{"id":60501,"date":"2024-10-13T03:23:15","date_gmt":"2024-10-12T19:23:15","guid":{"rendered":"https:\/\/server.hk\/cnblog\/60501\/"},"modified":"2024-10-13T03:23:15","modified_gmt":"2024-10-12T19:23:15","slug":"db2%e9%9a%94%e9%9b%a2%e7%b4%9a%e5%88%a5-%e7%82%ba%e8%90%bd%e5%af%a6%e7%9a%84%e8%ae%80","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/60501\/","title":{"rendered":"DB2\u9694\u96e2\u7d1a\u5225&#8211;\u70ba\u843d\u5be6\u7684\u8b80"},"content":{"rendered":"<h1 id=\"db2%e9%9a%94%e9%9b%a2%e7%b4%9a%e5%88%a5-%e7%82%ba%e8%90%bd%e5%af%a6%e7%9a%84%e8%ae%80-ySGINFwkKd\">DB2\u9694\u96e2\u7d1a\u5225&#8211;\u70ba\u843d\u5be6\u7684\u8b80<\/h1>\n<p>\u5728\u8cc7\u6599\u5eab\u7ba1\u7406\u7cfb\u7d71\u4e2d\uff0c\u9694\u96e2\u7d1a\u5225\u662f\u78ba\u4fdd\u8cc7\u6599\u4e00\u81f4\u6027\u548c\u5b8c\u6574\u6027\u7684\u91cd\u8981\u6a5f\u5236\u3002IBM\u7684DB2\u8cc7\u6599\u5eab\u7cfb\u7d71\u63d0\u4f9b\u4e86\u591a\u7a2e\u9694\u96e2\u7d1a\u5225\uff0c\u4ee5\u6eff\u8db3\u4e0d\u540c\u61c9\u7528\u5834\u666f\u7684\u9700\u6c42\u3002\u672c\u6587\u5c07\u6df1\u5165\u63a2\u8a0eDB2\u7684\u9694\u96e2\u7d1a\u5225\uff0c\u7279\u5225\u662f\u300c\u70ba\u843d\u5be6\u7684\u8b80\u300d\uff08Read Committed\uff09\u9694\u96e2\u7d1a\u5225\u7684\u7279\u9ede\u53ca\u5176\u61c9\u7528\u3002<\/p>\n<h2 id=\"%e4%bb%80%e9%ba%bc%e6%98%af%e9%9a%94%e9%9b%a2%e7%b4%9a%e5%88%a5%ef%bc%9f-ySGINFwkKd\">\u4ec0\u9ebc\u662f\u9694\u96e2\u7d1a\u5225\uff1f<\/h2>\n<p>\u9694\u96e2\u7d1a\u5225\u5b9a\u7fa9\u4e86\u591a\u500b\u4ea4\u6613\u4e4b\u9593\u7684\u76f8\u4e92\u5f71\u97ff\u7a0b\u5ea6\u3002\u6839\u64da\u4e0d\u540c\u7684\u9694\u96e2\u7d1a\u5225\uff0c\u4ea4\u6613\u53ef\u4ee5\u770b\u5230\u5176\u4ed6\u4ea4\u6613\u7684\u8b8a\u66f4\uff0c\u9019\u6703\u5f71\u97ff\u5230\u8cc7\u6599\u7684\u4e00\u81f4\u6027\u3002DB2\u652f\u6301\u4ee5\u4e0b\u5e7e\u7a2e\u4e3b\u8981\u7684\u9694\u96e2\u7d1a\u5225\uff1a<\/p>\n<ul>\n<li>\u8b80\u53d6\u672a\u63d0\u4ea4\uff08Read Uncommitted\uff09<\/li>\n<li>\u8b80\u53d6\u5df2\u63d0\u4ea4\uff08Read Committed\uff09<\/li>\n<li>\u53ef\u91cd\u8907\u8b80\u53d6\uff08Repeatable Read\uff09<\/li>\n<li>\u5e8f\u5217\u5316\uff08Serializable\uff09<\/li>\n<\/ul>\n<h2 id=\"%e7%82%ba%e8%90%bd%e5%af%a6%e7%9a%84%e8%ae%80%ef%bc%88read-committed%ef%bc%89-ySGINFwkKd\">\u70ba\u843d\u5be6\u7684\u8b80\uff08Read Committed\uff09<\/h2>\n<p>\u300c\u70ba\u843d\u5be6\u7684\u8b80\u300d\u662fDB2\u4e2d\u6700\u5e38\u7528\u7684\u9694\u96e2\u7d1a\u5225\u4e4b\u4e00\u3002\u5728\u9019\u500b\u7d1a\u5225\u4e0b\uff0c\u4ea4\u6613\u53ea\u80fd\u8b80\u53d6\u5df2\u63d0\u4ea4\u7684\u8cc7\u6599\uff0c\u9019\u610f\u5473\u8457\u5728\u4e00\u500b\u4ea4\u6613\u4e2d\uff0c\u672a\u63d0\u4ea4\u7684\u8b8a\u66f4\u5c0d\u5176\u4ed6\u4ea4\u6613\u662f\u4e0d\u53ef\u898b\u7684\u3002\u9019\u6a23\u7684\u8a2d\u8a08\u53ef\u4ee5\u6709\u6548\u907f\u514d\u300c\u9ad2\u8b80\u300d\uff08Dirty Read\uff09\u554f\u984c\uff0c\u5373\u4e00\u500b\u4ea4\u6613\u8b80\u53d6\u5230\u53e6\u4e00\u500b\u5c1a\u672a\u63d0\u4ea4\u7684\u4ea4\u6613\u7684\u8b8a\u66f4\u3002<\/p>\n<h3 id=\"%e7%89%b9%e9%bb%9e-ySGINFwkKd\">\u7279\u9ede<\/h3>\n<ul>\n<li><strong>\u907f\u514d\u9ad2\u8b80\uff1a<\/strong>\u5728\u300c\u70ba\u843d\u5be6\u7684\u8b80\u300d\u9694\u96e2\u7d1a\u5225\u4e0b\uff0c\u4ea4\u6613\u4e0d\u6703\u8b80\u53d6\u5230\u672a\u63d0\u4ea4\u7684\u8cc7\u6599\uff0c\u5f9e\u800c\u907f\u514d\u4e86\u9ad2\u8b80\u7684\u60c5\u6cc1\u3002<\/li>\n<li><strong>\u63d0\u9ad8\u8cc7\u6599\u4e00\u81f4\u6027\uff1a<\/strong>\u7531\u65bc\u53ea\u8b80\u53d6\u5df2\u63d0\u4ea4\u7684\u8cc7\u6599\uff0c\u9019\u6709\u52a9\u65bc\u63d0\u9ad8\u8cc7\u6599\u7684\u4e00\u81f4\u6027\u548c\u53ef\u9760\u6027\u3002<\/li>\n<li><strong>\u6027\u80fd\u512a\u5316\uff1a<\/strong>\u76f8\u6bd4\u65bc\u66f4\u9ad8\u7684\u9694\u96e2\u7d1a\u5225\uff0c\u300c\u70ba\u843d\u5be6\u7684\u8b80\u300d\u5728\u6027\u80fd\u4e0a\u901a\u5e38\u66f4\u5177\u512a\u52e2\uff0c\u56e0\u70ba\u5b83\u4e0d\u9700\u8981\u9396\u5b9a\u6574\u500b\u8cc7\u6599\u96c6\u3002<\/li>\n<\/ul>\n<h3 id=\"%e4%bd%bf%e7%94%a8%e7%af%84%e4%be%8b-ySGINFwkKd\">\u4f7f\u7528\u7bc4\u4f8b<\/h3>\n<p>\u4ee5\u4e0b\u662f\u4e00\u500b\u7c21\u55ae\u7684SQL\u7bc4\u4f8b\uff0c\u5c55\u793a\u5982\u4f55\u5728DB2\u4e2d\u8a2d\u7f6e\u300c\u70ba\u843d\u5be6\u7684\u8b80\u300d\u9694\u96e2\u7d1a\u5225\uff1a<\/p>\n<pre><code>\nSET TRANSACTION ISOLATION LEVEL READ COMMITTED;\n\nSELECT * FROM orders WHERE order_date &gt; '2023-01-01';\n<\/code><\/pre>\n<p>\u5728\u9019\u500b\u7bc4\u4f8b\u4e2d\uff0c\u4ea4\u6613\u5c07\u53ea\u8b80\u53d6\u57282023\u5e741\u67081\u65e5\u4e4b\u5f8c\u5df2\u63d0\u4ea4\u7684\u8a02\u55ae\u8cc7\u6599\u3002<\/p>\n<h2 id=\"%e9%81%a9%e7%94%a8%e5%a0%b4%e6%99%af-ySGINFwkKd\">\u9069\u7528\u5834\u666f<\/h2>\n<p>\u300c\u70ba\u843d\u5be6\u7684\u8b80\u300d\u9694\u96e2\u7d1a\u5225\u9069\u5408\u65bc\u5927\u591a\u6578\u696d\u52d9\u61c9\u7528\uff0c\u7279\u5225\u662f\u90a3\u4e9b\u9700\u8981\u5373\u6642\u67e5\u8a62\u8cc7\u6599\u4f46\u53c8\u4e0d\u5e0c\u671b\u53d7\u5230\u672a\u63d0\u4ea4\u8b8a\u66f4\u5f71\u97ff\u7684\u5834\u666f\u3002\u4f8b\u5982\uff0c\u96fb\u5b50\u5546\u52d9\u7db2\u7ad9\u5728\u986f\u793a\u7522\u54c1\u5eab\u5b58\u6642\uff0c\u901a\u5e38\u6703\u4f7f\u7528\u6b64\u9694\u96e2\u7d1a\u5225\uff0c\u4ee5\u78ba\u4fdd\u9867\u5ba2\u770b\u5230\u7684\u5eab\u5b58\u6578\u64da\u662f\u6e96\u78ba\u7684\u3002<\/p>\n<h2 id=\"%e7%b5%90%e8%ab%96-ySGINFwkKd\">\u7d50\u8ad6<\/h2>\n<p>DB2\u7684\u300c\u70ba\u843d\u5be6\u7684\u8b80\u300d\u9694\u96e2\u7d1a\u5225\u662f\u4e00\u500b\u5e73\u8861\u6027\u80fd\u548c\u8cc7\u6599\u4e00\u81f4\u6027\u7684\u6709\u6548\u9078\u64c7\u3002\u5b83\u80fd\u5920\u907f\u514d\u9ad2\u8b80\u554f\u984c\uff0c\u4e26\u78ba\u4fdd\u4ea4\u6613\u4e4b\u9593\u7684\u8cc7\u6599\u4e00\u81f4\u6027\uff0c\u9069\u5408\u65bc\u591a\u6578\u696d\u52d9\u61c9\u7528\u3002\u9078\u64c7\u5408\u9069\u7684\u9694\u96e2\u7d1a\u5225\u5c0d\u65bc\u8cc7\u6599\u5eab\u7684\u6027\u80fd\u548c\u53ef\u9760\u6027\u81f3\u95dc\u91cd\u8981\u3002<\/p>\n<p>\u5982\u9700\u4e86\u89e3\u66f4\u591a\u95dc\u65bcDB2\u53ca\u5176\u9694\u96e2\u7d1a\u5225\u7684\u8cc7\u8a0a\uff0c\u6216\u662f\u5c0b\u627e\u5408\u9069\u7684 <a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a> \u89e3\u6c7a\u65b9\u6848\uff0c\u8acb\u8a2a\u554f\u6211\u5011\u7684\u7db2\u7ad9\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4e86\u89e3DB2\u9694\u96e2\u7d1a\u5225\u4e2d\u7684\u843d\u5be6\u8b80\uff0c\u78ba\u4fdd\u6578\u64da\u4e00\u81f4\u6027\u8207\u6e96\u78ba\u6027\uff0c\u63d0\u5347\u6578\u64da\u5eab\u64cd\u4f5c\u7684\u53ef\u9760\u6027\u8207\u6027\u80fd\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-60501","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/60501","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=60501"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/60501\/revisions"}],"predecessor-version":[{"id":60502,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/60501\/revisions\/60502"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=60501"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=60501"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=60501"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}