{"id":647,"date":"2019-12-30T19:17:29","date_gmt":"2019-12-30T11:17:29","guid":{"rendered":"http:\/\/www.wdsos.com\/index.php\/2019\/12\/30\/drop%e3%80%81truncate%e5%92%8cdelete%e7%9a%84%e5%8c%ba%e5%88%ab\/"},"modified":"2024-10-31T22:44:14","modified_gmt":"2024-10-31T14:44:14","slug":"drop%e3%80%81truncate%e5%92%8cdelete%e7%9a%84%e5%8c%ba%e5%88%ab","status":"publish","type":"post","link":"http:\/\/www.jointchina.com\/index.php\/%e6%88%90%e5%8a%9f%e6%a1%88%e4%be%8b\/server-case\/647\/","title":{"rendered":"drop\u3001truncate\u548cdelete\u7684\u533a\u522b"},"content":{"rendered":"

drop\u3001truncate\u548cdelete\u7684\u533a\u522b<\/span><\/strong><\/h1>\n

\uff081\uff09DELETE\u8bed\u53e5\u6267\u884c\u5220\u9664\u7684\u8fc7\u7a0b\u662f\u6bcf\u6b21\u4ece\u8868\u4e2d\u5220\u9664\u4e00\u884c\uff0c\u5e76\u4e14\u540c\u65f6\u5c06\u8be5\u884c\u7684\u5220\u9664\u64cd\u4f5c\u4f5c\u4e3a\u4e8b\u52a1\u8bb0\u5f55\u5728\u65e5\u5fd7\u4e2d\u4fdd\u5b58\u4ee5\u4fbf\u8fdb\u884c\u8fdb\u884c\u56de\u6eda\u64cd\u4f5c\u3002<\/p>\n

   TRUNCATE TABLE \u5219\u4e00\u6b21\u6027\u5730\u4ece\u8868\u4e2d\u5220\u9664\u6240\u6709\u7684\u6570\u636e\u5e76\u4e0d\u628a\u5355\u72ec\u7684\u5220\u9664\u64cd\u4f5c\u8bb0\u5f55\u8bb0\u5165\u65e5\u5fd7\u4fdd\u5b58\uff0c\u5220\u9664\u884c\u662f\u4e0d\u80fd\u6062\u590d\u7684\u3002\u5e76\u4e14\u5728\u5220\u9664\u7684\u8fc7\u7a0b\u4e2d\u4e0d\u4f1a\u6fc0\u6d3b\u4e0e\u8868\u6709\u5173\u7684\u5220\u9664\u89e6\u53d1\u5668\u3002\u6267\u884c\u901f\u5ea6\u5feb\u3002<\/p>\n

\uff082\uff09\u8868\u548c\u7d22\u5f15\u6240\u5360\u7a7a\u95f4\u3002<\/p>\n

   \u5f53\u8868\u88abTRUNCATE \u540e\uff0c\u8fd9\u4e2a\u8868\u548c\u7d22\u5f15\u6240\u5360\u7528\u7684\u7a7a\u95f4\u4f1a\u6062\u590d\u5230\u521d\u59cb\u5927\u5c0f\uff0c<\/p>\n

   DELETE\u64cd\u4f5c\u4e0d\u4f1a\u51cf\u5c11\u8868\u6216\u7d22\u5f15\u6240\u5360\u7528\u7684\u7a7a\u95f4\u3002<\/p>\n

   drop\u8bed\u53e5\u5c06\u8868\u6240\u5360\u7528\u7684\u7a7a\u95f4\u5168\u91ca\u653e\u6389\u3002<\/p>\n

\uff083\uff09\u4e00\u822c\u800c\u8a00\uff0cdrop > truncate > delete<\/p>\n

\uff084\uff09\u5e94\u7528\u8303\u56f4\u3002<\/p>\n

    TRUNCATE \u53ea\u80fd\u5bf9TABLE\uff1b         DELETE\u53ef\u4ee5\u662ftable\u548cview<\/p>\n

\uff085\uff09TRUNCATE \u548cDELETE\u53ea\u5220\u9664\u6570\u636e\uff0c DROP\u5219\u5220\u9664\u6574\u4e2a\u8868\uff08\u7ed3\u6784\u548c\u6570\u636e\uff09\u3002<\/p>\n

\uff086\uff09truncate\u4e0e\u4e0d\u5e26where\u7684delete \uff1a\u53ea\u5220\u9664\u6570\u636e\uff0c\u800c\u4e0d\u5220\u9664\u8868\u7684\u7ed3\u6784\uff08\u5b9a\u4e49\uff09drop\u8bed\u53e5\u5c06\u5220\u9664\u8868\u7684\u7ed3\u6784\u88ab\u4f9d\u8d56\u7684\u7ea6\u675f\uff08constrain),\u89e6\u53d1\u5668\uff08trigger)\u7d22\u5f15\uff08index);\u4f9d\u8d56\u4e8e\u8be5\u8868\u7684\u5b58\u50a8\u8fc7\u7a0b\/\u51fd\u6570\u5c06\u88ab\u4fdd\u7559\uff0c\u4f46\u5176\u72b6\u6001\u4f1a\u53d8\u4e3a\uff1ainvalid\u3002<\/p>\n

\uff087\uff09delete\u8bed\u53e5\u4e3aDML\uff08data maintain Language),\u8fd9\u4e2a\u64cd\u4f5c\u4f1a\u88ab\u653e\u5230 rollback segment\u4e2d,\u4e8b\u52a1\u63d0\u4ea4\u540e\u624d\u751f\u6548\u3002\u5982\u679c\u6709\u76f8\u5e94\u7684 tigger,\u6267\u884c\u7684\u65f6\u5019\u5c06\u88ab\u89e6\u53d1\u3002<\/p>\n

\uff088\uff09truncate\u3001drop\u662fDLL\uff08data define language),\u64cd\u4f5c\u7acb\u5373\u751f\u6548\uff0c\u539f\u6570\u636e\u4e0d\u653e\u5230 rollback segment\u4e2d\uff0c\u4e0d\u80fd\u56de\u6eda<\/p>\n

\uff089\uff09\u5728\u6ca1\u6709\u5907\u4efd\u60c5\u51b5\u4e0b\uff0c\u8c28\u614e\u4f7f\u7528 drop \u4e0e truncate\u3002\u8981\u5220\u9664\u90e8\u5206\u6570\u636e\u884c\u91c7\u7528delete\u4e14\u6ce8\u610f\u7ed3\u5408where\u6765\u7ea6\u675f\u5f71\u54cd\u8303\u56f4\u3002\u56de\u6eda\u6bb5\u8981\u8db3\u591f\u5927\u3002\u8981\u5220\u9664\u8868\u7528drop;\u82e5\u60f3\u4fdd\u7559\u8868\u800c\u5c06\u8868\u4e2d\u6570\u636e\u5220\u9664\uff0c\u5982\u679c\u4e8e\u4e8b\u52a1\u65e0\u5173\uff0c\u7528truncate\u5373\u53ef\u5b9e\u73b0\u3002\u5982\u679c\u548c\u4e8b\u52a1\u6709\u5173\uff0c\u6216\u8001\u5e08\u60f3\u89e6\u53d1trigger,\u8fd8\u662f\u7528delete\u3002<\/p>\n

\uff0810\uff09 Truncate table \u8868\u540d \u901f\u5ea6\u5feb,\u800c\u4e14\u6548\u7387\u9ad8,\u56e0\u4e3a: 
truncate table \u5728\u529f\u80fd\u4e0a\u4e0e\u4e0d\u5e26 WHERE \u5b50\u53e5\u7684 DELETE \u8bed\u53e5\u76f8\u540c\uff1a\u4e8c\u8005\u5747\u5220\u9664\u8868\u4e2d\u7684\u5168\u90e8\u884c\u3002\u4f46 TRUNCATE TABLE \u6bd4 DELETE \u901f\u5ea6\u5feb\uff0c\u4e14\u4f7f\u7528\u7684\u7cfb\u7edf\u548c\u4e8b\u52a1\u65e5\u5fd7\u8d44\u6e90\u5c11\u3002DELETE \u8bed\u53e5\u6bcf\u6b21\u5220\u9664\u4e00\u884c\uff0c\u5e76\u5728\u4e8b\u52a1\u65e5\u5fd7\u4e2d\u4e3a\u6240\u5220\u9664\u7684\u6bcf\u884c\u8bb0\u5f55\u4e00\u9879\u3002TRUNCATE TABLE \u901a\u8fc7\u91ca\u653e\u5b58\u50a8\u8868\u6570\u636e\u6240\u7528\u7684\u6570\u636e\u9875\u6765\u5220\u9664\u6570\u636e\uff0c\u5e76\u4e14\u53ea\u5728\u4e8b\u52a1\u65e5\u5fd7\u4e2d\u8bb0\u5f55\u9875\u7684\u91ca\u653e\u3002 <\/p>\n

\uff0811\uff09 TRUNCATE TABLE \u5220\u9664\u8868\u4e2d\u7684\u6240\u6709\u884c\uff0c\u4f46\u8868\u7ed3\u6784\u53ca\u5176\u5217\u3001\u7ea6\u675f\u3001\u7d22\u5f15\u7b49\u4fdd\u6301\u4e0d\u53d8\u3002\u65b0\u884c\u6807\u8bc6\u6240\u7528\u7684\u8ba1\u6570\u503c\u91cd\u7f6e\u4e3a\u8be5\u5217\u7684\u79cd\u5b50\u3002\u5982\u679c\u60f3\u4fdd\u7559\u6807\u8bc6\u8ba1\u6570\u503c\uff0c\u8bf7\u6539\u7528 DELETE\u3002\u5982\u679c\u8981\u5220\u9664\u8868\u5b9a\u4e49\u53ca\u5176\u6570\u636e\uff0c\u8bf7\u4f7f\u7528 DROP TABLE \u8bed\u53e5\u3002 <\/p>\n

\uff0812\uff09 \u5bf9\u4e8e\u7531 FOREIGN KEY \u7ea6\u675f\u5f15\u7528\u7684\u8868\uff0c\u4e0d\u80fd\u4f7f\u7528 TRUNCATE TABLE\uff0c\u800c\u5e94\u4f7f\u7528\u4e0d\u5e26 WHERE \u5b50\u53e5\u7684 DELETE \u8bed\u53e5\u3002\u7531\u4e8e TRUNCATE TABLE \u4e0d\u8bb0\u5f55\u5728\u65e5\u5fd7\u4e2d\uff0c\u6240\u4ee5\u5b83\u4e0d\u80fd\u6fc0\u6d3b\u89e6\u53d1\u5668\u3002<\/p>\n

\u4e00\u3001delete<\/p>\n

1\u3001delete\u662fDML\uff0c\u6267\u884cdelete\u64cd\u4f5c\u65f6\uff0c\u6bcf\u6b21\u4ece\u8868\u4e2d\u5220\u9664\u4e00\u884c\uff0c\u5e76\u4e14\u540c\u65f6\u5c06\u8be5\u884c\u7684\u7684\u5220\u9664\u64cd\u4f5c\u8bb0\u5f55\u5728redo\u548cundo\u8868\u7a7a\u95f4\u4e2d\u4ee5\u4fbf\u8fdb\u884c\u56de\u6eda\uff08rollback\uff09\u548c\u91cd\u505a\u64cd\u4f5c\uff0c\u4f46\u8981\u6ce8\u610f\u8868\u7a7a\u95f4\u8981\u8db3\u591f\u5927\uff0c\u9700\u8981\u624b\u52a8\u63d0\u4ea4\uff08commit\uff09\u64cd\u4f5c\u624d\u80fd\u751f\u6548\uff0c\u53ef\u4ee5\u901a\u8fc7rollback\u64a4\u6d88\u64cd\u4f5c\u3002<\/p>\n

2\u3001delete\u53ef\u6839\u636e\u6761\u4ef6\u5220\u9664\u8868\u4e2d\u6ee1\u8db3\u6761\u4ef6\u7684\u6570\u636e\uff0c\u5982\u679c\u4e0d\u6307\u5b9awhere\u5b50\u53e5\uff0c\u90a3\u4e48\u5220\u9664\u8868\u4e2d\u6240\u6709\u8bb0\u5f55\u3002<\/p>\n

3\u3001delete\u8bed\u53e5\u4e0d\u5f71\u54cd\u8868\u6240\u5360\u7528\u7684extent\uff0c\u9ad8\u6c34\u7ebf(high watermark)\u4fdd\u6301\u539f\u4f4d\u7f6e\u4e0d\u53d8\u3002<\/p>\n

\u4e8c\u3001truncate<\/p>\n

1\u3001truncate\u662fDDL\uff0c\u4f1a\u9690\u5f0f\u63d0\u4ea4\uff0c\u6240\u4ee5\uff0c\u4e0d\u80fd\u56de\u6eda\uff0c\u4e0d\u4f1a\u89e6\u53d1\u89e6\u53d1\u5668\u3002<\/p>\n

2\u3001truncate\u4f1a\u5220\u9664\u8868\u4e2d\u6240\u6709\u8bb0\u5f55\uff0c\u5e76\u4e14\u5c06\u91cd\u65b0\u8bbe\u7f6e\u9ad8\u6c34\u7ebf\u548c\u6240\u6709\u7684\u7d22\u5f15\uff0c\u7f3a\u7701\u60c5\u51b5\u4e0b\u5c06\u7a7a\u95f4\u91ca\u653e\u5230minextents\u4e2aextent\uff0c\u9664\u975e\u4f7f\u7528reuse storage\uff0c\u3002\u4e0d\u4f1a\u8bb0\u5f55\u65e5\u5fd7\uff0c\u6240\u4ee5\u6267\u884c\u901f\u5ea6\u5f88\u5feb\uff0c\u4f46\u4e0d\u80fd\u901a\u8fc7rollback\u64a4\u6d88\u64cd\u4f5c\uff08\u5982\u679c\u4e00\u4e0d\u5c0f\u5fc3\u628a\u4e00\u4e2a\u8868truncate\u6389\uff0c\u4e5f\u662f\u53ef\u4ee5\u6062\u590d\u7684\uff0c\u53ea\u662f\u4e0d\u80fd\u901a\u8fc7rollback\u6765\u6062\u590d\uff09\u3002<\/p>\n

3\u3001\u5bf9\u4e8e\u5916\u952e\uff08foreignkey \uff09\u7ea6\u675f\u5f15\u7528\u7684\u8868\uff0c\u4e0d\u80fd\u4f7f\u7528 truncate table\uff0c\u800c\u5e94\u4f7f\u7528\u4e0d\u5e26 where \u5b50\u53e5\u7684 delete \u8bed\u53e5\u3002<\/p>\n

4\u3001truncatetable\u4e0d\u80fd\u7528\u4e8e\u53c2\u4e0e\u4e86\u7d22\u5f15\u89c6\u56fe\u7684\u8868\u3002<\/p>\n

\u4e09\u3001drop<\/p>\n

1\u3001drop\u662fDDL\uff0c\u4f1a\u9690\u5f0f\u63d0\u4ea4\uff0c\u6240\u4ee5\uff0c\u4e0d\u80fd\u56de\u6eda\uff0c\u4e0d\u4f1a\u89e6\u53d1\u89e6\u53d1\u5668\u3002<\/p>\n

2\u3001drop\u8bed\u53e5\u5220\u9664\u8868\u7ed3\u6784\u53ca\u6240\u6709\u6570\u636e\uff0c\u5e76\u5c06\u8868\u6240\u5360\u7528\u7684\u7a7a\u95f4\u5168\u90e8\u91ca\u653e\u3002<\/p>\n

3\u3001drop\u8bed\u53e5\u5c06\u5220\u9664\u8868\u7684\u7ed3\u6784\u6240\u4f9d\u8d56\u7684\u7ea6\u675f\uff0c\u89e6\u53d1\u5668\uff0c\u7d22\u5f15\uff0c\u4f9d\u8d56\u4e8e\u8be5\u8868\u7684\u5b58\u50a8\u8fc7\u7a0b\/\u51fd\u6570\u5c06\u4fdd\u7559,\u4f46\u662f\u53d8\u4e3ainvalid\u72b6\u6001\u3002<\/p>\n

 <\/p>\n

\u603b\u7ed3\uff1a<\/p>\n

1\u3001\u5728\u901f\u5ea6\u4e0a\uff0c\u4e00\u822c\u6765\u8bf4\uff0cdrop> truncate > delete\u3002<\/p>\n

2\u3001\u5728\u4f7f\u7528drop\u548ctruncate\u65f6\u4e00\u5b9a\u8981\u6ce8\u610f\uff0c\u867d\u7136\u53ef\u4ee5\u6062\u590d\uff0c\u4f46\u4e3a\u4e86\u51cf\u5c11\u9ebb\u70e6\uff0c\u8fd8\u662f\u8981\u614e\u91cd\u3002<\/p>\n

3\u3001\u5982\u679c\u60f3\u5220\u9664\u90e8\u5206\u6570\u636e\u7528delete\uff0c\u6ce8\u610f\u5e26\u4e0awhere\u5b50\u53e5\uff0c\u56de\u6eda\u6bb5\u8981\u8db3\u591f\u5927\uff1b<\/p>\n

   \u5982\u679c\u60f3\u5220\u9664\u8868\uff0c\u5f53\u7136\u7528drop\uff1b <\/p>\n

   \u5982\u679c\u60f3\u4fdd\u7559\u8868\u800c\u5c06\u6240\u6709\u6570\u636e\u5220\u9664\uff0c\u5982\u679c\u548c\u4e8b\u52a1\u65e0\u5173\uff0c\u7528truncate\u5373\u53ef\uff1b<\/p>\n

   \u5982\u679c\u548c\u4e8b\u52a1\u6709\u5173\uff0c\u6216\u8005\u60f3\u89e6\u53d1trigger\uff0c\u8fd8\u662f\u7528delete\uff1b<\/p>\n

   \u5982\u679c\u662f\u6574\u7406\u8868\u5185\u90e8\u7684\u788e\u7247\uff0c\u53ef\u4ee5\u7528truncate\u8ddf\u4e0areuse stroage\uff0c\u518d\u91cd\u65b0\u5bfc\u5165\/\u63d2\u5165\u6570\u636e\u3002<\/p>\n

\u897f\u6570\u79d1\u6280: \u53f8\u6cd5\u9274\u5b9a\/\u4ea7\u54c1\u8d28\u91cf\u9274\u5b9a\/\u68c0\u9a8c\u68c0\u6d4b\/\u6570\u636e\u6062\u590d\u4e13\u5bb6. 4006184118<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"

drop\u3001truncate\u548cdelete\u7684\u533a\u522b \uff081\uff09DELETE\u8bed\u53e5\u6267\u884c\u5220\u9664\u7684\u8fc7\u7a0b\u662f\u6bcf\u6b21\u4ece\u8868\u4e2d\u5220\u9664\u4e00\u884c\uff0c\u5e76\u4e14\u540c\u65f6\u5c06\u8be5\u884c\u7684\u5220\u9664\u64cd\u4f5c\u4f5c\u4e3a\u4e8b\u52a1\u8bb0\u5f55\u5728\u65e5\u5fd7\u4e2d\u4fdd\u5b58\u4ee5\u4fbf\u8fdb\u884c\u8fdb\u884c\u56de\u6eda\u64cd\u4f5c\u3002  &nbsp… <\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[297,294,293],"tags":[289,56,142,146,148],"class_list":["post-647","post","type-post","status-publish","format-standard","hentry","category-mobile-case","category-sabase-case","category-server-case","tag-it","tag-oracle","tag-142","tag-146","tag-148"],"_links":{"self":[{"href":"http:\/\/www.jointchina.com\/index.php\/wp-json\/wp\/v2\/posts\/647","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.jointchina.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.jointchina.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.jointchina.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.jointchina.com\/index.php\/wp-json\/wp\/v2\/comments?post=647"}],"version-history":[{"count":1,"href":"http:\/\/www.jointchina.com\/index.php\/wp-json\/wp\/v2\/posts\/647\/revisions"}],"predecessor-version":[{"id":8862,"href":"http:\/\/www.jointchina.com\/index.php\/wp-json\/wp\/v2\/posts\/647\/revisions\/8862"}],"wp:attachment":[{"href":"http:\/\/www.jointchina.com\/index.php\/wp-json\/wp\/v2\/media?parent=647"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.jointchina.com\/index.php\/wp-json\/wp\/v2\/categories?post=647"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.jointchina.com\/index.php\/wp-json\/wp\/v2\/tags?post=647"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}