{"id":44282,"date":"2024-12-01T11:38:53","date_gmt":"2024-12-01T03:38:53","guid":{"rendered":"https:\/\/fwq.ai\/blog\/44282\/"},"modified":"2024-12-01T11:38:53","modified_gmt":"2024-12-01T03:38:53","slug":"%e8%87%aa%e5%8a%a8%e5%ae%9e%e7%8e%b0mysql%e5%a4%96%e9%94%ae%e5%92%8c%e4%b8%bb%e9%94%ae%e8%bf%9e%e6%8e%a5%e7%9a%84%e6%96%b9%e6%b3%95%e6%9c%89%e5%93%aa%e4%ba%9b%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/fwq.ai\/blog\/44282\/","title":{"rendered":"\u81ea\u52a8\u5b9e\u73b0MySQL\u5916\u952e\u548c\u4e3b\u952e\u8fde\u63a5\u7684\u65b9\u6cd5\u6709\u54ea\u4e9b\uff1f"},"content":{"rendered":"

<\/b> <\/p>\n

\u81ea\u52a8\u5b9e\u73b0MySQL\u5916\u952e\u548c\u4e3b\u952e\u8fde\u63a5\u7684\u65b9\u6cd5\u6709\u54ea\u4e9b\uff1f<\/h1>\n

\u5728 MySQL \u6570\u636e\u5e93\u4e2d\uff0c\u5916\u952e\u548c\u4e3b\u952e\u662f\u91cd\u8981\u7684\u7ea6\u675f\uff0c\u7528\u4e8e\u786e\u4fdd\u6570\u636e\u5b8c\u6574\u6027\u3002\u4e3a\u4e86\u7b80\u5316\u5916\u952e\u548c\u4e3b\u952e\u7684\u8fde\u63a5\uff0c\u6709\u51e0\u79cd\u81ea\u52a8\u5b9e\u73b0\u65b9\u6cd5\u3002\u672c\u6587\u5c06\u4ecb\u7ecd\u4e09\u79cd\u65b9\u6cd5\uff1a\u4f7f\u7528 ALTER TABLE \u8bed\u53e5\u6dfb\u52a0\u5916\u952e\u7ea6\u675f\u3001\u4f7f\u7528 ON DELETE CASCADE \u8bbe\u7f6e\u7ea7\u8054\u66f4\u65b0\u548c\u5220\u9664\uff0c\u4ee5\u53ca\u4f7f\u7528\u89e6\u53d1\u5668\u5b9e\u73b0\u590d\u6742\u903b\u8f91\u7684\u5916\u952e\u7ea6\u675f\u3002\u8fd9\u4e9b\u65b9\u6cd5\u5c06\u5e2e\u52a9\u5f00\u53d1\u8005\u8f7b\u677e\u5efa\u7acb\u548c\u7ef4\u62a4\u6570\u636e\u5e93\u4e2d\u7684\u6570\u636e\u5173\u8054\uff0c\u4ece\u800c\u63d0\u9ad8\u6570\u636e\u53ef\u9760\u6027\u548c\u6548\u7387\u3002<\/p>\n

\u5b9e\u73b0MySQL\u5916\u952e\u548c\u4e3b\u952e\u81ea\u52a8\u8fde\u63a5\u7684\u65b9\u6cd5\u6709\u54ea\u4e9b\uff1f \u8fd9\u662f\u4e00\u4e2a\u5e38\u89c1\u7684\u95ee\u9898\uff0c\u5f88\u591a\u5f00\u53d1\u8005\u5728\u4f7f\u7528MySQL\u6570\u636e\u5e93\u65f6\u4f1a\u9047\u5230\u8fd9\u4e2a\u9700\u6c42\u3002\u5728MySQL\u4e2d\uff0c\u5916\u952e\u548c\u4e3b\u952e\u662f\u4e24\u4e2a\u91cd\u8981\u7684\u6570\u636e\u5e93\u7ea6\u675f\uff0c\u5b83\u4eec\u53ef\u4ee5\u786e\u4fdd\u6570\u636e\u7684\u5b8c\u6574\u6027\u548c\u4e00\u81f4\u6027\u3002\u5728\u5b9e\u9645\u7684\u6570\u636e\u5e93\u8bbe\u8ba1\u548c\u4f7f\u7528\u4e2d\uff0c\u6211\u4eec\u7ecf\u5e38\u9700\u8981\u5bf9\u5916\u952e\u548c\u4e3b\u952e\u8fdb\u884c\u81ea\u52a8\u8fde\u63a5\uff0c\u4ee5\u786e\u4fdd\u76f8\u5173\u6570\u636e\u7684\u6b63\u786e\u6027\u3002\u4e0b\u9762\u5c06\u4ecb\u7ecd\u51e0\u79cd\u5b9e\u73b0MySQL\u5916\u952e\u548c\u4e3b\u952e\u81ea\u52a8\u8fde\u63a5\u7684\u65b9\u6cd5\uff0c\u5e76\u63d0\u4f9b\u5177\u4f53\u7684\u4ee3\u7801\u793a\u4f8b\u3002<\/p>\n

\u65b9\u6cd5\u4e00\uff1a\u4f7f\u7528ALTER TABLE\u8bed\u53e5\u6dfb\u52a0\u5916\u952e\u7ea6\u675f<\/p>\n

\u901a\u8fc7\u4f7f\u7528ALTER TABLE\u8bed\u53e5\uff0c\u53ef\u4ee5\u4e3a\u5df2\u5b58\u5728\u7684\u8868\u6dfb\u52a0\u5916\u952e\u7ea6\u675f\uff0c\u786e\u4fdd\u5916\u952e\u548c\u4e3b\u952e\u7684\u81ea\u52a8\u8fde\u63a5\u3002\u5177\u4f53\u6b65\u9aa4\u5982\u4e0b\uff1a<\/p>\n

-- \u9996\u5148\u521b\u5efa\u4e24\u4e2a\u8868\uff0c\u5176\u4e2d\u8868A\u5305\u542b\u4e3b\u952e\uff0c\u8868B\u5305\u542b\u5916\u952e\nCREATE TABLE table_A (\n    id INT PRIMARY KEY,\n    name VARCHAR(50)\n);\n\nCREATE TABLE table_B (\n    id INT,\n    a_id INT,\n    FOREIGN KEY (a_id) REFERENCES table_A(id)\n);\n\n-- \u4f7f\u7528ALTER TABLE\u8bed\u53e5\u4e3a\u8868B\u6dfb\u52a0\u5916\u952e\u7ea6\u675f\nALTER TABLE table_B ADD CONSTRAINT fk_a_id FOREIGN KEY (a_id) REFERENCES table_A(id);<\/pre>\n
\u5728\u4e0a\u9762\u7684\u793a\u4f8b\u4e2d\uff0c\u901a\u8fc7ALTER TABLE\u8bed\u53e5\u4e3a\u8868B\u6dfb\u52a0\u4e86\u5bf9\u8868A\u4e2d\u4e3b\u952eid\u7684\u5916\u952e\u7ea6\u675f\u3002\u8fd9\u6837\uff0c\u5f53\u5411\u8868B\u4e2d\u63d2\u5165\u6570\u636e\u65f6\uff0c\u7cfb\u7edf\u4f1a\u81ea\u52a8\u68c0\u67e5\u5e76\u786e\u4fdd\u5916\u952e\u503c\u5728\u8868A\u4e2d\u5b58\u5728\uff0c\u4ece\u800c\u5b9e\u73b0\u4e86\u5916\u952e\u548c\u4e3b\u952e\u7684\u81ea\u52a8\u8fde\u63a5\u3002<\/p>\n
\u65b9\u6cd5\u4e8c\uff1a\u4f7f\u7528ON DELETE CASCADE\u8bbe\u7f6e\u7ea7\u8054\u66f4\u65b0\u548c\u5220\u9664<\/p>\n
\u5728\u6570\u636e\u5e93\u8bbe\u8ba1\u4e2d\uff0c\u6709\u65f6\u5019\u6211\u4eec\u5e0c\u671b\u5f53\u4e3b\u8868\u4e2d\u7684\u8bb0\u5f55\u88ab\u5220\u9664\u65f6\uff0c\u4e0e\u4e4b\u5173\u8054\u7684\u5916\u8868\u8bb0\u5f55\u4e5f\u4f1a\u76f8\u5e94\u88ab\u5220\u9664\u6216\u66f4\u65b0\u3002\u8fd9\u65f6\u53ef\u4ee5\u4f7f\u7528ON DELETE CASCADE\u6765\u8bbe\u7f6e\u7ea7\u8054\u66f4\u65b0\u548c\u5220\u9664\u3002\u4e0b\u9762\u662f\u4e00\u4e2a\u793a\u4f8b\uff1a<\/p>\n
CREATE TABLE table_A (\n    id INT PRIMARY KEY,\n    name VARCHAR(50)\n);\n\nCREATE TABLE table_B (\n    id INT,\n    a_id INT,\n    FOREIGN KEY (a_id) REFERENCES table_A(id) ON DELETE CASCADE\n);<\/pre>\n
\u5728\u4e0a\u9762\u7684\u793a\u4f8b\u4e2d\uff0c\u5f53\u8868A\u4e2d\u7684\u8bb0\u5f55\u88ab\u5220\u9664\u65f6\uff0c\u8868B\u4e2d\u4e0e\u4e4b\u5173\u8054\u7684\u5916\u952e\u8bb0\u5f55\u4e5f\u4f1a\u88ab\u5220\u9664\uff0c\u4ece\u800c\u4fdd\u6301\u5916\u952e\u548c\u4e3b\u952e\u7684\u81ea\u52a8\u8fde\u63a5\u3002<\/p>\n
\u65b9\u6cd5\u4e09\uff1a\u4f7f\u7528\u89e6\u53d1\u5668\u5b9e\u73b0\u590d\u6742\u903b\u8f91\u7684\u5916\u952e\u7ea6\u675f<\/p>\n
\u6709\u65f6\u5019\uff0c\u9700\u8981\u5728\u5916\u952e\u7ea6\u675f\u4e0a\u5b9e\u73b0\u4e00\u4e9b\u590d\u6742\u7684\u903b\u8f91\uff0c\u6bd4\u5982\u68c0\u67e5\u6570\u636e\u7684\u6709\u6548\u6027\u6216\u6267\u884c\u7279\u5b9a\u7684\u64cd\u4f5c\u3002\u8fd9\u65f6\u53ef\u4ee5\u4f7f\u7528\u89e6\u53d1\u5668\u6765\u5b9e\u73b0\u3002\u4e0b\u9762\u662f\u4e00\u4e2a\u793a\u4f8b\uff1a<\/p>\n
CREATE TRIGGER check_fk BEFORE INSERT ON table_B\nFOR EACH ROW\nBEGIN\n    IF NOT EXISTS (SELECT 1 FROM table_A WHERE id = NEW.a_id) THEN\n        SIGNAL SQLSTATE '45000'\n        SET MESSAGE_TEXT = 'Invalid foreign key value';\n    END IF;\nEND;<\/pre>\n
\u5728\u4e0a\u9762\u7684\u793a\u4f8b\u4e2d\uff0c\u521b\u5efa\u4e86\u4e00\u4e2aBEFORE INSERT\u7684\u89e6\u53d1\u5668\uff0c\u7528\u4e8e\u5728\u63d2\u5165\u6570\u636e\u5230\u8868B\u524d\u68c0\u67e5\u5916\u952e\u503c\u7684\u6709\u6548\u6027\u3002\u5982\u679c\u5916\u952e\u503c\u4e0d\u5b58\u5728\u4e8e\u8868A\u4e2d\uff0c\u5219\u4f1a\u89e6\u53d1\u4e00\u4e2a\u5f02\u5e38\u3002\u901a\u8fc7\u8fd9\u79cd\u65b9\u5f0f\u53ef\u4ee5\u5b9e\u73b0\u66f4\u590d\u6742\u7684\u5916\u952e\u7ea6\u675f\u903b\u8f91\u3002<\/p>\n
\u7efc\u4e0a\u6240\u8ff0\uff0c\u901a\u8fc7ALTER TABLE\u8bed\u53e5\u3001ON DELETE CASCADE\u548c\u89e6\u53d1\u5668\u7b49\u65b9\u6cd5\uff0c\u53ef\u4ee5\u5b9e\u73b0MySQL\u5916\u952e\u548c\u4e3b\u952e\u7684\u81ea\u52a8\u8fde\u63a5\u3002\u5f00\u53d1\u8005\u53ef\u4ee5\u6839\u636e\u5177\u4f53\u9700\u6c42\u9009\u62e9\u5408\u9002\u7684\u65b9\u6cd5\u6765\u786e\u4fdd\u6570\u636e\u7684\u4e00\u81f4\u6027\u548c\u5b8c\u6574\u6027\u3002<\/p>\n
\u7ec8\u4e8e\u4ecb\u7ecd\u5b8c\u5566\uff01\u5c0f\u4f19\u4f34\u4eec\uff0c\u8fd9\u7bc7\u5173\u4e8e\u300a\u81ea\u52a8\u5b9e\u73b0MySQL\u5916\u952e\u548c\u4e3b\u952e\u8fde\u63a5\u7684\u65b9\u6cd5\u6709\u54ea\u4e9b\uff1f\u300b\u7684\u4ecb\u7ecd\u5e94\u8be5\u8ba9\u4f60\u6536\u83b7\u591a\u591a\u4e86\u5427\uff01\u6b22\u8fce\u5927\u5bb6\u6536\u85cf\u6216\u5206\u4eab\u7ed9\u66f4\u591a\u9700\u8981\u5b66\u4e60\u7684\u670b\u53cb\u5427~\u7c73\u4e91\u516c\u4f17\u53f7\u4e5f\u4f1a\u53d1\u5e03\u6570\u636e\u5e93\u76f8\u5173\u77e5\u8bc6\uff0c\u5feb\u6765\u5173\u6ce8\u5427\uff01<\/p>\n
\n
\n <\/dt>\n<\/dl>\n","protected":false},"excerpt":{"rendered":"
\u81ea\u52a8\u5b9e\u73b0MySQL\u5916\u952e\u548c\u4e3b\u952e\u8fde\u63a5\u7684\u65b9\u6cd5\u6709\u54ea\u4e9b\uff1f \u5728 MySQL \u6570\u636e\u5e93\u4e2d\uff0c\u5916\u952e\u548c\u4e3b\u952e\u662f\u91cd\u8981\u7684\u7ea6\u675f\uff0c\u7528\u4e8e\u786e\u4fdd\u6570\u636e\u5b8c\u6574\u6027\u3002\u4e3a\u4e86\u7b80\u5316\u5916\u952e\u548c\u4e3b\u952e\u7684\u8fde\u63a5\uff0c\u6709\u51e0\u79cd\u81ea\u52a8\u5b9e\u73b0\u65b9\u6cd5\u3002\u672c\u6587\u5c06\u4ecb\u7ecd\u4e09\u79cd\u65b9\u6cd5\uff1a\u4f7f\u7528 ALTER TABLE \u8bed\u53e5\u6dfb\u52a0\u5916\u952e\u7ea6\u675f\u3001\u4f7f\u7528 ON DELETE CASCADE \u8bbe\u7f6e\u7ea7\u8054\u66f4\u65b0\u548c\u5220\u9664\uff0c\u4ee5\u53ca\u4f7f\u7528\u89e6\u53d1\u5668\u5b9e\u73b0\u590d\u6742\u903b\u8f91\u7684\u5916\u952e\u7ea6\u675f\u3002\u8fd9\u4e9b\u65b9\u6cd5\u5c06\u5e2e\u52a9\u5f00\u53d1\u8005\u8f7b\u677e\u5efa\u7acb\u548c\u7ef4\u62a4\u6570\u636e\u5e93\u4e2d\u7684\u6570\u636e\u5173\u8054\uff0c\u4ece\u800c\u63d0\u9ad8\u6570\u636e\u53ef\u9760\u6027\u548c\u6548\u7387\u3002 \u5b9e\u73b0MySQL\u5916\u952e\u548c\u4e3b\u952e\u81ea\u52a8\u8fde\u63a5\u7684\u65b9\u6cd5\u6709\u54ea\u4e9b\uff1f \u8fd9\u662f\u4e00\u4e2a\u5e38\u89c1\u7684\u95ee\u9898\uff0c\u5f88\u591a\u5f00\u53d1\u8005\u5728\u4f7f\u7528MySQL\u6570\u636e\u5e93\u65f6\u4f1a\u9047\u5230\u8fd9\u4e2a\u9700\u6c42\u3002\u5728MySQL\u4e2d\uff0c\u5916\u952e\u548c\u4e3b\u952e\u662f\u4e24\u4e2a\u91cd\u8981\u7684\u6570\u636e\u5e93\u7ea6\u675f\uff0c\u5b83\u4eec\u53ef\u4ee5\u786e\u4fdd\u6570\u636e\u7684\u5b8c\u6574\u6027\u548c\u4e00\u81f4\u6027\u3002\u5728\u5b9e\u9645\u7684\u6570\u636e\u5e93\u8bbe\u8ba1\u548c\u4f7f\u7528\u4e2d\uff0c\u6211\u4eec\u7ecf\u5e38\u9700\u8981\u5bf9\u5916\u952e\u548c\u4e3b\u952e\u8fdb\u884c\u81ea\u52a8\u8fde\u63a5\uff0c\u4ee5\u786e\u4fdd\u76f8\u5173\u6570\u636e\u7684\u6b63\u786e\u6027\u3002\u4e0b\u9762\u5c06\u4ecb\u7ecd\u51e0\u79cd\u5b9e\u73b0MySQL\u5916\u952e\u548c\u4e3b\u952e\u81ea\u52a8\u8fde\u63a5\u7684\u65b9\u6cd5\uff0c\u5e76\u63d0\u4f9b\u5177\u4f53\u7684\u4ee3\u7801\u793a\u4f8b\u3002 \u65b9\u6cd5\u4e00\uff1a\u4f7f\u7528ALTER TABLE\u8bed\u53e5\u6dfb\u52a0\u5916\u952e\u7ea6\u675f \u901a\u8fc7\u4f7f\u7528ALTER TABLE\u8bed\u53e5\uff0c\u53ef\u4ee5\u4e3a\u5df2\u5b58\u5728\u7684\u8868\u6dfb\u52a0\u5916\u952e\u7ea6\u675f\uff0c\u786e\u4fdd\u5916\u952e\u548c\u4e3b\u952e\u7684\u81ea\u52a8\u8fde\u63a5\u3002\u5177\u4f53\u6b65\u9aa4\u5982\u4e0b\uff1a — \u9996\u5148\u521b\u5efa\u4e24\u4e2a\u8868\uff0c\u5176\u4e2d\u8868A\u5305\u542b\u4e3b\u952e\uff0c\u8868B\u5305\u542b\u5916\u952e CREATE TABLE table_A ( id INT PRIMARY KEY, name VARCHAR(50) ); CREATE TABLE table_B ( id INT, a_id INT, FOREIGN KEY (a_id) REFERENCES table_A(id) ); — \u4f7f\u7528ALTER TABLE\u8bed\u53e5\u4e3a\u8868B\u6dfb\u52a0\u5916\u952e\u7ea6\u675f ALTER TABLE table_B ADD CONSTRAINT fk_a_id FOREIGN KEY […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[16],"tags":[],"class_list":["post-44282","post","type-post","status-publish","format-standard","hentry","category-16"],"_links":{"self":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/44282","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/comments?post=44282"}],"version-history":[{"count":0,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/44282\/revisions"}],"wp:attachment":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/media?parent=44282"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/categories?post=44282"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/tags?post=44282"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}