{"id":1224,"date":"2015-05-03T23:46:35","date_gmt":"2015-05-03T15:46:35","guid":{"rendered":"http:\/\/coderbee.net\/?p=1224"},"modified":"2019-01-06T21:22:07","modified_gmt":"2019-01-06T13:22:07","slug":"oracle-b-tree-%e7%b4%a2%e5%bc%95%e7%9a%84%e7%bb%93%e6%9e%84%e3%80%81%e7%89%b9%e7%82%b9%e5%8f%8a%e7%b4%a2%e5%bc%95%e6%89%ab%e6%8f%8f%e6%96%b9%e5%bc%8f","status":"publish","type":"post","link":"https:\/\/coderbee.net\/index.php\/db\/20150503\/1224","title":{"rendered":"Oracle B-Tree \u7d22\u5f15\u7684\u7ed3\u6784\u3001\u7279\u70b9\u53ca\u7d22\u5f15\u626b\u63cf\u65b9\u5f0f"},"content":{"rendered":"<p>\u300aOracle DBA \u624b\u8bb0 &#8212; \u6570\u636e\u5e93\u8bca\u65ad\u6848\u4f8b\u4e0e\u6027\u80fd\u4f18\u5316\u5b9e\u8df5\u300b\u6458\u5f55\uff08P218\uff09<\/p>\n<p>Oracle \u6570\u636e\u5e93\u4e2d\u7d22\u5f15\u7684\u5b58\u50a8\u7ed3\u6784\u4f7f\u7528\u7684\u662f B Tree \u7684\u4e00\u79cd\u53d8\u4f53\uff0c\u79f0\u4e3a B*Tree \uff08B Star Tree\uff09\uff0c\u5728\u6570\u636e\u5e93\u4e2d\u5b58\u50a8\u6570\u636e\u4ee5\u5757\u4e3a\u5355\u4f4d\u3002<br \/>\n<img decoding=\"async\" src=\"http:\/\/coderbee.net\/wp-content\/uploads\/2015\/05\/Oracle-B-Tree\u7d22\u5f15\u7ed3\u6784.jpg\" alt=\"Oracle B-Tree\u7d22\u5f15\u7ed3\u6784\" \/><\/p>\n<p>\u4e00\u4e9b\u672f\u8bed\uff1a<\/p>\n<ul>\n<li>\u8282\u70b9 M \u7684\u6df1\u5ea6\uff1a\u4ece\u6811\u6839\u8282\u70b9\u5230\u8282\u70b9 M \u7684\u6700\u77ed\u8def\u5f84\u957f\u5ea6\u3002\u56fe\u4e2d\u6839\u8282\u70b9 Root \u7684\u6df1\u5ea6\u662f 0\uff0c\u8282\u70b9 L1-1 \u7684\u6df1\u5ea6\u662f 1\uff0c\u8282\u70b9 L0-1 \u7684\u6df1\u5ea6\u662f 2\u3002<\/li>\n<li>\u8282\u70b9 M \u7684\u5c42\u6570\uff1a\u8282\u70b9 M \u7684\u5c42\u6570\u4e0e\u5176\u6df1\u5ea6\u662f\u76f8\u540c\u7684\u3002<\/li>\n<li>\u6811\u7684\u9ad8\u5ea6\uff1a\u6811\u7684\u6df1\u5ea6\u503c\u6700\u5927\u7684\u90a3\u4e2a\u8282\u70b9\uff0c\u5176\u6df1\u5ea6 <code>+1<\/code> \u5373\u4e3a\u6811\u7684\u9ad8\u5ea6\u3002\u56fe\u4e2d\u6811\u7684\u9ad8\u5ea6\u4e3a 3\u3002<\/li>\n<\/ul>\n<p><!--more--><\/p>\n<p>Oracle \u6570\u636e\u5e93\u7684\u7d22\u5f15\u6709\u4e0b\u5217\u7684\u7279\u70b9\uff1a<\/p>\n<ul>\n<li>\n<p>\u5b58\u50a8\u7d22\u5f15\u6570\u636e\u7684\u5757\uff0c\u79f0\u4e3a B Tree \u7684\u8282\u70b9\u3002\u6709\u4e09\u79cd\u7c7b\u578b\u7684\u8282\u70b9\uff0c\u6839\uff08root\uff09\u8282\u70b9\u3001\u5206\u652f\uff08branch\uff09\u8282\u70b9\u548c\u53f6\uff08leaf\uff09\u8282\u70b9\u3002\u9ad8\u5ea6\u4e3a 1 \u7684\u7d22\u5f15\u53ea\u6709\u6839\u8282\u70b9\uff0c\u8fd9\u65f6\u7d22\u5f15\u53ea\u6709\u552f\u4e00\u7684\u53f6\u8282\u70b9\uff0c\u4e5f\u540c\u65f6\u662f\u6839\u8282\u70b9\uff1b\u9ad8\u5ea6\u5927\u4e8e 1 \u65f6\uff0c\u6839\u8282\u70b9\u4e0e\u5206\u652f\u8282\u70b9\u5177\u6709\u5b8c\u5168\u76f8\u540c\u7684\u7ed3\u6784\uff0c\u4e5f\u5c31\u662f\u8bf4\u8fd9\u65f6\uff0c\u6839\u8282\u70b9\u4e5f\u662f\u5206\u652f\u8282\u70b9\u3002\u5206\u652f\u8282\u70b9\u7d22\u5f15\u5757\u5b58\u50a8\u7684\u6570\u636e\u4e3b\u8981\u5305\u62ec\uff1a\u7d22\u5f15\u503c\u3001\u952e\u503c\u5bf9\u5e94\u7684\u4e0b\u4e00\u7ea7\u8282\u70b9\u5757\u5730\u5740\u3001\u8fd8\u6709\u4e00\u4e2a\u79f0\u4e3a\u201ckdxbrlmc\u201d \u7684\u6307\u9488\uff0c\u4e5f\u5c31\u662f\u56fe\u4e2d\u7684 \u201clmc\u201d\uff0c\u8fd9\u4e2a\u6307\u9488\u5c31\u662f\u5f53\u524d\u679d\u8282\u70b9\u4e2d\u6700\u5c0f\u7684\u7d22\u5f15\u503c\u8fd8\u5c0f\u7684\u4e0b\u4e00\u7ea7\u8282\u70b9\u5757\u7684\u6570\u636e\u5757\u5730\u5740\uff08DBA\uff09\u3002\u53f6\u8282\u70b9\u7d22\u5f15\u5757\u5b58\u50a8\u7684\u6570\u636e\u4e3b\u8981\u662f\u7d22\u5f15\u503c\u4ee5\u53ca\u5bf9\u5e94\u7684 rowid\uff0c\u548c\u5f53\u524d\u8282\u70b9\u7684\u524d\u540e\u4e24\u4e2a\u8282\u70b9\u7684\u6570\u636e\u5757\u5730\u5740\u3002<\/p>\n<\/li>\n<li>\n<p>\u7d22\u5f15\u7684\u6839\u8282\u70b9\uff0c\u603b\u662f\u7d27\u8ddf\u5728\u7d22\u5f15\u6bb5\u5934\u7684\u540e\u9762\u7684\u4e00\u4e2a\u6570\u636e\u5757\u3002\u6bd4\u5982\u67d0\u4e2a\u7d22\u5f15\u7684\u6bb5\u5934\u4e3a <code>7\/817<\/code>\uff08\u76f8\u5bf9\u6587\u4ef6\u53f7\/\u5757\u53f7\uff09\uff0c\u90a3\u4e48\u6839\u8282\u70b9\u5c31\u662f <code>7\/7818<\/code>\u3002Oracle \u5728\u6267\u884c SQL \u65f6\uff0c\u76f4\u63a5\u4ece\u6570\u636e\u5b57\u5178\u5f97\u5230\u6bb5\u5934\u4f4d\u7f6e\u540e\u5c31\u80fd\u5b9a\u4f4d\u5230\u6839\u8282\u70b9\u3002\u8fd9\u53ef\u4ee5\u51cf\u5c11\u903b\u8f91\u8bfb\u3002<\/p>\n<\/li>\n<li>\n<p>\u7d22\u5f15\u662f\u59cb\u7ec8\u5e73\u8861\u7684\u3002<\/p>\n<\/li>\n<li>\n<p>\u7d22\u5f15\u7684\u6bcf\u4e00\u4e2a\u53f6\u8282\u70b9\uff0c\u6709\u4e24\u4e2a\u6307\u9488\uff0c\u5206\u522b\u6307\u5411\u6bd4\u5f53\u524d\u8282\u70b9\u6700\u5c0f\u7d22\u5f15\u503c\u8fd8\u5c0f\u7684\u53f6\u8282\u70b9\u5757\u7684\u5730\u5740\uff0c\u4ee5\u53ca\u6bd4\u5f53\u524d\u8282\u70b9\u6700\u5927\u7d22\u5f15\u503c\u8fd8\u5927\u7684\u53f6\u8282\u70b9\u5757\u5730\u5740\u3002\u901a\u8fc7\u8fd9\u4e24\u4e2a\u6307\u9488\uff0c\u628a\u6240\u6709\u7684\u53f6\u8282\u70b9\u4e32\u8d77\u6765\uff0c\u5f62\u6210\u4e00\u4e2a\u53cc\u5411\u94fe\u8868\u3002\u987a\u5e8f\u904d\u5386\u8fd9\u4e2a\u94fe\u8868\u5373\u53ef\u5f97\u5230\u6709\u5e8f\u7684\u6570\u636e\u3002<\/p>\n<\/li>\n<li>\n<p>\u7d22\u5f15\u7684\u5206\u679d\u8282\u70b9\u5757\u6240\u5b58\u50a8\u7684\u7d22\u5f15\u503c\uff0c\u5e76\u4e0d\u662f\u5b8c\u6574\u7684\u7d22\u5f15\u503c\uff0c\u800c\u53ea\u662f\u6574\u4e2a\u7d22\u5f15\u503c\u7684\u524d\u7f00\uff0c\u53ea\u8981\u80fd\u591f\u533a\u5206\u5176\u5927\u5c0f\u5c31\u53ef\u4ee5\u3002\u6bd4\u5982\u56fe\u4e2d L1-1 \u5206\u679d\u8282\u70b9\uff0c\u6709\u4e24\u4e2a\u503c\uff0c AD \u548c AK\uff0c\u5176\u6307\u5411\u7684\u53f6\u8282\u70b9\u8d77\u59cb\u7d22\u5f15\u503c\u4e3a ADK \u4ee5\u53ca AKA\uff0c\u4f46\u662f\u5176\u524d\u7f00 AD \u548c AK \u5373\u53ef\u4ee5\u533a\u5206\u5176\u5927\u5c0f\u3002\u8fd9\u79cd\u8bbe\u8ba1\u80fd\u591f\u4f7f\u5206\u679d\u8282\u70b9\u5b58\u50a8\u66f4\u591a\u7684\u6761\u76ee\uff0c\u51cf\u5c11\u4e86\u5206\u679d\u8282\u70b9\u6570\uff0c\u7279\u522b\u662f\u5728\u591a\u5217\u590d\u5408\u7d22\u5f15\u4e2d\uff0c\u5bf9\u4e8e\u5f88\u5927\u7684\u8868\uff0c\u751a\u81f3\u53ef\u4ee5\u51cf\u5c11 B Tree \u7684\u9ad8\u5ea6\u3002<\/p>\n<\/li>\n<li>\n<p>B Tree \u7d22\u5f15\u4e0d\u5bf9 NULL \u503c\u8fdb\u884c\u7d22\u5f15\uff0c\u5bf9\u4e8e\u67d0\u4e00\u5217\uff0c\u7d22\u5f15\u7684\u6240\u6709\u5217\u7684\u503c\u90fd\u662f NULL \u503c\u65f6\uff0c\u8be5\u884c\u4e0d\u80fd\u88ab\u7d22\u5f15\u3002\u590d\u5408\u7d22\u5f15\u53ea\u8981\u6709\u4e00\u5217\u4e0d\u4e3a NULL \u662f\u53ef\u4ee5\u88ab\u7d22\u5f15\u7684\u3002<\/p>\n<\/li>\n<\/ul>\n<h3>Oracle \u5982\u4f55\u626b\u63cf\u7d22\u5f15<\/h3>\n<p>Oracle \u5728\u626b\u63cf B Tree \u7d22\u5f15\u65f6\u53ef\u4ee5\u4ece\u7d22\u5f15\u7684\u5de6\u7aef\u626b\u63cf\u5230\u53f3\u7aef\u6216\u8005\u4ece\u53f3\u7aef\u626b\u63cf\u5230\u5de6\u7aef\u3002\u5bf9\u4e8e\u7d22\u5f15\u552f\u4e00\u626b\u63cf\uff0c\u4e24\u8005\u6ca1\u5565\u533a\u522b\uff0c\u4e24\u8005\u7684\u533a\u522b\u4e3b\u8981\u4f53\u73b0\u5728\u7d22\u5f15\u8303\u56f4\u626b\u63cf\uff0c\u5305\u62ec\u7d22\u5f15\u8df3\u8dc3\u626b\u63cf\uff08INDEX SKIP SCAN\uff09\u548c\u7d22\u5f15\u5168\u626b\u63cf\uff08INDEX FULL SCAN\uff09\u3002<\/p>\n<p>\u4e00\u822c\u60c5\u51b5\u4e0b\uff0c\u7d22\u5f15\u90fd\u662f\u4ece\u5de6\u7aef\u626b\u63cf\u5230\u53f3\u7aef\uff0c\u53ea\u6709\u5728\u4f7f\u7528\u4e86\u5982 <code>INDEX_DESC<\/code> \u8fd9\u6837\u7684 HINT \u6216\u4f7f\u7528 <code>ORDER BY DESC<\/code> \uff08\u5982\u679c\u662f\u964d\u5e8f\u7d22\u5f15\uff0c\u5219\u662f <code>ORDER BY<\/code>\uff09\u65f6\u624d\u4f1a\u4ece\u53f3\u7aef\u626b\u63cf\u5230\u5de6\u7aef\u3002<\/p>\n<p>Oracle \u5728\u626b\u63cf\u7d22\u5f15\u65f6\uff0c\u9996\u5148\u4ece\u6570\u636e\u5b57\u5178\u5f97\u5230\u7d22\u5f15\u6bb5\u5934\u5757\u7684\u4f4d\u7f6e\uff0c\u8fd9\u4e2a\u5757\u5730\u5740 <code>+1<\/code> \u5373\u5f97\u5230\u7d22\u5f15\u7684 root block \u5757\u5730\u5740\u3002\u901a\u8fc7 root block \u5b9a\u4f4d\u5230 branch block\uff0c\u518d\u901a\u8fc7 branch block \u5b9a\u4f4d\u5230\u4e0b\u4e00\u7ea7 branch block\uff0c\u76f4\u81f3\u6700\u540e\u5b9a\u4f4d\u5230 leaf block\u3002\u7136\u540e\u4ece\u5b9a\u4f4d\u5230\u7684 leaf block \u6839\u636e\u786e\u5b9a\u7684\u626b\u63cf\u65b9\u5411\uff0c\u4ece\u5de6\u5f80\u53f3\u626b\u63cf\u6216\u4ece\u53f3\u5f80\u5de6\u626b\u63cf\u3002<\/p>\n<p>\u5728\u4ece\u7d22\u5f15\u4e2d\u626b\u63cf\u5230\u6570\u636e\uff0c\u5305\u62ec rowid \u4e4b\u540e\uff0c\u5982\u679c\u6240\u83b7\u5f97\u7684\u6570\u636e\u5df2\u7ecf\u6ee1\u8db3\u9700\u8981\uff0c\u5219\u5c06\u6570\u636e\u8fd4\u56de\u7ed9\u4e0a\u4e00\u6b65\uff0c\u6bd4\u5982\u76f4\u63a5\u8fd4\u56de\u7ed9\u5ba2\u6237\u7aef\uff0c\u5426\u5219\u5fc5\u987b\u6839\u636e rowid \uff0c\u518d\u4ece\u8868\u91cc\u83b7\u5f97\u6570\u636e\u8fd4\u56de\u7ed9\u4e0a\u4e00\u6b65\u3002<\/p>\n<p>\u5e38\u89c1\u7684\u51e0\u79cd\u7d22\u5f15\u626b\u63cf\u65b9\u5f0f\uff1a<\/p>\n<ul>\n<li>INDEX UNIQUE SCAN\uff1a\u7d22\u5f15\u552f\u4e00\u626b\u63cf\uff0c\u51fa\u73b0\u5728\u7d22\u5f15\u7684\u201c\u6240\u6709\u5217\u201d\u4e0a\u4f7f\u7528\u201c\u7b49\u4e8e\u201d\u6761\u4ef6\u7684 SQL \u4e2d\uff0c\u6700\u591a\u8fd4\u56de\u4e00\u884c\u7ed3\u679c\u3002<\/li>\n<li>INDEX RANGE SCAN\uff1a\u7d22\u5f15\u8303\u56f4\u626b\u63cf\uff0c\u51fa\u73b0\u5728\u975e\u552f\u4e00\u7d22\u5f15\u7684\u524d\u7f00\u6216\u6240\u6709\u5217\u4e0a\u4f7f\u7528\u4efb\u610f\u6bd4\u8f83\u6761\u4ef6\u7684 SQL \u4e2d\u3002<\/li>\n<li>INDEX FULL SCAN\uff1a\u7d22\u5f15\u5168\u626b\u63cf\uff0c\u6309\u987a\u5e8f\u626b\u63cf\u7d22\u5f15\u4e2d\u7684\u6240\u6709\u53f6\u8282\u70b9\u5757\u3002<\/li>\n<li>INDEX FAST FULL SCAN\uff1a\u7d22\u5f15\u5feb\u901f\u5168\u626b\u63cf\uff0c\u5e76\u884c\u8bfb\u53d6\u591a\u4e2a\u6570\u636e\u5757\u8fdb\u884c\u626b\u63cf\uff0c\u626b\u63cf\u5f97\u5230\u7684\u7ed3\u679c\u662f\u65e0\u5e8f\u7684\u3002<\/li>\n<li>INDEX SKIP SCAN\uff1a\u7d22\u5f15\u8df3\u8dc3\u626b\u63cf\uff0c\u51fa\u73b0\u5728\u590d\u5408\u7d22\u5f15\u4e2d\uff0c\u5bf9\u975e\u524d\u7f00\u5217\u4e0a\u4f7f\u7528\u4efb\u610f\u6bd4\u8f83\u6761\u4ef6\u7684 SQL \u4e2d\u3002Oracle \u5728\u626b\u63cf\u65f6\uff0c\u4f1a\u626b\u63cf\u6240\u6709\u7684 branch block\uff0c\u7136\u540e\u5bf9 branch block \u4e2d\u7684\u6bcf\u4e00\u4e2a\u503c\uff0c\u90fd\u4f1a\u53bb\u626b\u63cf leaf block\u3002\u9002\u5408\u4e8e\u590d\u5408\u7d22\u5f15\u7684\u524d\u7f00\u5217\u4e0d\u540c\u503c\u4e2a\u6570\u5f88\u5c11\u7684\u60c5\u51b5\uff0c\u5426\u5219\u5176\u626b\u63cf\u6210\u672c\u975e\u5e38\u9ad8\u3002<\/li>\n<\/ul>\n<p>\u9664\u4e86\u7b2c\u56db\u79cd\u90fd\u662f\u5bf9\u7d22\u5f15\u8fdb\u884c\u5355\u5757\u8bfb\uff0c\u7b2c\u56db\u79cd\u662f\u8fdb\u884c\u591a\u5757\u8bfb\u3002\u524d\u4e09\u79cd\u626b\u63cf\u65b9\u5f0f\uff0c\u5176\u7ed3\u679c\u662f\u6309\u503c\u7684\u5927\u5c0f\u987a\u5e8f\u8fd4\u56de\u7684\uff0c\u56e0\u6b64\u5728\u9700\u8981\u987a\u5e8f\u7ed3\u679c\uff08\u6bd4\u5982 ORDER BY\uff09\u65f6\uff0c\u80fd\u591f\u907f\u514d\u5728\u8fd9\u4e9b\u5217\u4e0a\u8fdb\u884c\u6392\u5e8f\u3002<\/p>\n<hr\/>\n<p>\u6b22\u8fce\u5173\u6ce8\u6211\u7684\u5fae\u4fe1\u516c\u4f17\u53f7: <strong>coderbee\u7b14\u8bb0<\/strong>\uff0c\u53ef\u4ee5\u66f4\u53ca\u65f6\u56de\u590d\u4f60\u7684\u8ba8\u8bba\u3002<br \/>\n<img loading=\"lazy\" decoding=\"async\" width=\"258\" height=\"258\" src=\"https:\/\/coderbee.net\/wp-content\/uploads\/2019\/01\/coderbee-note.jpg\" class=\"alignnone size-full wp-image-1707\"><\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u300aOracle DBA \u624b\u8bb0 &#8212; \u6570\u636e\u5e93\u8bca\u65ad\u6848\u4f8b\u4e0e\u6027\u80fd\u4f18\u5316\u5b9e\u8df5\u300b\u6458\u5f55 &hellip; <a href=\"https:\/\/coderbee.net\/index.php\/db\/20150503\/1224\">\u7ee7\u7eed\u9605\u8bfb <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[23],"tags":[99,215,217],"_links":{"self":[{"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/posts\/1224"}],"collection":[{"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/comments?post=1224"}],"version-history":[{"count":3,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/posts\/1224\/revisions"}],"predecessor-version":[{"id":1749,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/posts\/1224\/revisions\/1749"}],"wp:attachment":[{"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/media?parent=1224"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/categories?post=1224"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/tags?post=1224"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}