{"id":2228,"date":"2012-07-05T04:02:55","date_gmt":"2012-07-05T04:02:55","guid":{"rendered":"http:\/\/enjoyasp.net\/?p=2228"},"modified":"2012-07-05T04:02:55","modified_gmt":"2012-07-05T04:02:55","slug":"%e6%b8%b8%e6%a0%87","status":"publish","type":"post","link":"https:\/\/enjoyasp.net\/index.php\/2012\/07\/05\/%e6%b8%b8%e6%a0%87\/","title":{"rendered":"\u6e38\u6807"},"content":{"rendered":"<p><span><span id=\"_ctl5_ctlTopic\"><span id=\"_ctl5_ctlTopic_ctlPanelBar\"><span id=\"_ctl5_ctlTopic_ctlPanelBar_ctlTopicsRepeater__ctl22_lblFullMessage\">\u4f7f\u7528<\/span><\/span><\/span><\/span>\u6e38\u6807\u7684\u6700\u597d\u65b9\u5f0f\u662f\u4e0d\u7528\u6e38\u6807\u3002<br \/>\n<span><span id=\"_ctl5_ctlTopic\"><span id=\"_ctl5_ctlTopic_ctlPanelBar\"><span id=\"_ctl5_ctlTopic_ctlPanelBar_ctlTopicsRepeater__ctl22_lblFullMessage\">why cursor is slow,It acquires locks which table variable does not do, and that is why Cursor is slow.<\/span><\/span><\/span><\/span><\/p>\n<p>\u6e38\u6807\u66ff\u4ee3\u65b9\u6848\uff1a<\/p>\n<pre class=\"brush:sql;first-line:1;pad-line-numbers:true;highlight:null;collapse:false;\">\r\n--Declare variables\r\nDECLARE @item_category_id INT\r\nDeclare @X BIGINT\r\nSet @X = 0\r\n--Declare a memory table\r\nDECLARE @item_table TABLE (item_category_id INT)\r\n\r\nINSERT INTO @item_table(item_category_id)\r\nSELECT  object_id\r\nFrom master.sys.objects c1(NOLOCK)\r\n\r\n--WHILE @loop_counter &gt; 0 AND @item_category_counter &lt;= @loop_counter\r\nWHILE (SELECT COUNT(1) FROM @item_table) &gt; 0\r\nBEGIN\r\n    SELECT TOP 1 @item_category_id = item_category_id\r\n    FROM @item_table \r\n    \r\n    --\u5904\u7406\r\n    Set @X = @X + @item_category_id\r\n    \r\n   delete from @item_table where item_category_id = @item_category_id\r\nEND\r\nPRINT @X\r\n\r\n\r\n\r\n<\/pre>\n","protected":false},"excerpt":{"rendered":"<p>\u4f7f\u7528\u6e38\u6807\u7684\u6700\u597d\u65b9\u5f0f\u662f\u4e0d\u7528\u6e38\u6807\u3002 why cursor is slow,It acquires locks wh [&hellip;]<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[36],"tags":[],"class_list":["post-2228","post","type-post","status-publish","format-standard","hentry","category-sql-server"],"blocksy_meta":[],"_links":{"self":[{"href":"https:\/\/enjoyasp.net\/index.php\/wp-json\/wp\/v2\/posts\/2228","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/enjoyasp.net\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/enjoyasp.net\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/enjoyasp.net\/index.php\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/enjoyasp.net\/index.php\/wp-json\/wp\/v2\/comments?post=2228"}],"version-history":[{"count":0,"href":"https:\/\/enjoyasp.net\/index.php\/wp-json\/wp\/v2\/posts\/2228\/revisions"}],"wp:attachment":[{"href":"https:\/\/enjoyasp.net\/index.php\/wp-json\/wp\/v2\/media?parent=2228"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/enjoyasp.net\/index.php\/wp-json\/wp\/v2\/categories?post=2228"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/enjoyasp.net\/index.php\/wp-json\/wp\/v2\/tags?post=2228"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}