{"id":94098,"date":"2026-08-13T18:48:51","date_gmt":"2026-08-13T10:48:51","guid":{"rendered":"https:\/\/www.wsisp.com\/helps\/94098.html"},"modified":"2026-08-13T18:48:51","modified_gmt":"2026-08-13T10:48:51","slug":"%e4%bb%8e%e7%90%86%e8%ae%ba%e5%88%b0%e8%90%bd%e5%9c%b0%ef%bc%9a%e6%95%b0%e6%8d%ae%e5%ba%93%e8%8c%83%e5%bc%8f%ef%bc%881nf-4nf%ef%bc%89%e7%9a%84%e5%87%86%e7%a1%ae%e5%ae%9a%e4%b9%89%e4%b8%8e%e5%b7%a5","status":"publish","type":"post","link":"https:\/\/www.wsisp.com\/helps\/94098.html","title":{"rendered":"\u4ece\u7406\u8bba\u5230\u843d\u5730\uff1a\u6570\u636e\u5e93\u8303\u5f0f\uff081NF-4NF\uff09\u7684\u51c6\u786e\u5b9a\u4e49\u4e0e\u5de5\u7a0b\u53d6\u820d"},"content":{"rendered":"<h3>\u76ee\u5f55<\/h3>\n<ul>\n<li>1. \u4e3a\u4ec0\u4e48\u8fd8\u8981\u8c08\u8303\u5f0f<\/li>\n<li>2. \u5fc5\u5907\u57fa\u7840&#xff1a;\u51fd\u6570\u4f9d\u8d56\u4e0e\u952e<\/li>\n<li>3. \u7b2c\u4e00\u8303\u5f0f&#xff08;1NF&#xff09;&#xff1a;\u539f\u5b50\u6027<\/li>\n<li>4. \u7b2c\u4e8c\u8303\u5f0f&#xff08;2NF&#xff09;&#xff1a;\u6d88\u9664\u90e8\u5206\u51fd\u6570\u4f9d\u8d56<\/li>\n<li>5. \u7b2c\u4e09\u8303\u5f0f&#xff08;3NF&#xff09;&#xff1a;\u6d88\u9664\u4f20\u9012\u51fd\u6570\u4f9d\u8d56<\/li>\n<li>6. BC \u8303\u5f0f&#xff08;BCNF&#xff09;&#xff1a;\u6bd4 3NF \u66f4\u4e25\u683c\u7684\u4e00\u6b65<\/li>\n<li>7. \u7b2c\u56db\u8303\u5f0f&#xff08;4NF&#xff09;&#xff1a;\u76f4\u9762\u591a\u503c\u4f9d\u8d56<\/li>\n<li>8. \u5de5\u7a0b\u53d6\u820d&#xff1a;\u8303\u5f0f\u4e0d\u662f\u6559\u6761\n<ul>\n<li>8.1 \u89c4\u8303\u5316\u4e0d\u662f\u514d\u8d39\u7684<\/li>\n<li>8.2 \u5e38\u89c1\u7684\u843d\u5730\u59ff\u6001<\/li>\n<li>8.3 \u5bf9 1NF \u7684\u91cd\u65b0\u5ba1\u89c6<\/li>\n<\/ul>\n<\/li>\n<li>9. \u843d\u5730\u5efa\u8bae&#xff1a;\u4e00\u4e2a\u53ef\u64cd\u4f5c\u7684\u5224\u65ad\u8def\u5f84<\/li>\n<li>10. \u603b\u7ed3<\/li>\n<\/ul>\n<h3>1. \u4e3a\u4ec0\u4e48\u8fd8\u8981\u8c08\u8303\u5f0f<\/h3>\n<p>\u8303\u5f0f&#xff08;Normal Form&#xff09;\u51e0\u4e4e\u662f\u6bcf\u4e2a\u540e\u7aef\u5f00\u53d1\u8005\u5728\u5165\u95e8\u65f6\u90fd\u4f1a\u63a5\u89e6\u5230\u3001\u5374\u5f88\u5c11\u771f\u6b63\u5403\u900f\u7684\u8bdd\u9898\u3002\u9762\u8bd5\u65f6\u80cc\u5f97\u51fa\u300c3NF \u5c31\u662f\u6d88\u9664\u4f20\u9012\u4f9d\u8d56\u300d&#xff0c;\u4e00\u5230\u771f\u5b9e\u5efa\u8868&#xff0c;\u5374\u5e38\u5e38\u5728\u300c\u62c6\u4e09\u5f20\u8868\u8fd8\u662f\u5408\u6210\u4e00\u5f20\u5bbd\u8868\u300d\u4e4b\u95f4\u53cd\u590d\u6447\u6446\u3002<\/p>\n<p>\u8303\u5f0f\u7406\u8bba\u7684\u4ef7\u503c\u4e0d\u5728\u70ab\u6280&#xff0c;\u800c\u5728\u4e8e\u5b83\u7528\u4e00\u5957\u6e05\u6670\u7684\u89c4\u5219\u56de\u7b54\u4e86\u4e09\u4e2a\u975e\u5e38\u5b9e\u9645\u7684\u95ee\u9898&#xff1a;<\/p>\n<ul>\n<li>\u4e00\u5f20\u8868\u5230\u5e95\u8be5\u653e\u54ea\u4e9b\u5b57\u6bb5&#xff1f;<\/li>\n<li>\u6570\u636e\u5197\u4f59\u4f1a\u5bfc\u81f4\u4ec0\u4e48\u6837\u7684\u5f02\u5e38&#xff1f;<\/li>\n<li>\u62c6\u8868\u4e4b\u540e&#xff0c;\u67e5\u8be2\u4ee3\u4ef7\u8981\u4ed8\u51fa\u591a\u5c11&#xff1f;<\/li>\n<\/ul>\n<p>\u672c\u6587\u4ece 1NF \u8bb2\u5230 4NF&#xff0c;\u5148\u7ed9\u51fa\u51c6\u786e\u7684\u5b9a\u4e49&#xff0c;\u518d\u8ba8\u8bba\u5de5\u7a0b\u843d\u5730\u65f6\u54ea\u4e9b\u89c4\u5219\u5e94\u5f53\u4e25\u5b88\u3001\u54ea\u4e9b\u53ef\u4ee5\u59a5\u534f\u3002<\/p>\n<h3>2. \u5fc5\u5907\u57fa\u7840&#xff1a;\u51fd\u6570\u4f9d\u8d56\u4e0e\u952e<\/h3>\n<p>\u8c08\u8303\u5f0f\u4e4b\u524d&#xff0c;\u5fc5\u987b\u5148\u628a\u4e24\u4e2a\u6982\u5ff5\u8bf4\u6e05\u695a&#xff0c;\u5426\u5219\u540e\u9762\u7684\u5224\u65ad\u90fd\u65e0\u4ece\u8c08\u8d77\u3002<\/p>\n<p>\u51fd\u6570\u4f9d\u8d56&#xff08;Functional Dependency, FD&#xff09;&#xff1a;\u5982\u679c\u5c5e\u6027\u96c6\u5408 X \u7684\u503c\u80fd\u591f\u552f\u4e00\u786e\u5b9a\u5c5e\u6027\u96c6\u5408 Y \u7684\u503c&#xff0c;\u5c31\u79f0 Y \u51fd\u6570\u4f9d\u8d56\u4e8e X&#xff0c;\u8bb0\u4f5c X \u2192 Y\u3002<\/p>\n<p>\u4e3e\u4f8b&#xff1a;\u5b66\u53f7\u80fd\u552f\u4e00\u786e\u5b9a\u5b66\u751f\u59d3\u540d&#xff0c;\u5373 \u5b66\u53f7 \u2192 \u59d3\u540d\u3002<\/p>\n<p>\u5019\u9009\u952e&#xff08;Candidate Key&#xff09;&#xff1a;\u80fd\u552f\u4e00\u6807\u8bc6\u4e00\u884c\u8bb0\u5f55\u7684\u6700\u5c0f\u5c5e\u6027\u96c6\u5408\u3002\u6240\u8c13\u300c\u6700\u5c0f\u300d&#xff0c;\u662f\u6307\u53bb\u6389\u5176\u4e2d\u4efb\u610f\u4e00\u4e2a\u5c5e\u6027\u540e&#xff0c;\u5c31\u65e0\u6cd5\u518d\u552f\u4e00\u6807\u8bc6\u4e00\u884c\u3002\u5019\u9009\u952e\u53ef\u80fd\u4e0d\u6b62\u4e00\u4e2a&#xff0c;\u8bbe\u8ba1\u65f6\u901a\u5e38\u9009\u4e00\u4e2a\u4f5c\u4e3a\u4e3b\u952e&#xff08;Primary Key&#xff09;\u3002<\/p>\n<p>\u4e3b\u5c5e\u6027 \/ \u975e\u4e3b\u5c5e\u6027&#xff1a;\u51fa\u73b0\u5728\u4efb\u4e00\u5019\u9009\u952e\u4e2d\u7684\u5c5e\u6027\u53eb\u4e3b\u5c5e\u6027&#xff1b;\u5176\u4f59\u53eb\u975e\u4e3b\u5c5e\u6027\u3002<\/p>\n<p>\u6709\u4e86\u8fd9\u4e24\u4e2a\u6982\u5ff5&#xff0c;1NF \u5230 4NF \u7684\u9012\u8fdb\u5173\u7cfb\u5c31\u53ef\u4ee5\u7528\u4e00\u53e5\u8bdd\u6982\u62ec&#xff1a;\u6bcf\u4e00\u7ea7\u8303\u5f0f\u90fd\u5728\u4e0a\u4e00\u7ea7\u7684\u57fa\u7840\u4e0a&#xff0c;\u6d88\u9664\u4e00\u7c7b\u989d\u5916\u7684\u300c\u5f02\u5e38\u4f9d\u8d56\u300d\u3002<\/p>\n<h3>3. \u7b2c\u4e00\u8303\u5f0f&#xff08;1NF&#xff09;&#xff1a;\u539f\u5b50\u6027<\/h3>\n<p>\u5b9a\u4e49&#xff1a;\u5173\u7cfb\u7684\u6bcf\u4e2a\u5c5e\u6027\u90fd\u662f\u4e0d\u53ef\u518d\u5206\u7684\u539f\u5b50\u503c\u3002\u901a\u4fd7\u5730\u8bf4&#xff0c;\u6bcf\u4e2a\u5b57\u6bb5\u53ea\u5b58\u4e00\u4e2a\u503c&#xff0c;\u4e0d\u80fd\u5b58\u6570\u7ec4\u3001\u96c6\u5408\u6216\u5d4c\u5957\u7ed3\u6784\u3002<\/p>\n<p>\u4ee5\u4e0b\u8868\u8fdd\u53cd 1NF&#xff1a;<\/p>\n<table>\n<tr>\u5b66\u751f\u8054\u7cfb\u65b9\u5f0f<\/tr>\n<tbody>\n<tr>\n<td>\u5f20\u4e09<\/td>\n<td>138xxxx, zhangsan&#064;xx.com<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u300c\u8054\u7cfb\u65b9\u5f0f\u300d\u91cc\u585e\u4e86\u4e24\u4e2a\u503c&#xff0c;\u67e5\u8be2\u548c\u66f4\u65b0\u90fd\u975e\u5e38\u522b\u626d\u3002\u6539\u6210\u6bcf\u4e00\u5217\u53ea\u5b58\u4e00\u4e2a\u539f\u5b50\u503c\u5373\u53ef\u6ee1\u8db3 1NF&#xff1a;<\/p>\n<table>\n<tr>\u5b66\u751f\u7535\u8bdd\u90ae\u7bb1<\/tr>\n<tbody>\n<tr>\n<td>\u5f20\u4e09<\/td>\n<td>138xxxx<\/td>\n<td>zhangsan&#064;xx.com<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>1NF \u662f\u73b0\u4ee3\u5173\u7cfb\u6570\u636e\u5e93\u7684\u5e95\u7ebf\u3002\u9700\u8981\u6ce8\u610f\u7684\u662f&#xff0c;\u968f\u7740 PostgreSQL \u7684\u6570\u7ec4\/JSONB\u3001MySQL \u7684 JSON \u7c7b\u578b\u6d41\u884c&#xff0c;\u300c\u5b57\u6bb5\u662f\u5426\u5fc5\u987b\u539f\u5b50\u300d\u5728\u5de5\u7a0b\u754c\u4ea7\u751f\u4e86\u65b0\u7684\u8ba8\u8bba\u3002\u4e25\u683c\u610f\u4e49\u4e0a&#xff0c;\u628a JSON \u585e\u8fdb\u4e00\u4e2a\u5b57\u6bb5\u4ecd\u7136\u662f\u5bf9 1NF \u7684\u7a81\u7834&#xff1b;\u4f46\u5728\u300c\u5217\u5185\u7ed3\u6784\u5bf9\u67e5\u8be2\u57fa\u672c\u65e0\u611f\u300d\u7684\u573a\u666f&#xff0c;\u8fd9\u79cd\u7a81\u7834\u5f80\u5f80\u5229\u5927\u4e8e\u5f0a\u3002\u8fd9\u4e00\u70b9\u653e\u5728\u7b2c 8 \u8282\u5c55\u5f00\u3002<\/p>\n<h3>4. \u7b2c\u4e8c\u8303\u5f0f&#xff08;2NF&#xff09;&#xff1a;\u6d88\u9664\u90e8\u5206\u51fd\u6570\u4f9d\u8d56<\/h3>\n<p>\u5b9a\u4e49&#xff1a;\u5728\u6ee1\u8db3 1NF \u7684\u524d\u63d0\u4e0b&#xff0c;\u6bcf\u4e2a\u975e\u4e3b\u5c5e\u6027\u5b8c\u5168\u4f9d\u8d56\u4e8e\u5019\u9009\u952e&#xff0c;\u800c\u4e0d\u5b58\u5728\u5bf9\u5019\u9009\u952e\u67d0\u4e00\u90e8\u5206\u7684\u4f9d\u8d56\u3002<\/p>\n<p>\u5178\u578b\u53cd\u4f8b\u662f\u5b66\u751f\u9009\u8bfe\u8868&#xff1a;<\/p>\n<p><span class=\"token keyword\">CREATE<\/span> <span class=\"token keyword\">TABLE<\/span> student_course <span class=\"token punctuation\">(<\/span><br \/>\n    stu_id    <span class=\"token keyword\">INT<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    course_id <span class=\"token keyword\">INT<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    stu_name  <span class=\"token keyword\">VARCHAR<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">50<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span>     <span class=\"token comment\">&#8212; \u53ea\u4f9d\u8d56 stu_id<\/span><br \/>\n    credit    <span class=\"token keyword\">INT<\/span><span class=\"token punctuation\">,<\/span>             <span class=\"token comment\">&#8212; \u53ea\u4f9d\u8d56 course_id<\/span><br \/>\n    <span class=\"token keyword\">PRIMARY<\/span> <span class=\"token keyword\">KEY<\/span> <span class=\"token punctuation\">(<\/span>stu_id<span class=\"token punctuation\">,<\/span> course_id<span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u5019\u9009\u952e\u4e3a (stu_id, course_id)&#xff0c;\u4f46 stu_name \u53ea\u4f9d\u8d56 stu_id&#xff0c;credit \u53ea\u4f9d\u8d56 course_id\u3002\u8fd9\u5c31\u662f\u90e8\u5206\u51fd\u6570\u4f9d\u8d56&#xff0c;\u8fdd\u53cd\u4e86 2NF\u3002<\/p>\n<p>\u5b83\u5e26\u6765\u7684\u95ee\u9898\u662f&#xff1a;\u4e00\u95e8\u8bfe\u7a0b\u7684\u5b66\u5206\u53d8\u4e86&#xff0c;\u8981\u6539\u5f88\u591a\u884c&#xff1b;\u8bfe\u7a0b\u8fd8\u6ca1\u5b66\u751f\u9009\u65f6&#xff0c;\u5b66\u5206\u4fe1\u606f\u65e0\u5904\u5b89\u653e\u3002\u5c06\u8868\u62c6\u4e3a\u4e09\u5f20&#xff0c;\u5c31\u80fd\u6d88\u9664\u90e8\u5206\u4f9d\u8d56&#xff1a;<\/p>\n<p><span class=\"token keyword\">CREATE<\/span> <span class=\"token keyword\">TABLE<\/span> student <span class=\"token punctuation\">(<\/span><br \/>\n    stu_id   <span class=\"token keyword\">INT<\/span> <span class=\"token keyword\">PRIMARY<\/span> <span class=\"token keyword\">KEY<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    stu_name <span class=\"token keyword\">VARCHAR<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">50<\/span><span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token keyword\">CREATE<\/span> <span class=\"token keyword\">TABLE<\/span> course <span class=\"token punctuation\">(<\/span><br \/>\n    course_id <span class=\"token keyword\">INT<\/span> <span class=\"token keyword\">PRIMARY<\/span> <span class=\"token keyword\">KEY<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    credit    <span class=\"token keyword\">INT<\/span><br \/>\n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token keyword\">CREATE<\/span> <span class=\"token keyword\">TABLE<\/span> student_course <span class=\"token punctuation\">(<\/span><br \/>\n    stu_id    <span class=\"token keyword\">INT<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    course_id <span class=\"token keyword\">INT<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token keyword\">PRIMARY<\/span> <span class=\"token keyword\">KEY<\/span> <span class=\"token punctuation\">(<\/span>stu_id<span class=\"token punctuation\">,<\/span> course_id<span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u4e00\u53e5\u8bdd\u8bb0\u5fc6&#xff1a;\u4e3b\u952e\u662f\u590d\u5408\u4e3b\u952e\u65f6&#xff0c;\u68c0\u67e5\u975e\u4e3b\u5c5e\u6027\u662f\u5426\u53ea\u4f9d\u8d56\u590d\u5408\u4e3b\u952e\u7684\u300c\u4e00\u90e8\u5206\u300d\u3002<\/p>\n<h3>5. \u7b2c\u4e09\u8303\u5f0f&#xff08;3NF&#xff09;&#xff1a;\u6d88\u9664\u4f20\u9012\u51fd\u6570\u4f9d\u8d56<\/h3>\n<p>\u5b9a\u4e49&#xff1a;\u5728\u6ee1\u8db3 2NF \u7684\u524d\u63d0\u4e0b&#xff0c;\u975e\u4e3b\u5c5e\u6027\u4e4b\u95f4\u4e0d\u5b58\u5728\u51fd\u6570\u4f9d\u8d56\u3002\u6362\u53e5\u8bdd\u8bf4&#xff0c;\u975e\u4e3b\u5c5e\u6027\u4e0d\u80fd\u901a\u8fc7\u53e6\u4e00\u4e2a\u975e\u4e3b\u5c5e\u6027\u95f4\u63a5\u4f9d\u8d56\u5019\u9009\u952e\u3002<\/p>\n<p>\u53cd\u4f8b&#xff1a;<\/p>\n<p><span class=\"token keyword\">CREATE<\/span> <span class=\"token keyword\">TABLE<\/span> student <span class=\"token punctuation\">(<\/span><br \/>\n    stu_id     <span class=\"token keyword\">INT<\/span> <span class=\"token keyword\">PRIMARY<\/span> <span class=\"token keyword\">KEY<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    dept_name  <span class=\"token keyword\">VARCHAR<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">50<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    dept_head  <span class=\"token keyword\">VARCHAR<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">50<\/span><span class=\"token punctuation\">)<\/span>   <span class=\"token comment\">&#8212; \u4f9d\u8d56 dept_name&#xff0c;\u800c\u975e\u76f4\u63a5\u4f9d\u8d56 stu_id<\/span><br \/>\n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u8fd9\u91cc\u6709 stu_id \u2192 dept_name&#xff0c;\u540c\u65f6 dept_name \u2192 dept_head&#xff0c;\u4e8e\u662f stu_id \u2192 dept_head \u662f\u4e00\u6761\u4f20\u9012\u4f9d\u8d56\u3002\u8fdd\u53cd 3NF \u7684\u540e\u679c\u662f&#xff1a;\u7cfb\u4e3b\u4efb\u6362\u4eba\u65f6&#xff0c;\u8981\u66f4\u65b0\u8fd9\u4e2a\u7cfb\u6240\u6709\u5b66\u751f\u7684\u8bb0\u5f55&#xff1b;\u7cfb\u91cc\u6682\u65f6\u6ca1\u5b66\u751f\u65f6&#xff0c;\u7cfb\u4e0e\u7cfb\u4e3b\u4efb\u7684\u6620\u5c04\u4e5f\u4fdd\u5b58\u4e0d\u4e86\u3002<\/p>\n<p>\u6d88\u9664\u4f20\u9012\u4f9d\u8d56\u7684\u65b9\u6cd5\u662f\u62c6\u51fa\u90e8\u95e8\u8868&#xff1a;<\/p>\n<p><span class=\"token keyword\">CREATE<\/span> <span class=\"token keyword\">TABLE<\/span> dept <span class=\"token punctuation\">(<\/span><br \/>\n    dept_name  <span class=\"token keyword\">VARCHAR<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">50<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">PRIMARY<\/span> <span class=\"token keyword\">KEY<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    dept_head  <span class=\"token keyword\">VARCHAR<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">50<\/span><span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token keyword\">CREATE<\/span> <span class=\"token keyword\">TABLE<\/span> student <span class=\"token punctuation\">(<\/span><br \/>\n    stu_id     <span class=\"token keyword\">INT<\/span> <span class=\"token keyword\">PRIMARY<\/span> <span class=\"token keyword\">KEY<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    dept_name  <span class=\"token keyword\">VARCHAR<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">50<\/span><span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>3NF \u662f\u5de5\u7a0b\u4e0a\u6700\u5e38\u89c1\u7684\u300c\u53ca\u683c\u7ebf\u300d\u3002\u7edd\u5927\u591a\u6570 OLTP \u4e1a\u52a1\u8868&#xff0c;\u628a 3NF \u505a\u5230\u4f4d&#xff0c;\u5197\u4f59\u548c\u5f02\u5e38\u5c31\u57fa\u672c\u53ef\u63a7\u4e86\u3002<\/p>\n<h3>6. BC \u8303\u5f0f&#xff08;BCNF&#xff09;&#xff1a;\u6bd4 3NF \u66f4\u4e25\u683c\u7684\u4e00\u6b65<\/h3>\n<p>BCNF&#xff08;Boyce-Codd Normal Form&#xff09;\u5e38\u88ab\u7b80\u5355\u8bf4\u6210\u300c\u52a0\u5f3a\u7248 3NF\u300d\u3002\u51c6\u786e\u7684\u533a\u522b\u5728\u4e8e&#xff1a;3NF \u53ea\u7ea6\u675f\u975e\u4e3b\u5c5e\u6027&#xff0c;\u800c BCNF \u8fde\u4e3b\u5c5e\u6027\u4e5f\u8981\u7ea6\u675f\u3002<\/p>\n<p>\u5b9a\u4e49&#xff1a;\u5bf9\u4e8e\u5173\u7cfb\u4e2d\u4efb\u610f\u975e\u5e73\u51e1\u51fd\u6570\u4f9d\u8d56 X \u2192 Y&#xff0c;X \u90fd\u5fc5\u987b\u662f\u8d85\u952e&#xff08;\u5373 X \u80fd\u552f\u4e00\u786e\u5b9a\u4e00\u884c&#xff09;\u3002<\/p>\n<p>\u6ce8\u610f&#xff1a;3NF \u5141\u8bb8\u4e00\u79cd\u4f8b\u5916\u2014\u2014\u5f53 Y \u662f\u4e3b\u5c5e\u6027\u65f6&#xff0c;X \u53ef\u4ee5\u4e0d\u662f\u8d85\u952e\u3002BCNF \u4e0d\u5141\u8bb8\u4efb\u4f55\u4f8b\u5916\u3002<\/p>\n<p>\u7ecf\u5178\u53cd\u4f8b\u662f\u300c\u5b66\u751f\u2014\u6559\u5e08\u2014\u8bfe\u7a0b\u300d\u8868&#xff1a;<\/p>\n<p><span class=\"token keyword\">CREATE<\/span> <span class=\"token keyword\">TABLE<\/span> teaching <span class=\"token punctuation\">(<\/span><br \/>\n    stu_id    <span class=\"token keyword\">INT<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    teacher   <span class=\"token keyword\">VARCHAR<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">50<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    course    <span class=\"token keyword\">VARCHAR<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">50<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token keyword\">PRIMARY<\/span> <span class=\"token keyword\">KEY<\/span> <span class=\"token punctuation\">(<\/span>stu_id<span class=\"token punctuation\">,<\/span> teacher<span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u4e1a\u52a1\u7ea6\u675f\u4e3a&#xff1a;<\/p>\n<ul>\n<li>\u6bcf\u4e2a\u6559\u5e08\u53ea\u6559\u4e00\u95e8\u8bfe&#xff1a;teacher \u2192 course&#xff1b;<\/li>\n<li>\u6bcf\u540d\u5b66\u751f\u6bcf\u95e8\u8bfe\u53ea\u6709\u4e00\u4f4d\u6559\u5e08&#xff1a;(stu_id, course) \u2192 teacher\u3002<\/li>\n<\/ul>\n<p>\u6b64\u65f6\u5019\u9009\u952e\u6709\u4e24\u4e2a&#xff1a;(stu_id, teacher) \u548c (stu_id, course)\u3002teacher \u548c course \u90fd\u662f\u4e3b\u5c5e\u6027\u3002\u51fd\u6570\u4f9d\u8d56 teacher \u2192 course \u4e2d&#xff0c;teacher \u4e0d\u662f\u8d85\u952e&#xff0c;\u56e0\u6b64\u8fdd\u53cd BCNF&#xff1b;\u4f46\u7531\u4e8e course \u662f\u4e3b\u5c5e\u6027&#xff0c;\u5b83\u5e76\u6ca1\u6709\u8fdd\u53cd 3NF\u3002<\/p>\n<p>\u8fd9\u5c31\u662f 3NF \u4e0e BCNF \u7684\u771f\u5b9e\u7f1d\u9699&#xff1a;\u4e3b\u5c5e\u6027\u4e4b\u95f4\u4e5f\u53ef\u80fd\u5b58\u5728\u4e0d\u8be5\u6709\u7684\u4f9d\u8d56\u3002\u8981\u6ee1\u8db3 BCNF&#xff0c;\u9700\u62c6\u6210&#xff1a;<\/p>\n<p><span class=\"token keyword\">CREATE<\/span> <span class=\"token keyword\">TABLE<\/span> teacher_course <span class=\"token punctuation\">(<\/span><br \/>\n    teacher <span class=\"token keyword\">VARCHAR<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">50<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">PRIMARY<\/span> <span class=\"token keyword\">KEY<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    course  <span class=\"token keyword\">VARCHAR<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">50<\/span><span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token keyword\">CREATE<\/span> <span class=\"token keyword\">TABLE<\/span> stu_teacher <span class=\"token punctuation\">(<\/span><br \/>\n    stu_id  <span class=\"token keyword\">INT<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    teacher <span class=\"token keyword\">VARCHAR<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">50<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token keyword\">PRIMARY<\/span> <span class=\"token keyword\">KEY<\/span> <span class=\"token punctuation\">(<\/span>stu_id<span class=\"token punctuation\">,<\/span> teacher<span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u5b9e\u9645\u9879\u76ee\u4e2d&#xff0c;\u80fd\u81ea\u7136\u843d\u5230 BCNF \u7684\u8868\u5e76\u4e0d\u591a&#xff0c;\u591a\u6570\u4e1a\u52a1\u8868\u505a\u5230 3NF \u5df2\u7ecf\u8db3\u591f&#xff0c;\u56e0\u4e3a\u300c\u4e3b\u5c5e\u6027\u4e4b\u95f4\u7684\u4f9d\u8d56\u300d\u5728\u771f\u5b9e\u6a21\u578b\u91cc\u76f8\u5bf9\u5c11\u89c1\u3002\u4f46\u7406\u89e3 BCNF&#xff0c;\u80fd\u5e2e\u4f60\u8bc6\u522b\u90a3\u4e9b\u300c\u770b\u4f3c\u5408\u89c4\u5374\u603b\u89c9\u5f97\u522b\u626d\u300d\u7684\u8868\u7ed3\u6784\u3002<\/p>\n<h3>7. \u7b2c\u56db\u8303\u5f0f&#xff08;4NF&#xff09;&#xff1a;\u76f4\u9762\u591a\u503c\u4f9d\u8d56<\/h3>\n<p>4NF \u9762\u5bf9\u7684\u95ee\u9898&#xff0c;\u7528\u51fd\u6570\u4f9d\u8d56\u5df2\u7ecf\u65e0\u6cd5\u63cf\u8ff0\u4e86\u3002<\/p>\n<p>\u591a\u503c\u4f9d\u8d56&#xff08;Multivalued Dependency, MVD&#xff09;&#xff1a;\u5728\u5173\u7cfb R(X, Y, Z) \u4e2d&#xff0c;\u82e5\u7ed9\u5b9a X \u7684\u503c&#xff0c;Y \u7684\u53d6\u503c\u96c6\u5408\u4e0e Z \u7684\u53d6\u503c\u96c6\u5408\u76f8\u4e92\u72ec\u7acb&#xff0c;\u5219\u79f0 X \u2192\u2192 Y\u3002\u4f8b\u5982\u300c\u5458\u5de5\u4f1a\u8bf4\u591a\u95e8\u8bed\u8a00&#xff0c;\u4e5f\u638c\u63e1\u591a\u9879\u6280\u80fd&#xff0c;\u8bed\u8a00\u548c\u6280\u80fd\u5f7c\u6b64\u72ec\u7acb\u300d&#xff0c;\u5c31\u5b58\u5728 emp_id \u2192\u2192 skill \u548c emp_id \u2192\u2192 language\u3002<\/p>\n<p>\u5178\u578b\u53cd\u4f8b&#xff1a;<\/p>\n<table>\n<tr>emp_idskilllanguage<\/tr>\n<tbody>\n<tr>\n<td>001<\/td>\n<td>Java<\/td>\n<td>\u4e2d\u6587<\/td>\n<\/tr>\n<tr>\n<td>001<\/td>\n<td>Java<\/td>\n<td>\u82f1\u8bed<\/td>\n<\/tr>\n<tr>\n<td>001<\/td>\n<td>Python<\/td>\n<td>\u4e2d\u6587<\/td>\n<\/tr>\n<tr>\n<td>001<\/td>\n<td>Python<\/td>\n<td>\u82f1\u8bed<\/td>\n<\/tr>\n<tr>\n<td>002<\/td>\n<td>SQL<\/td>\n<td>\u4e2d\u6587<\/td>\n<\/tr>\n<tr>\n<td>002<\/td>\n<td>SQL<\/td>\n<td>\u82f1\u8bed<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u5458\u5de5 001 \u4f1a Java\/Python\u3001\u8bf4\u4e2d\u82f1\u53cc\u8bed\u3002\u4e3a\u4e86\u7ef4\u62a4\u300c\u6280\u80fd\u4e0e\u8bed\u8a00\u76f8\u4e92\u72ec\u7acb\u300d\u8fd9\u4e00\u4e8b\u5b9e&#xff0c;\u5fc5\u987b\u7528\u7b1b\u5361\u5c14\u79ef\u8865\u5168\u6240\u6709\u7ec4\u5408&#xff1b;\u5c11\u4e00\u884c&#xff0c;\u6570\u636e\u5c31\u4e0d\u4e00\u81f4\u3002\u8fd9\u7c7b\u5197\u4f59\u6b63\u662f\u591a\u503c\u4f9d\u8d56\u9020\u6210\u7684\u3002<\/p>\n<p>\u5b9a\u4e49&#xff1a;\u5728\u6ee1\u8db3 BCNF \u7684\u524d\u63d0\u4e0b&#xff0c;\u5bf9\u4e8e\u4efb\u610f\u975e\u5e73\u51e1\u591a\u503c\u4f9d\u8d56 X \u2192\u2192 Y&#xff0c;X \u90fd\u5fc5\u987b\u662f\u8d85\u952e\u3002<\/p>\n<p>\u4e0a\u8868\u7684\u4e3b\u952e\u662f (emp_id, skill, language)&#xff0c;\u5168\u8868\u90fd\u662f\u4e3b\u5c5e\u6027&#xff0c;\u56e0\u6b64\u5b83\u6ee1\u8db3 BCNF&#xff0c;\u4f46 emp_id \u2192\u2192 skill \u4e2d\u7684 emp_id \u4e0d\u662f\u8d85\u952e&#xff0c;\u8fdd\u53cd 4NF\u3002<\/p>\n<p>\u5206\u89e3\u4e3a\u4e24\u5f20\u8868\u5373\u53ef\u6d88\u9664&#xff1a;<\/p>\n<p><span class=\"token keyword\">CREATE<\/span> <span class=\"token keyword\">TABLE<\/span> emp_skill <span class=\"token punctuation\">(<\/span><br \/>\n    emp_id <span class=\"token keyword\">INT<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    skill  <span class=\"token keyword\">VARCHAR<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">50<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token keyword\">PRIMARY<\/span> <span class=\"token keyword\">KEY<\/span> <span class=\"token punctuation\">(<\/span>emp_id<span class=\"token punctuation\">,<\/span> skill<span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token keyword\">CREATE<\/span> <span class=\"token keyword\">TABLE<\/span> emp_language <span class=\"token punctuation\">(<\/span><br \/>\n    emp_id   <span class=\"token keyword\">INT<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token keyword\">language<\/span> <span class=\"token keyword\">VARCHAR<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">50<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token keyword\">PRIMARY<\/span> <span class=\"token keyword\">KEY<\/span> <span class=\"token punctuation\">(<\/span>emp_id<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">language<\/span><span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>4NF \u5904\u7406\u7684\u662f\u300c\u540c\u4e00\u884c\u91cc\u585e\u4e86\u591a\u4e2a\u5f7c\u6b64\u72ec\u7acb\u7684\u4e00\u5bf9\u591a\u5173\u7cfb\u300d\u3002\u8fd9\u7c7b\u95ee\u9898\u5728\u5b9e\u8df5\u4e2d\u901a\u5e38\u8868\u73b0\u4e3a&#xff1a;\u4e00\u5f20\u8868\u540c\u65f6\u627f\u62c5\u4e86\u591a\u4e2a\u4e92\u4e0d\u76f8\u5e72\u7684\u96c6\u5408\u5c5e\u6027\u3002\u4e00\u65e6\u8bc6\u522b\u51fa\u8fd9\u79cd\u72ec\u7acb\u6027&#xff0c;\u62c6\u5f00\u5f80\u5f80\u6bd4\u5f3a\u884c\u5408\u5728\u4e00\u8d77\u66f4\u81ea\u7136\u3002<\/p>\n<h3>8. \u5de5\u7a0b\u53d6\u820d&#xff1a;\u8303\u5f0f\u4e0d\u662f\u6559\u6761<\/h3>\n<p>\u7406\u8bba\u8bb2\u5b8c&#xff0c;\u56de\u5230\u90a3\u4e2a\u6700\u73b0\u5b9e\u7684\u95ee\u9898&#xff1a;\u5b9e\u9645\u5efa\u8868&#xff0c;\u5230\u5e95\u8981\u9075\u5b88\u5230\u4ec0\u4e48\u7a0b\u5ea6&#xff1f;<\/p>\n<h4>8.1 \u89c4\u8303\u5316\u4e0d\u662f\u514d\u8d39\u7684<\/h4>\n<p>\u6bcf\u63d0\u5347\u4e00\u7ea7\u8303\u5f0f&#xff0c;\u901a\u5e38\u90fd\u610f\u5473\u7740\u62c6\u51fa\u66f4\u591a\u8868\u3002\u8868\u62c6\u5f97\u8d8a\u7ec6&#xff0c;\u5199\u5165\u65f6\u7684\u5197\u4f59\u548c\u5f02\u5e38\u8d8a\u5c11&#xff0c;\u4f46\u67e5\u8be2\u65f6\u8981 JOIN \u7684\u8868\u5c31\u8d8a\u591a\u3002\u5728\u6570\u636e\u91cf\u5927\u3001\u5e76\u53d1\u9ad8\u7684\u573a\u666f\u91cc&#xff0c;\u591a\u8868 JOIN \u7684\u4ee3\u4ef7\u53ef\u80fd\u8fdc\u9ad8\u4e8e\u5197\u4f59\u5e26\u6765\u7684\u7ef4\u62a4\u6210\u672c\u3002<\/p>\n<p>\u56e0\u6b64&#xff0c;\u89c4\u8303\u5316\u7684\u6536\u76ca\u662f\u6709\u4e0a\u9650\u7684&#xff1a;\u5f53\u5197\u4f59\u53ef\u63a7\u3001\u4e1a\u52a1\u903b\u8f91\u4e0d\u590d\u6742\u65f6&#xff0c;\u4e00\u5473\u8ffd\u6c42\u9ad8\u8303\u5f0f\u53ea\u4f1a\u5f97\u5230\u4e00\u5957\u96be\u5199\u3001\u96be\u8c03\u3001\u6027\u80fd\u5e73\u5eb8\u7684\u8868\u7ed3\u6784\u3002<\/p>\n<h4>8.2 \u5e38\u89c1\u7684\u843d\u5730\u59ff\u6001<\/h4>\n<p>\u5404\u573a\u666f\u5bf9\u8303\u5f0f\u7684\u8981\u6c42\u5927\u81f4\u5982\u4e0b&#xff1a;<\/p>\n<table>\n<tr>\u573a\u666f\u63a8\u8350\u7ea7\u522b\u539f\u56e0<\/tr>\n<tbody>\n<tr>\n<td>OLTP \u6838\u5fc3\u4e1a\u52a1<\/td>\n<td>3NF \/ BCNF<\/td>\n<td>\u5199\u5165\u9891\u7e41&#xff0c;\u6700\u770b\u91cd\u4e00\u81f4\u6027\u4e0e\u5f02\u5e38\u63a7\u5236<\/td>\n<\/tr>\n<tr>\n<td>\u62a5\u8868 \/ \u5206\u6790\u5bbd\u8868<\/td>\n<td>1NF \/ \u90e8\u5206\u53cd\u89c4\u8303\u5316<\/td>\n<td>\u8bfb\u591a\u5199\u5c11&#xff0c;\u7528\u5197\u4f59\u6362\u67e5\u8be2\u901f\u5ea6<\/td>\n<\/tr>\n<tr>\n<td>\u65e5\u5fd7 \/ \u57cb\u70b9<\/td>\n<td>1NF \u5373\u53ef<\/td>\n<td>\u57fa\u672c\u65e0\u66f4\u65b0&#xff0c;\u5197\u4f59\u5f71\u54cd\u5c0f<\/td>\n<\/tr>\n<tr>\n<td>\u7f13\u5b58\u5c42 \/ \u6587\u6863\u5b58\u50a8<\/td>\n<td>\u4e0d\u4e25\u683c\u8981\u6c42<\/td>\n<td>\u6570\u636e\u4ee5\u805a\u5408\u7c92\u5ea6\u6574\u4f53\u8bfb\u5199<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h4>8.3 \u5bf9 1NF \u7684\u91cd\u65b0\u5ba1\u89c6<\/h4>\n<p>JSON \u5b57\u6bb5\u662f\u5bf9 1NF \u7684\u76f4\u63a5\u6311\u6218\u3002\u4e00\u4e2a\u7ecf\u5178\u573a\u666f\u662f\u300c\u5546\u54c1\u6269\u5c55\u5c5e\u6027\u300d&#xff1a;\u4e0d\u540c\u54c1\u7c7b\u7684\u5546\u54c1\u5c5e\u6027\u5dee\u5f02\u5de8\u5927&#xff0c;\u786c\u62c6\u6210 EAV&#xff08;\u5b9e\u4f53-\u5c5e\u6027-\u503c&#xff09;\u4e09\u5f20\u8868\u6ee1\u8db3\u8303\u5f0f&#xff0c;\u4f46\u67e5\u8be2\u548c\u5199\u5165\u90fd\u975e\u5e38\u75db\u82e6&#xff1b;\u76f4\u63a5\u5b58\u4e00\u4e2a JSON \u5b57\u6bb5&#xff0c;\u53cd\u800c\u662f\u6027\u4ef7\u6bd4\u6700\u9ad8\u7684\u65b9\u6848\u3002<\/p>\n<p>\u8fd9\u91cc\u7684\u5224\u65ad\u6807\u51c6\u4e0d\u662f\u300c\u662f\u5426\u6ee1\u8db3 1NF\u300d&#xff0c;\u800c\u662f&#xff1a;\u8fd9\u4e2a\u5217\u5185\u7ed3\u6784\u662f\u5426\u9700\u8981\u88ab\u6570\u636e\u5e93\u9891\u7e41\u68c0\u7d22\u3001\u7ea6\u675f\u548c\u66f4\u65b0\u3002\u5982\u679c\u53ea\u662f\u6574\u4f53\u5b58\u53d6&#xff0c;JSON \u5b8c\u5168\u53ef\u7528&#xff1b;\u5982\u679c\u9700\u8981\u6309\u5217\u5185\u5b57\u6bb5\u505a\u8fc7\u6ee4\u3001\u6392\u5e8f\u6216\u552f\u4e00\u7ea6\u675f&#xff0c;\u90a3\u6700\u597d\u8001\u8001\u5b9e\u5b9e\u62c6\u6210\u72ec\u7acb\u5217\u3002<\/p>\n<h3>9. \u843d\u5730\u5efa\u8bae&#xff1a;\u4e00\u4e2a\u53ef\u64cd\u4f5c\u7684\u5224\u65ad\u8def\u5f84<\/h3>\n<p>\u9762\u5bf9\u4e00\u5f20\u65b0\u8868&#xff0c;\u5efa\u8bae\u6309\u4e0b\u9762\u987a\u5e8f\u81ea\u68c0&#xff0c;\u800c\u4e0d\u662f\u4ece 1NF \u673a\u68b0\u5730\u63a8\u5230\u5e95&#xff1a;<\/p>\n<li>\u5148\u6ee1\u8db3 1NF&#xff1a;\u5b57\u6bb5\u662f\u5426\u8fd8\u585e\u7740\u6570\u7ec4\/\u5d4c\u5957\u7ed3\u6784&#xff1f;\u5982\u679c\u662f&#xff0c;\u5224\u65ad\u8fd9\u4e2a\u7ed3\u6784\u662f\u5426\u9700\u8981\u5355\u72ec\u67e5\u8be2\u548c\u7ea6\u675f\u3002<\/li>\n<li>\u8bc6\u522b\u5019\u9009\u952e&#xff1a;\u660e\u786e\u54ea\u4e9b\u5c5e\u6027\u7ec4\u5408\u80fd\u552f\u4e00\u786e\u5b9a\u4e00\u884c\u3002\u627e\u4e0d\u5230\u4e3b\u952e\u7684\u8868&#xff0c;\u5f80\u5f80\u4e00\u5f00\u59cb\u5c31\u8bbe\u8ba1\u9519\u4e86\u3002<\/li>\n<li>\u68c0\u67e5 2NF&#xff1a;\u4e3b\u952e\u662f\u590d\u5408\u952e\u65f6&#xff0c;\u6bcf\u4e2a\u975e\u4e3b\u5c5e\u6027\u662f\u5426\u53ea\u4f9d\u8d56\u4e3b\u952e\u7684\u4e00\u90e8\u5206&#xff1f;<\/li>\n<li>\u68c0\u67e5 3NF&#xff1a;\u975e\u4e3b\u5c5e\u6027\u4e4b\u95f4\u662f\u5426\u5b58\u5728\u4f9d\u8d56\u94fe\u6761&#xff1f;&#xff08;A \u2192 B \u2192 C&#xff09;<\/li>\n<li>\u68c0\u67e5 BCNF&#xff08;\u53ef\u9009&#xff09;&#xff1a;\u4e3b\u5c5e\u6027\u4e4b\u95f4\u662f\u5426\u4e5f\u6709\u51fd\u6570\u4f9d\u8d56&#xff1f;\u591a\u6570\u4e1a\u52a1\u6a21\u578b\u5230\u8fd9\u4e00\u6b65\u5df2\u7ecf\u591f\u7528\u3002<\/li>\n<li>\u68c0\u67e5 4NF&#xff08;\u6309\u9700&#xff09;&#xff1a;\u4e00\u884c\u91cc\u662f\u5426\u540c\u65f6\u585e\u4e86\u591a\u4e2a\u5f7c\u6b64\u72ec\u7acb\u7684\u4e00\u5bf9\u591a\u96c6\u5408&#xff1f;<\/li>\n<p>\u6bcf\u62c6\u4e00\u6b21\u8868&#xff0c;\u90fd\u95ee\u81ea\u5df1\u4e00\u53e5&#xff1a;\u8fd9\u5c42\u62c6\u5206\u6362\u6765\u7684\u662f\u4e00\u81f4\u6027\u63d0\u5347&#xff0c;\u8fd8\u662f\u5f92\u589e JOIN&#xff1f; \u5982\u679c\u7b54\u6848\u504f\u5411\u540e\u8005&#xff0c;\u4e14\u5197\u4f59\u5e26\u6765\u7684\u66f4\u65b0\u5f02\u5e38\u5728\u4e1a\u52a1\u4e0a\u53ef\u63a5\u53d7&#xff0c;\u90a3\u4e48\u4fdd\u6301\u73b0\u72b6\u5c31\u662f\u5408\u7406\u7684\u5de5\u7a0b\u51b3\u7b56\u3002<\/p>\n<h3>10. \u603b\u7ed3<\/h3>\n<p>\u8303\u5f0f\u7406\u8bba\u63d0\u4f9b\u7684\u662f\u4e00\u5957\u7cbe\u786e\u7684\u300c\u8868\u7ed3\u6784\u8bca\u65ad\u8bed\u8a00\u300d&#xff1a;\u51fd\u6570\u4f9d\u8d56\u3001\u90e8\u5206\u4f9d\u8d56\u3001\u4f20\u9012\u4f9d\u8d56\u3001\u591a\u503c\u4f9d\u8d56&#xff0c;\u5206\u522b\u5bf9\u5e94 2NF\u30013NF\u3001BCNF\u30014NF \u8981\u6d88\u9664\u7684\u5f02\u5e38\u3002<\/p>\n<ul>\n<li>1NF \u7ba1\u539f\u5b50\u6027&#xff1b;<\/li>\n<li>2NF \u7ba1\u590d\u5408\u952e\u4e0b\u7684\u90e8\u5206\u4f9d\u8d56&#xff1b;<\/li>\n<li>3NF \u7ba1\u975e\u4e3b\u5c5e\u6027\u95f4\u7684\u4f20\u9012\u4f9d\u8d56&#xff1b;<\/li>\n<li>BCNF \u628a\u7ea6\u675f\u6269\u5c55\u5230\u4e3b\u5c5e\u6027&#xff1b;<\/li>\n<li>4NF \u5904\u7406\u591a\u503c\u4f9d\u8d56\u3002<\/li>\n<\/ul>\n<p>\u4f46\u5b83\u4eec\u4ece\u6765\u4e0d\u662f\u8d8a\u9ad8\u8d8a\u597d\u7684\u6559\u6761\u3002\u5de5\u7a0b\u4e0a\u7684\u6210\u719f\u505a\u6cd5\u662f&#xff1a;\u4ee5 3NF\/BCNF \u4e3a OLTP 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