4f46\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\uff0c\u9078\u64c7\u4e0d\u4f7f\u7528\u5916\u9375\u4e5f\u53ef\u4ee5\u9054\u5230\u6578\u64da\u5b8c\u6574\u6027\u7684\u76ee\u7684\u3002\u901a\u904e\u61c9\u7528\u7a0b\u5e8f\u5c64\u9762\u7684\u9a57\u8b49\u3001\u89f8\u767c\u5668\u3001\u552f\u4e00\u7d22\u5f15\u548c\u5b9a\u671f\u6578\u64da\u6e05\u7406\u7b49\u65b9\u6cd5\uff0c\u6211\u5011\u53ef\u4ee5\u6709\u6548\u5730\u7ba1\u7406\u6578\u64da\u95dc\u806f\u6027\uff0c\u6e1b\u5c11\u56e0\u5916\u9375\u5e36\u4f86\u7684\u9ebb\u7169\u3002<\/p>\n<p>\u5982\u679c\u60a8\u6b63\u5728\u5c0b\u627e\u9ad8\u6548\u7684\u6578\u64da\u5eab\u89e3\u6c7a\u65b9\u6848\uff0c\u8003\u616e\u4f7f\u7528<a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a>\u6216<a href=\"https:\/\/server.hk\">\u9999\u6e2f\u4f3a\u670d\u5668<\/a>\u4f86\u652f\u6301\u60a8\u7684\u61c9\u7528\u7a0b\u5e8f\uff0c\u9019\u5c07\u6709\u52a9\u65bc\u63d0\u5347\u6027\u80fd\u548c\u53ef\u9760\u6027\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u63a2\u7d22\u64fa\u812b\u9ebb\u7169\u7684\u6578\u64da\u5eab\u8a2d\u8a08\u6280\u5de7\uff0c\u5b78\u7fd2\u5982\u4f55\u5728\u4e0d\u4f7f\u7528\u5916\u9375\u7684\u60c5\u6cc1\u4e0b\u6709\u6548\u7ba1\u7406\u6578\u64da\u95dc\u806f\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-151567","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/151567","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=151567"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/151567\/revisions"}],"predecessor-version":[{"id":151568,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/151567\/revisions\/151568"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=151567"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=151567"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=151567"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}