{"id":2665,"date":"2015-07-13T22:03:37","date_gmt":"2015-07-13T14:03:37","guid":{"rendered":"http:\/\/blog.qdac.cc\/?p=2665"},"modified":"2015-07-14T13:51:07","modified_gmt":"2015-07-14T05:51:07","slug":"qdb-qdataset-%e6%94%af%e6%8c%81%e4%b8%bb%e4%bb%8e%e8%a1%a8%e6%96%b9%e5%bc%8f%e8%af%b4%e6%98%8e","status":"publish","type":"post","link":"https:\/\/blog.qdac.cc\/?p=2665","title":{"rendered":"[QDB] QDataSet \u652f\u6301\u4e3b\u4ece\u8868\u65b9\u5f0f\u8bf4\u660e"},"content":{"rendered":"

QDataSet \u505a\u4e3a QDB \u7684\u91cd\u8981\u7ec4\u6210\u90e8\u5206\uff0c\u76ee\u524d\u5df2\u7ecf\u652f\u6301\u4e3b\u4ece\u8868\u7684\u8bbe\u5b9a\u3002QDataSet \u7684\u4e3b\u4ece\u8868\u652f\u6301\u4e0e\u4e00\u822c\u7684\u6570\u636e\u96c6\u7565\u6709\u4e0d\u540c\uff0c\u6211\u505a\u4e86\u4e00\u4e9b\u7b80\u5316\u548c\u589e\u5f3a\u5904\u7406\u3002\u8bbe\u5b9a\u4e3b\u4ece\u8868\u7b2c\u4e00\u6b65\u4e0e\u4e00\u822c\u7684\u6570\u636e\u96c6\u6ca1\u6709\u4ec0\u4e48\u4e0d\u540c\uff0c\u8bbe\u7f6e\u4ece\u8868\u7684 MasterSource \u4e3a\u4e3b\u8868\u7684\u6570\u636e\u6e90\uff08 DataSource \uff09\uff0c\u4f46\u63a5\u4e0b\u6765\u5c31\u6709\u6240\u4e0d\u540c\u4e86\uff1a
\n1\u3001\u76f4\u63a5\u901a\u8fc7\u8bbe\u7f6e MasterFields \u6765\u6fc0\u6d3b\u4e3b\u4ece\u5173\u7cfb
\nMasterFields \u7684\u683c\u5f0f\u8fdb\u884c\u4e86\u589e\u5f3a\uff0c\u4e0d\u518d\u662f\u5206\u522b\u8bbe\u7f6e MasterFields \u548c IndexFields \u3002\u76f4\u63a5\u8bbe\u5b9a\u5173\u952e\u5b57\u6bb5\u5173\u8054\u5373\u53ef\uff0c\u683c\u5f0f\u4e3a\uff1a<\/p>\n

\u4e3b\u8868\u5b57\u6bb5=\u4ece\u8868\u5b57\u6bb5[;\u4e3b\u8868\u5b57\u6bb5=\u4ece\u8868\u5b57\u6bb5]…<\/p><\/blockquote>\n

\u5982\u679c\u4e3b\u8868\u5b57\u6bb5\u548c\u4ece\u8868\u5b57\u6bb5\u540d\u4e00\u6837\uff0c\u53ef\u4ee5\u53ea\u5199\u4e3b\u8868\u5b57\u6bb5\uff0c\u591a\u4e2a\u5b57\u6bb5\u95f4\u901a\u8fc7\u5206\u53f7\u6216\u9017\u53f7\u76f4\u63a5\u5206\u9694\u5373\u53ef\uff0c\u793a\u4f8b\u5982\u4e0b\uff1a<\/p>\n

FDetailDataSet.MasterSource := DataSource1;\r\nFDetailDataSet.MasterFields := 'id=MasterId';<\/pre>\n
2\u3001\u901a\u8fc7 OnMasterChanged \u4e8b\u4ef6\u6765\u83b7\u53d6\u4ece\u8868\u6570\u636e<\/p>\n
OnMasterChanged \u4e8b\u4ef6\u5728\u4e3b\u8868\u8bb0\u5f55\u53d8\u66f4\u540e\u4f1a\u89e6\u53d1\u4e00\u6b21\uff0c\u6240\u4ee5\u5728\u6211\u4eec\u5e76\u4e0d\u60f3\u4e00\u6b21\u6027\u83b7\u53d6\u5230\u6240\u6709\u7684\u4ece\u8868\u6570\u636e\u65f6\uff0c\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7\u54cd\u5e94\u8fd9\u4e00\u4e8b\u4ef6\u6765\u52a8\u6001\u83b7\u53d6\u660e\u7ec6\u6570\u636e\uff0c\u5982\uff1a<\/p>\n
...\r\nFDetailDataSet.OnMasterChanged := DoMasterChanged;\r\nFDetailDataSet.MasterSource := DataSource1;\r\n...\r\nrocedure TForm1.DoMasterChanged(ADataSet: TDataSet);\r\nbegin\r\n  FProv.OpenDataSet(FDetailDataSet, 'select * from pg_attribute where attrelid='\r\n    + FMasterDataSet.FieldByName('oid').AsString);\r\nend;<\/pre>\n
\"masterdetail\"<\/a><\/p>\n
\u597d\u4e86\uff0c\u65b9\u6cd52\u867d\u7136\u6bcf\u6b21\u53ea\u53d6\u90e8\u5206\u660e\u7ec6\u8bb0\u5f55\uff0c\u4f46\u95ee\u9898\u662f\u5f53\u6211\u4eec\u91cd\u590d\u6d4f\u89c8\u8bb0\u5f55\u65f6\uff0c\u8fd8\u4f1a\u9700\u8981\u91cd\u590d\u67e5\u8be2\u3002\u8fd9\u663e\u7136\u4e0e\u6211\u4eec\u51cf\u5c11\u7f51\u7edc\u6570\u636e\u4f20\u8f93\u7684\u601d\u8def\u662f\u80cc\u9053\u800c\u9a70\u7684\uff0c\u6240\u4ee5\uff0c\u6211\u4eec\u53ef\u4ee5\u8fdb\u4e00\u6b65\u4f18\u5316\uff1a<\/p>\n
procedure TForm1.DoMasterChanged(ADataSet: TDataSet);\r\nvar\r\n  S: QStringW;\r\n  ASub: TQDataSet;\r\n  I: Integer;\r\nbegin\r\n  try\r\n    Inc(FRequests);\r\n    S := 'select * from pg_attribute where attrelid=' +\r\n      FMasterDataSet.FieldByName('oid').AsString;\r\n    for I := 0 to FDetailDataSet.RecordsetCount - 1 do\r\n    begin\r\n      if FDetailDataSet.Recordsets[I].CommandText = S then\r\n      begin\r\n        FDetailDataSet.ActiveRecordset := I;\r\n        Inc(FHits);\r\n        Exit;\r\n      end;\r\n    end;\r\n    ASub := FProv.OpenDataSet(S);\r\n    FDetailDataSet.AddDataSet(ASub);\r\n    FDetailDataSet.ActiveRecordset := FDetailDataSet.RecordsetCount - 1;\r\n  finally\r\n    Panel2.Caption := '\u603b\u8ba1: ' + IntToStr(FRequests) + ' \u6b21\u8bf7\u6c42\uff0c\u7f13\u5b58\u547d\u4e2d:' +\r\n      IntToStr(FHits) + '\u6b21';\r\n  end;\r\nend;<\/pre>\n
\u8fd9\u91cc\u6211\u52a0\u5165\u4e86\u4e00\u4e2a\u7edf\u8ba1\u6765\u8ba1\u7b97\u51cf\u5c11\u67e5\u8be2\u7684\u6b21\u6570\uff0c\u770b\u6548\u679c\u5427\uff1a<\/p>\n
\"multidscached\"<\/a><\/p>\n
 <\/p>\n","protected":false},"excerpt":{"rendered":"
QDataSet \u505a\u4e3a QDB \u7684\u91cd\u8981\u7ec4 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[8,9,66],"tags":[],"class_list":["post-2665","post","type-post","status-publish","format-standard","hentry","category-delphi","category-qdac","category-qdb"],"views":11780,"_links":{"self":[{"href":"https:\/\/blog.qdac.cc\/index.php?rest_route=\/wp\/v2\/posts\/2665","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.qdac.cc\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.qdac.cc\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.qdac.cc\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.qdac.cc\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2665"}],"version-history":[{"count":5,"href":"https:\/\/blog.qdac.cc\/index.php?rest_route=\/wp\/v2\/posts\/2665\/revisions"}],"predecessor-version":[{"id":2675,"href":"https:\/\/blog.qdac.cc\/index.php?rest_route=\/wp\/v2\/posts\/2665\/revisions\/2675"}],"wp:attachment":[{"href":"https:\/\/blog.qdac.cc\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2665"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.qdac.cc\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2665"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.qdac.cc\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2665"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}