{"id":179024,"date":"2024-11-08T22:22:19","date_gmt":"2024-11-08T14:22:19","guid":{"rendered":"https:\/\/server.hk\/cnblog\/179024\/"},"modified":"2024-11-08T22:22:20","modified_gmt":"2024-11-08T14:22:20","slug":"%e5%a6%82%e4%bd%95%e4%bf%ae%e5%be%a9-postgresql-%e9%8c%af%e8%aa%a4%e4%bb%a3%e7%a2%bc%ef%bc%9a42p03-duplicate_cursor%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/179024\/","title":{"rendered":"\u5982\u4f55\u4fee\u5fa9 PostgreSQL \u932f\u8aa4\u4ee3\u78bc\uff1a42P03 &#8211; duplicate_cursor\uff1f"},"content":{"rendered":"<h1 id=\"%e5%a6%82%e4%bd%95%e4%bf%ae%e5%be%a9-postgresql-%e9%8c%af%e8%aa%a4%e4%bb%a3%e7%a2%bc%ef%bc%9a42p03-duplicate_cursor-hBcgHiKpqG\">\u5982\u4f55\u4fee\u5fa9 PostgreSQL \u932f\u8aa4\u4ee3\u78bc\uff1a42P03 &#8211; duplicate_cursor<\/h1>\n<p>\u5728\u4f7f\u7528 PostgreSQL \u6578\u64da\u5eab\u6642\uff0c\u958b\u767c\u8005\u53ef\u80fd\u6703\u9047\u5230\u5404\u7a2e\u932f\u8aa4\u4ee3\u78bc\uff0c\u5176\u4e2d\u4e4b\u4e00\u662f\u932f\u8aa4\u4ee3\u78bc 42P03\uff0c\u8a72\u932f\u8aa4\u901a\u5e38\u8868\u793a\u300cduplicate_cursor\u300d\u3002\u9019\u610f\u5473\u8457\u5728\u540c\u4e00\u500b\u67e5\u8a62\u4e0a\u4e0b\u6587\u4e2d\uff0c\u5617\u8a66\u4f7f\u7528\u76f8\u540c\u540d\u7a31\u7684\u6e38\u6a19\u9032\u884c\u591a\u6b21\u5b9a\u7fa9\u3002\u672c\u6587\u5c07\u6df1\u5165\u63a2\u8a0e\u6b64\u932f\u8aa4\u7684\u539f\u56e0\u53ca\u5176\u89e3\u6c7a\u65b9\u6848\u3002<\/p>\n<h2 id=\"%e4%bb%80%e9%ba%bc%e6%98%af%e6%b8%b8%e6%a8%99%ef%bc%9f-hBcgHiKpqG\">\u4ec0\u9ebc\u662f\u6e38\u6a19\uff1f<\/h2>\n<p>\u5728 PostgreSQL \u4e2d\uff0c\u6e38\u6a19\u662f\u4e00\u7a2e\u6578\u64da\u5eab\u5c0d\u8c61\uff0c\u5141\u8a31\u7528\u6236\u9010\u884c\u6aa2\u7d22\u67e5\u8a62\u7d50\u679c\u3002\u6e38\u6a19\u901a\u5e38\u7528\u65bc\u9700\u8981\u9010\u6b65\u8655\u7406\u5927\u91cf\u6578\u64da\u7684\u60c5\u6cc1\u3002\u4f7f\u7528\u6e38\u6a19\u7684\u57fa\u672c\u6b65\u9a5f\u5305\u62ec\uff1a<\/p>\n<ul>\n<li>\u5b9a\u7fa9\u6e38\u6a19<\/li>\n<li>\u6253\u958b\u6e38\u6a19<\/li>\n<li>\u63d0\u53d6\u6578\u64da<\/li>\n<li>\u95dc\u9589\u6e38\u6a19<\/li>\n<\/ul>\n<h2 id=\"%e9%8c%af%e8%aa%a4%e4%bb%a3%e7%a2%bc-42p03-%e7%9a%84%e5%8e%9f%e5%9b%a0-hBcgHiKpqG\">\u932f\u8aa4\u4ee3\u78bc 42P03 \u7684\u539f\u56e0<\/h2>\n<p>\u7576\u4f60\u5728\u540c\u4e00\u500b\u6703\u8a71\u4e2d\u591a\u6b21\u5b9a\u7fa9\u76f8\u540c\u540d\u7a31\u7684\u6e38\u6a19\u6642\uff0c\u5c31\u6703\u51fa\u73fe\u932f\u8aa4\u4ee3\u78bc 42P03\u3002\u9019\u901a\u5e38\u767c\u751f\u5728\u4ee5\u4e0b\u60c5\u6cc1\uff1a<\/p>\n<ul>\n<li>\u5728\u540c\u4e00\u500b SQL \u8173\u672c\u4e2d\u91cd\u8907\u5b9a\u7fa9\u6e38\u6a19\u3002<\/li>\n<li>\u5728 PL\/pgSQL \u51fd\u6578\u4e2d\u591a\u6b21\u5b9a\u7fa9\u76f8\u540c\u540d\u7a31\u7684\u6e38\u6a19\u3002<\/li>\n<li>\u5728\u4e0d\u540c\u7684\u4e8b\u52d9\u4e2d\u4f7f\u7528\u76f8\u540c\u540d\u7a31\u7684\u6e38\u6a19\uff0c\u4f46\u672a\u6b63\u78ba\u95dc\u9589\u524d\u4e00\u500b\u6e38\u6a19\u3002<\/li>\n<\/ul>\n<h2 id=\"%e5%a6%82%e4%bd%95%e4%bf%ae%e5%be%a9%e9%8c%af%e8%aa%a4-42p03-hBcgHiKpqG\">\u5982\u4f55\u4fee\u5fa9\u932f\u8aa4 42P03<\/h2>\n<p>\u4fee\u5fa9\u6b64\u932f\u8aa4\u7684\u95dc\u9375\u5728\u65bc\u78ba\u4fdd\u6bcf\u500b\u6e38\u6a19\u540d\u7a31\u90fd\u662f\u552f\u4e00\u7684\uff0c\u6216\u8005\u5728\u91cd\u65b0\u5b9a\u7fa9\u6e38\u6a19\u4e4b\u524d\u6b63\u78ba\u95dc\u9589\u5b83\u3002\u4ee5\u4e0b\u662f\u4e00\u4e9b\u5177\u9ad4\u7684\u89e3\u6c7a\u65b9\u6848\uff1a<\/p>\n<h3 id=\"1-%e7%a2%ba%e4%bf%9d%e6%b8%b8%e6%a8%99%e5%90%8d%e7%a8%b1%e5%94%af%e4%b8%80-hBcgHiKpqG\">1. \u78ba\u4fdd\u6e38\u6a19\u540d\u7a31\u552f\u4e00<\/h3>\n<p>\u5728\u5b9a\u7fa9\u6e38\u6a19\u6642\uff0c\u4f7f\u7528\u5177\u6709\u63cf\u8ff0\u6027\u7684\u540d\u7a31\uff0c\u4e26\u78ba\u4fdd\u5728\u540c\u4e00\u500b\u4e0a\u4e0b\u6587\u4e2d\u4e0d\u6703\u91cd\u8907\u3002\u4f8b\u5982\uff1a<\/p>\n<pre><code>DECLARE\n    my_cursor CURSOR FOR SELECT * FROM my_table;\n<\/code><\/pre>\n<p>\u5982\u679c\u9700\u8981\u591a\u500b\u6e38\u6a19\uff0c\u8acb\u4f7f\u7528\u4e0d\u540c\u7684\u540d\u7a31\uff1a<\/p>\n<pre><code>DECLARE\n    my_cursor1 CURSOR FOR SELECT * FROM my_table;\n    my_cursor2 CURSOR FOR SELECT * FROM another_table;\n<\/code><\/pre>\n<h3 id=\"2-%e6%ad%a3%e7%a2%ba%e9%97%9c%e9%96%89%e6%b8%b8%e6%a8%99-hBcgHiKpqG\">2. \u6b63\u78ba\u95dc\u9589\u6e38\u6a19<\/h3>\n<p>\u5728\u91cd\u65b0\u5b9a\u7fa9\u6e38\u6a19\u4e4b\u524d\uff0c\u78ba\u4fdd\u5df2\u7d93\u95dc\u9589\u4e86\u4e4b\u524d\u7684\u6e38\u6a19\u3002\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u8a9e\u53e5\u4f86\u95dc\u9589\u6e38\u6a19\uff1a<\/p>\n<pre><code>CLOSE my_cursor;\n<\/code><\/pre>\n<p>\u9019\u6a23\u53ef\u4ee5\u907f\u514d\u5728\u540c\u4e00\u500b\u6703\u8a71\u4e2d\u91cd\u8907\u5b9a\u7fa9\u6e38\u6a19\u7684\u60c5\u6cc1\u3002<\/p>\n<h3 id=\"3-%e4%bd%bf%e7%94%a8%e6%a2%9d%e4%bb%b6%e8%aa%9e%e5%8f%a5%e6%aa%a2%e6%9f%a5%e6%b8%b8%e6%a8%99%e6%98%af%e5%90%a6%e5%ad%98%e5%9c%a8-hBcgHiKpqG\">3. \u4f7f\u7528\u689d\u4ef6\u8a9e\u53e5\u6aa2\u67e5\u6e38\u6a19\u662f\u5426\u5b58\u5728<\/h3>\n<p>\u5728 PL\/pgSQL \u4e2d\uff0c\u53ef\u4ee5\u4f7f\u7528\u689d\u4ef6\u8a9e\u53e5\u4f86\u6aa2\u67e5\u6e38\u6a19\u662f\u5426\u5df2\u7d93\u5b58\u5728\uff0c\u5f9e\u800c\u907f\u514d\u91cd\u8907\u5b9a\u7fa9\u3002\u4f8b\u5982\uff1a<\/p>\n<pre><code>IF NOT FOUND THEN\n    DECLARE my_cursor CURSOR FOR SELECT * FROM my_table;\nEND IF;\n<\/code><\/pre>\n<h2 id=\"%e7%b8%bd%e7%b5%90-hBcgHiKpqG\">\u7e3d\u7d50<\/h2>\n<p>\u932f\u8aa4\u4ee3\u78bc 42P03 &#8211; duplicate_cursor \u662f PostgreSQL \u4e2d\u5e38\u898b\u7684\u932f\u8aa4\u4e4b\u4e00\uff0c\u901a\u5e38\u7531\u65bc\u6e38\u6a19\u540d\u7a31\u91cd\u8907\u6216\u672a\u6b63\u78ba\u95dc\u9589\u6e38\u6a19\u6240\u5f15\u8d77\u3002\u901a\u904e\u78ba\u4fdd\u6e38\u6a19\u540d\u7a31\u7684\u552f\u4e00\u6027\u3001\u6b63\u78ba\u95dc\u9589\u6e38\u6a19\u4ee5\u53ca\u4f7f\u7528\u689d\u4ef6\u8a9e\u53e5\u6aa2\u67e5\u6e38\u6a19\u7684\u5b58\u5728\uff0c\u53ef\u4ee5\u6709\u6548\u5730\u4fee\u5fa9\u6b64\u932f\u8aa4\u3002\u5c0d\u65bc\u9700\u8981\u9ad8\u6548\u6578\u64da\u8655\u7406\u7684\u61c9\u7528\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\u6027\u80fd\u3002\u4e86\u89e3\u66f4\u591a\u95dc\u65bc <a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a> \u7684\u8cc7\u8a0a\uff0c\u8acb\u8a2a\u554f\u6211\u5011\u7684\u7db2\u7ad9\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4e86\u89e3\u5982\u4f55\u4fee\u5fa9 PostgreSQL \u932f\u8aa4\u4ee3\u78bc 42P03 &#8211; duplicate_cursor\uff0c\u89e3\u6c7a\u91cd\u8907\u6e38\u6a19\u554f\u984c\uff0c\u78ba\u4fdd\u6578\u64da\u5eab\u64cd\u4f5c\u9806\u5229\u9032\u884c\u3002<\/p>\n","protected":false},"author":0,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-179024","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/179024","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"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=179024"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/179024\/revisions"}],"predecessor-version":[{"id":179025,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/179024\/revisions\/179025"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=179024"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=179024"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=179024"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}