{"id":60607,"date":"2024-10-13T04:16:15","date_gmt":"2024-10-12T20:16:15","guid":{"rendered":"https:\/\/server.hk\/cnblog\/60607\/"},"modified":"2024-10-13T04:16:15","modified_gmt":"2024-10-12T20:16:15","slug":"db2%e5%88%aa%e9%99%a4%e6%95%b8%e6%93%9a%e6%99%82%e7%9a%84%e5%b0%8f%e6%8a%80%e5%b7%a7","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/60607\/","title":{"rendered":"DB2\u522a\u9664\u6578\u64da\u6642\u7684\u5c0f\u6280\u5de7"},"content":{"rendered":"<h1 id=\"db2%e5%88%aa%e9%99%a4%e6%95%b8%e6%93%9a%e6%99%82%e7%9a%84%e5%b0%8f%e6%8a%80%e5%b7%a7-kVoLhMmAON\">DB2\u522a\u9664\u6578\u64da\u6642\u7684\u5c0f\u6280\u5de7<\/h1>\n<p>\u5728\u6578\u64da\u5eab\u7ba1\u7406\u4e2d\uff0c\u522a\u9664\u6578\u64da\u662f\u4e00\u9805\u5e38\u898b\u7684\u64cd\u4f5c\u3002\u5c0d\u65bc\u4f7f\u7528IBM DB2\u7684\u958b\u767c\u8005\u548c\u6578\u64da\u5eab\u7ba1\u7406\u54e1\u4f86\u8aaa\uff0c\u4e86\u89e3\u5982\u4f55\u6709\u6548\u5730\u522a\u9664\u6578\u64da\u4e0d\u50c5\u80fd\u63d0\u9ad8\u6027\u80fd\uff0c\u9084\u80fd\u907f\u514d\u4e0d\u5fc5\u8981\u7684\u6578\u64da\u640d\u5931\u3002\u672c\u6587\u5c07\u4ecb\u7d39\u4e00\u4e9b\u5728DB2\u4e2d\u522a\u9664\u6578\u64da\u6642\u7684\u5c0f\u6280\u5de7\uff0c\u5e6b\u52a9\u7528\u6236\u66f4\u9ad8\u6548\u5730\u7ba1\u7406\u6578\u64da\u3002<\/p>\n<h2 id=\"1-%e4%bd%bf%e7%94%a8where%e5%ad%90%e5%8f%a5%e7%b2%be%e7%a2%ba%e5%88%aa%e9%99%a4-kVoLhMmAON\">1. \u4f7f\u7528WHERE\u5b50\u53e5\u7cbe\u78ba\u522a\u9664<\/h2>\n<p>\u5728\u57f7\u884c\u522a\u9664\u64cd\u4f5c\u6642\uff0c\u4f7f\u7528<strong>WHERE<\/strong>\u5b50\u53e5\u662f\u81f3\u95dc\u91cd\u8981\u7684\u3002\u9019\u6a23\u53ef\u4ee5\u78ba\u4fdd\u53ea\u522a\u9664\u7b26\u5408\u7279\u5b9a\u689d\u4ef6\u7684\u6578\u64da\uff0c\u907f\u514d\u610f\u5916\u522a\u9664\u6574\u500b\u8868\u4e2d\u7684\u6578\u64da\u3002<\/p>\n<pre><code>DELETE FROM \u8868\u540d WHERE \u689d\u4ef6;<\/code><\/pre>\n<p>\u4f8b\u5982\uff0c\u5982\u679c\u8981\u522a\u9664\u67d0\u500b\u7528\u6236\u7684\u6578\u64da\uff0c\u53ef\u4ee5\u9019\u6a23\u5beb\uff1a<\/p>\n<pre><code>DELETE FROM users WHERE user_id = 123;<\/code><\/pre>\n<h2 id=\"2-%e4%bd%bf%e7%94%a8limit%e9%99%90%e5%88%b6%e5%88%aa%e9%99%a4%e6%95%b8%e9%87%8f-kVoLhMmAON\">2. \u4f7f\u7528LIMIT\u9650\u5236\u522a\u9664\u6578\u91cf<\/h2>\n<p>\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\uff0c\u60a8\u53ef\u80fd\u5e0c\u671b\u4e00\u6b21\u522a\u9664\u5c11\u91cf\u6578\u64da\u3002DB2\u652f\u6301\u4f7f\u7528<strong>FETCH FIRST<\/strong>\u4f86\u9650\u5236\u522a\u9664\u7684\u884c\u6578\u3002\u9019\u5728\u8655\u7406\u5927\u91cf\u6578\u64da\u6642\u7279\u5225\u6709\u7528\uff0c\u53ef\u4ee5\u6e1b\u5c11\u5c0d\u7cfb\u7d71\u6027\u80fd\u7684\u5f71\u97ff\u3002<\/p>\n<pre><code>DELETE FROM \u8868\u540d WHERE \u689d\u4ef6 FETCH FIRST 10 ROWS ONLY;<\/code><\/pre>\n<h2 id=\"3-%e4%ba%8b%e5%8b%99%e7%ae%a1%e7%90%86-kVoLhMmAON\">3. \u4e8b\u52d9\u7ba1\u7406<\/h2>\n<p>\u5728\u522a\u9664\u6578\u64da\u6642\uff0c\u4f7f\u7528\u4e8b\u52d9\u7ba1\u7406\u53ef\u4ee5\u78ba\u4fdd\u6578\u64da\u7684\u4e00\u81f4\u6027\u548c\u5b8c\u6574\u6027\u3002\u901a\u904e\u4f7f\u7528<strong>BEGIN<\/strong>\u548c<strong>COMMIT<\/strong>\u8a9e\u53e5\uff0c\u60a8\u53ef\u4ee5\u5728\u522a\u9664\u64cd\u4f5c\u4e2d\u9032\u884c\u56de\u6efe\uff0c\u5f9e\u800c\u907f\u514d\u610f\u5916\u522a\u9664\u3002<\/p>\n<pre><code>BEGIN;\nDELETE FROM \u8868\u540d WHERE \u689d\u4ef6;\nCOMMIT;<\/code><\/pre>\n<p>\u5982\u679c\u5728\u522a\u9664\u904e\u7a0b\u4e2d\u767c\u751f\u932f\u8aa4\uff0c\u53ef\u4ee5\u4f7f\u7528<strong>ROLLBACK<\/strong>\u4f86\u64a4\u92b7\u64cd\u4f5c\uff1a<\/p>\n<pre><code>ROLLBACK;<\/code><\/pre>\n<h2 id=\"4-%e4%bd%bf%e7%94%a8%e6%a8%99%e8%a8%98%e5%88%aa%e9%99%a4-kVoLhMmAON\">4. \u4f7f\u7528\u6a19\u8a18\u522a\u9664<\/h2>\n<p>\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\uff0c\u60a8\u53ef\u80fd\u4e0d\u5e0c\u671b\u7acb\u5373\u522a\u9664\u6578\u64da\uff0c\u800c\u662f\u5e0c\u671b\u5c07\u5176\u6a19\u8a18\u70ba\u522a\u9664\u3002\u9019\u6a23\u53ef\u4ee5\u4fdd\u7559\u6578\u64da\u4ee5\u4fbf\u5c07\u4f86\u67e5\u8a62\u6216\u6062\u5fa9\u3002\u60a8\u53ef\u4ee5\u5728\u8868\u4e2d\u6dfb\u52a0\u4e00\u500b\u6a19\u8a18\u6b04\u4f4d\uff0c\u4f8b\u5982<strong>is_deleted<\/strong>\uff0c\u7136\u5f8c\u901a\u904e\u66f4\u65b0\u64cd\u4f5c\u4f86\u6a19\u8a18\u6578\u64da\u3002<\/p>\n<pre><code>UPDATE \u8868\u540d SET is_deleted = 1 WHERE \u689d\u4ef6;<\/code><\/pre>\n<h2 id=\"5-%e5%ae%9a%e6%9c%9f%e6%b8%85%e7%90%86%e6%95%b8%e6%93%9a-kVoLhMmAON\">5. \u5b9a\u671f\u6e05\u7406\u6578\u64da<\/h2>\n<p>\u5b9a\u671f\u6e05\u7406\u4e0d\u518d\u9700\u8981\u7684\u6578\u64da\u53ef\u4ee5\u63d0\u9ad8\u6578\u64da\u5eab\u7684\u6027\u80fd\u3002\u60a8\u53ef\u4ee5\u8a2d\u7f6e\u5b9a\u671f\u4efb\u52d9\uff0c\u81ea\u52d5\u522a\u9664\u904e\u671f\u6216\u4e0d\u518d\u9700\u8981\u7684\u6578\u64da\u3002\u4f8b\u5982\uff0c\u60a8\u53ef\u4ee5\u6bcf\u6708\u522a\u9664\u4e00\u5e74\u524d\u7684\u6578\u64da\uff1a<\/p>\n<pre><code>DELETE FROM \u8868\u540d WHERE created_at &lt; CURRENT DATE - 365 DAYS;<\/code><\/pre>\n<h2 id=\"6-%e4%bd%bf%e7%94%a8db2%e7%9a%84%e6%80%a7%e8%83%bd%e5%84%aa%e5%8c%96%e5%b7%a5%e5%85%b7-kVoLhMmAON\">6. \u4f7f\u7528DB2\u7684\u6027\u80fd\u512a\u5316\u5de5\u5177<\/h2>\n<p>DB2\u63d0\u4f9b\u4e86\u4e00\u4e9b\u6027\u80fd\u512a\u5316\u5de5\u5177\uff0c\u53ef\u4ee5\u5e6b\u52a9\u7528\u6236\u5206\u6790\u548c\u512a\u5316\u522a\u9664\u64cd\u4f5c\u3002\u4f7f\u7528<strong>EXPLAIN<\/strong>\u8a9e\u53e5\u53ef\u4ee5\u67e5\u770b\u522a\u9664\u64cd\u4f5c\u7684\u57f7\u884c\u8a08\u5283\uff0c\u5f9e\u800c\u627e\u51fa\u6f5b\u5728\u7684\u6027\u80fd\u74f6\u9838\u3002<\/p>\n<pre><code>EXPLAIN DELETE FROM \u8868\u540d WHERE \u689d\u4ef6;<\/code><\/pre>\n<h2 id=\"%e7%b8%bd%e7%b5%90-kVoLhMmAON\">\u7e3d\u7d50<\/h2>\n<p>\u5728DB2\u4e2d\u522a\u9664\u6578\u64da\u6642\uff0c\u9075\u5faa\u4e0a\u8ff0\u5c0f\u6280\u5de7\u53ef\u4ee5\u5e6b\u52a9\u7528\u6236\u66f4\u9ad8\u6548\u5730\u7ba1\u7406\u6578\u64da\uff0c\u6e1b\u5c11\u932f\u8aa4\u548c\u6027\u80fd\u554f\u984c\u3002\u7121\u8ad6\u662f\u4f7f\u7528<strong>WHERE<\/strong>\u5b50\u53e5\u7cbe\u78ba\u522a\u9664\uff0c\u9084\u662f\u5229\u7528\u4e8b\u52d9\u7ba1\u7406\u78ba\u4fdd\u6578\u64da\u4e00\u81f4\u6027\uff0c\u9019\u4e9b\u65b9\u6cd5\u90fd\u80fd\u63d0\u5347\u6578\u64da\u5eab\u7684\u904b\u884c\u6548\u7387\u3002\u5c0d\u65bc\u9700\u8981\u9ad8\u6548\u6578\u64da\u7ba1\u7406\u7684\u7528\u6236\uff0c\u9078\u64c7\u5408\u9069\u7684<a href=\"https:\/\/server.hk\">VPS<\/a>\u89e3\u6c7a\u65b9\u6848\u4e5f\u662f\u81f3\u95dc\u91cd\u8981\u7684\uff0c\u9019\u6a23\u53ef\u4ee5\u78ba\u4fdd\u6578\u64da\u5eab\u7684\u7a69\u5b9a\u6027\u548c\u5b89\u5168\u6027\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u638c\u63e1DB2\u522a\u9664\u6578\u64da\u7684\u5c0f\u6280\u5de7\uff0c\u63d0\u5347\u6578\u64da\u7ba1\u7406\u6548\u7387\uff0c\u907f\u514d\u4e0d\u5fc5\u8981\u7684\u932f\u8aa4\uff0c\u78ba\u4fdd\u6578\u64da\u5b89\u5168\u8207\u5b8c\u6574\u6027\u3002<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-60607","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/60607","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"}],"author":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=60607"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/60607\/revisions"}],"predecessor-version":[{"id":60608,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/60607\/revisions\/60608"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=60607"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=60607"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=60607"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}