Learn OLE DB Development with Visual C++ 6.0
Nathan Wallace
Wordware Publishing, Inc.
Library of Congress Cataloging-in-Publication Data Wallace, Nathan Learn OLE DB Development with Visual C++ 6.0 / by Nathan Wallace. p. cm. Includes index. ISBN 1-55622-634-9 (pbk.) 1. Microsoft Visual C++. 2. Database management. 3. OLE (Computer file) I. Title. QA76.73.C153W314 1999 005.7—dc21 99-34012 CIP
© 2000, Wordware Publishing, Inc. All Rights Reserved 2320 Los Rios Boulevard Plano, Texas 75074 No part of this book may be reproduced in any form or by any means without permission in writing from Wordware Publishing, Inc. Printed in the United States of America
ISBN 1-55622-634-9 10 9 8 7 6 5 4 3 2 1 0001
Product names mentioned are used for identification purposes only and may be trademarks of their respective companies. All inquiries for volume purchases of this book should be addressed to Wordware Publishing, Inc., at the above address. Telephone inquiries may be made by calling: (972) 423-0090
Dedication To Beth Kohler. Thanks for all the help and patience.
Acknowledgments Like so many complex undertakings, this book would not have existed without support from many people beside the guy who tickled the keyboard. I’d like to take a moment to thank Beth Kohler, who tried to make vague sense of my frantic scribblings. Any leftover typos or illogic is entirely mine. A big thank you to Russell Stultz, owner of Wordware Publishing, for his care and thoughtfulness in a business all too often filled with the reverse. And a final thanks to my wife, Laura, for her kindness, support, and patience during the creative process. Above all, I need to thank the Totoro, because without him, I wouldn’t be here at all!
Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiii Chapter One
A COM Primer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 What is COM? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 How Did COM Happen? . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Why Do We Need COM? . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 How COM Works. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 The COM Server. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 The COM ClassFactory . . . . . . . . . . . . . . . . . . . . . . . . . . 8 The COM Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 The COM Reference Count . . . . . . . . . . . . . . . . . . . . . . . . 9 The COM System in Windows . . . . . . . . . . . . . . . . . . . . . . 10 The COM Client . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 COM is Static, Automation is Dynamic. . . . . . . . . . . . . . . . . . . 10 Automation Opens COM to the World . . . . . . . . . . . . . . . . . . . 12 From Automation to OCX to ActiveX . . . . . . . . . . . . . . . . . . . . 13 ActiveX Controls are Automation Servers with a User Interface . . . . . . 16 Stock Properties and Property Pages Standardize ActiveX Control Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Connection Points Allow Events to be Sent from ActiveX Controls to Containers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Persistence Allows ActiveX Controls to Save Their State Over Time. . . . 21 Where We Go From Here . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Chapter Two
An ATL Primer . . . . . . . . . . . . . . . . . . . ATL in Visual C++ . . . . . . . . . . . . . . . . . . Getting ATL for Older Visual C++ Versions . . . . ATL’s Online Documentation . . . . . . . . . . . . Creating ATL Projects with the ATL AppWizard . . . The New Dialog . . . . . . . . . . . . . . . . . . The ATL AppWizard . . . . . . . . . . . . . . . . The Confirmation Dialog. . . . . . . . . . . . . . Adding COM Interfaces with the ATL Object Wizard The Object Wizard Objects. . . . . . . . . . . . . The Object Wizard Controls . . . . . . . . . . . . The Object Wizard Miscellaneous Elements . . . . The Object Wizard Data Access Elements . . . . . The Object Wizard Names Tab . . . . . . . . . . . The Object Wizard Attributes Tab . . . . . . . . .
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n Contents Specialized Object Wizard Tabs . . . . . . . . . . . . . . . . . Creating Functions and Properties with the ATL Interface Wizards The ClassView Shortcut Menu . . . . . . . . . . . . . . . . . . The Add Method to Interface Dialog . . . . . . . . . . . . . . . The Add Property to Interface Dialog . . . . . . . . . . . . . . The Edit Attributes Dialog . . . . . . . . . . . . . . . . . . . . Some Advanced Topics for ATL Projects . . . . . . . . . . . . . . The Proxy Generator . . . . . . . . . . . . . . . . . . . . . . . Advanced Servers . . . . . . . . . . . . . . . . . . . . . . . . ATL Code (Templates and Macros, Oh My!) . . . . . . . . . . . . Templates Create Custom Classes from Standard C++ Code . . Macros Expand into Customized Code. . . . . . . . . . . . . . What’s New with ATL Version 3.0? . . . . . . . . . . . . . . . . . Version 3.0 Changes to the AppWizard . . . . . . . . . . . . . Version 3.0 Changes to the ATL Object Wizard . . . . . . . . . Version 3.0 Changes to the ClassView Context Menus . . . . . . The Add Windows Message Handler Option . . . . . . . . The Implement Connection Point Option . . . . . . . . . The Implement Interface Option . . . . . . . . . . . . . . Where We Go From Here . . . . . . . . . . . . . . . . . . . . . .
Chapter Three
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29 30 30 30 31 32 32 32 33 33 33 33 34 34 35 36 36 38 39 40
An MFC Primer. . . . . . . . . . . . . . . . . . . . . . . . . . . MFC in Visual C++ . . . . . . . . . . . . . . . . . . . . . . . . . MFC’s Online Documentation . . . . . . . . . . . . . . . . . . . Creating MFC Projects with the MFC ActiveX ControlWizard . . . . The New Dialog . . . . . . . . . . . . . . . . . . . . . . . . . . The MFC ActiveX ControlWizard . . . . . . . . . . . . . . . . . The Confirmation Dialog. . . . . . . . . . . . . . . . . . . . . . Working MFC Magic with the ClassWizard. . . . . . . . . . . . . . The ClassWizard Message Maps Tab . . . . . . . . . . . . . . . . The ClassWizard Member Variables Tab . . . . . . . . . . . . . . The ClassWizard Automation Tab . . . . . . . . . . . . . . . . . The ClassWizard ActiveX Events Tab. . . . . . . . . . . . . . . . The ClassWizard Class Info Tab . . . . . . . . . . . . . . . . . . Augmenting ActiveX Control Features with ClassWizard Dialogs . . The ClassWizard New Class Dialog . . . . . . . . . . . . . . . . The ClassWizard Add Method Dialog . . . . . . . . . . . . . . . The ClassWizard Add Property Dialog . . . . . . . . . . . . . . . The ClassWizard Add Event Dialog . . . . . . . . . . . . . . . . Some Advanced Topics for MFC ActiveX Control Projects . . . . . . Using Windows Events with ClassWizard . . . . . . . . . . . . . Editing Property Pages . . . . . . . . . . . . . . . . . . . . . . . Connecting Property Page Controls to ActiveX Control Properties with ClassWizard . . . . . . . . . . . . . . . . . . . . . . . . MFC Code (Classes and Macros, Oh My!) . . . . . . . . . . . . . . MFC Classes Encapsulate Much Windows Functionality in C++ Wrappers . . . . . . . . . . . . . . . . . . . . . . . . . . . . Macros Expand into Customized Code. . . . . . . . . . . . . . .
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Where We Go From Here . . . . . . . . . . . . . . . . . . . . . . . . . . 52 Chapter Four
An OLE DB Primer. . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 IAccessor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 IAccessor::AddRefAccessor. . . . . . . . . . . . . . . . . . . . . . . . 54 IAccessor::CreateAccessor . . . . . . . . . . . . . . . . . . . . . . . . 55 IAccessor::GetBindings. . . . . . . . . . . . . . . . . . . . . . . . . . 63 IAccessor::ReleaseAccessor . . . . . . . . . . . . . . . . . . . . . . . 65 IColumnsInfo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 IColumnsInfo::GetColumnInfo . . . . . . . . . . . . . . . . . . . . . . 67 IColumnsInfo::MapColumnIDs. . . . . . . . . . . . . . . . . . . . . . 74 ISourcesRowset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 ISourcesRowset::GetSourcesRowset . . . . . . . . . . . . . . . . . . . 75 IDBCreateSession. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 IDBCreateSession::CreateSession . . . . . . . . . . . . . . . . . . . . 79 IDBInfo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 IDBInfo::GetKeywords . . . . . . . . . . . . . . . . . . . . . . . . . . 80 IDBInfo::GetLiteralInfo . . . . . . . . . . . . . . . . . . . . . . . . . 84 IGetDataSource . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 IGetDataSource::GetDataSource . . . . . . . . . . . . . . . . . . . . . 90 IOpenRowset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 IOpenRowset::OpenRowset . . . . . . . . . . . . . . . . . . . . . . . 91 ISessionProperties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 ISessionProperties::GetProperties . . . . . . . . . . . . . . . . . . . . 95 ISessionProperties::SetProperties . . . . . . . . . . . . . . . . . . . . 97 IDBCreateCommand . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99 IDBCreateCommand::CreateCommand . . . . . . . . . . . . . . . . . 99 ITableDefinition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 ITableDefinition::AddColumn . . . . . . . . . . . . . . . . . . . . . 100 ITableDefinition::CreateTable . . . . . . . . . . . . . . . . . . . . . 102 ITableDefinition::DropColumn . . . . . . . . . . . . . . . . . . . . . 107 ITableDefinition::DropTable . . . . . . . . . . . . . . . . . . . . . . 108 ICommand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 ICommand::Cancel . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 ICommand::Execute . . . . . . . . . . . . . . . . . . . . . . . . . . 110 ICommand::GetDBSession . . . . . . . . . . . . . . . . . . . . . . . 116 ICommandProperties . . . . . . . . . . . . . . . . . . . . . . . . . . . 117 ICommandProperties::GetProperties . . . . . . . . . . . . . . . . . . 118 ICommandProperties::SetProperties . . . . . . . . . . . . . . . . . . 121 ICommandText . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123 ICommandText::GetCommandText . . . . . . . . . . . . . . . . . . . 124 ICommandText::SetCommandText . . . . . . . . . . . . . . . . . . . 125 IColumnsRowset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126 IColumnsRowset::GetAvailableColumns . . . . . . . . . . . . . . . . 127 IColumnsRowset::GetColumnsRowset . . . . . . . . . . . . . . . . . 128 Required Metadata Columns . . . . . . . . . . . . . . . . . . . . . . 132 Optional Metadata Columns . . . . . . . . . . . . . . . . . . . . . . 134 ICommandPrepare . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
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n Contents ICommandPrepare::Prepare . . . . . . . . . . . . ICommandPrepare::Unprepare . . . . . . . . . . . ICommandWithParameters . . . . . . . . . . . . . . ICommandWithParameters::GetParameterInfo . . . ICommandWithParameters::MapParameterNames . ICommandWithParameters::SetParameterInfo . . . IRowset . . . . . . . . . . . . . . . . . . . . . . . . IRowset::AddRefRows . . . . . . . . . . . . . . . IRowset::GetData . . . . . . . . . . . . . . . . . . IRowset::GetNextRows . . . . . . . . . . . . . . . IRowset::ReleaseRows . . . . . . . . . . . . . . . IRowset::RestartPosition . . . . . . . . . . . . . . IRowsetInfo . . . . . . . . . . . . . . . . . . . . . . IRowsetInfo::GetProperties . . . . . . . . . . . . . IRowsetInfo::GetReferencedRowset . . . . . . . . IRowsetInfo::GetSpecification . . . . . . . . . . . IRowsetChange . . . . . . . . . . . . . . . . . . . . IRowsetChange::DeleteRows . . . . . . . . . . . . IRowsetChange::InsertRow . . . . . . . . . . . . . IRowsetChange::SetData . . . . . . . . . . . . . . IRowsetUpdate . . . . . . . . . . . . . . . . . . . . IRowsetUpdate::GetOriginalData. . . . . . . . . . IRowsetUpdate::GetPendingRows . . . . . . . . . IRowsetUpdate::GetRowStatus . . . . . . . . . . . IRowsetUpdate::Undo . . . . . . . . . . . . . . . IRowsetUpdate::Update . . . . . . . . . . . . . . ITransaction . . . . . . . . . . . . . . . . . . . . . . ITransaction::Abort . . . . . . . . . . . . . . . . . ITransaction::Commit . . . . . . . . . . . . . . . ITransaction::GetTransactionInfo . . . . . . . . . . ITransactionOptions. . . . . . . . . . . . . . . . . . ITransactionOptions::GetOptions . . . . . . . . . . ITransactionOptions::SetOptions . . . . . . . . . . ITransactionObject . . . . . . . . . . . . . . . . . . ITransactionObject::GetTransactionObject . . . . . ITransactionJoin. . . . . . . . . . . . . . . . . . . . ITransactionJoin::GetOptionsObject . . . . . . . . ITransactionJoin::JoinTransaction . . . . . . . . . IRowsetIndex . . . . . . . . . . . . . . . . . . . . . IRowsetIndex::GetIndexInfo . . . . . . . . . . . . IRowsetIndex::Seek. . . . . . . . . . . . . . . . . IRowsetIndex::SetRange . . . . . . . . . . . . . . IErrorRecords . . . . . . . . . . . . . . . . . . . . . IErrorRecords::AddErrorRecord . . . . . . . . . . IErrorRecords::GetBasicErrorInfo. . . . . . . . . . IErrorRecords::GetCustomErrorObject . . . . . . . IErrorRecords::GetErrorInfo . . . . . . . . . . . . IErrorRecords::GetErrorParameters. . . . . . . . .
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Chapter Five
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IErrorRecords::GetRecordCount . . IErrorLookup . . . . . . . . . . . . . IErrorLookup::GetErrorDescription. IErrorLookup::GetHelpInfo . . . . . IErrorLookup::ReleaseErrors . . . . ISQLErrorInfo . . . . . . . . . . . . . ISQLErrorInfo::GetSQLInfo . . . . . Where We Go From Here . . . . . . .
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227 228 229 230 231 232 232 233
An ADO Primer . . . . . . . . . . ADO Collections . . . . . . . . . . . The Errors Collection . . . . . . . The Fields Collection . . . . . . . The Parameters Collection . . . . The Properties Collection . . . . . The ADO Connection Object . . . The ADO Command Object . . . . The ADO Recordset Object . . . . The ADO Field Object . . . . . . The ADO Error Object . . . . . . The ADO Property Object. . . . . The ADO Parameter Object . . . . ADO Events . . . . . . . . . . . . . BeginTransComplete Event . . . . CommitTransComplete Event. . . ConnectComplete Event . . . . . Disconnect Event . . . . . . . . . EndOfRecordset Event . . . . . . ExecuteComplete Event . . . . . FetchComplete Event . . . . . . . FetchProgress Event . . . . . . . FieldChangeComplete Event . . . InfoMessage Event . . . . . . . . MoveComplete Event . . . . . . . OnError Event . . . . . . . . . . OnReadyStateChange Event . . . RecordChangeComplete Event . . RecordsetChangeComplete Event. RollbackTransComplete Event . . WillChangeField Event . . . . . . WillChangeRecord Event . . . . . WillChangeRecordset Event . . . WillConnect Event . . . . . . . . WillExecute Event . . . . . . . . WillMove Event . . . . . . . . . . Where We Go From Here . . . . . .
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Chapter Six
Creating and Using Simple OLE DB Providers and Consumers with ATL and MFC . . . . . . . . . . . . . . . . . . . . . . . . . . . 325 OLE DB Template Changes are Required in ATL . . . . . . . . . . . . . 325 Creating an OLE DB Provider COM DLL with ATL . . . . . . . . . . . . 326 What the Wizard Wrought . . . . . . . . . . . . . . . . . . . . . . . 329 Gentlemen, Start Your Keyboards! . . . . . . . . . . . . . . . . . . . 341 Returning a Custom Rowset . . . . . . . . . . . . . . . . . . . . . . 342 Defining a Custom User Record . . . . . . . . . . . . . . . . . . . . 345 Redefining the Rowset Implementation Template to Support Bookmarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 347 Implementing Bookmarks in the Custom Rowset Implementation . . . 350 Implementing Bookmarks in the Custom IRowsetLocate Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . 355 Implementing Variable COLUMNIFO in the Custom Rowset Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . 360 Disabling Schema Support . . . . . . . . . . . . . . . . . . . . . . . 364 Building the OLE DB Provider DLL . . . . . . . . . . . . . . . . . . . 368 Creating an OLE DB Consumer Application with MFC . . . . . . . . . . 368 Building the MFC OLE DB Consumer Application . . . . . . . . . . . 383 Creating the Text File Database and Testing the OLE DB Provider with the MFC Consumer Application . . . . . . . . . . . . . . . . . . . . 384 Where We Go From Here . . . . . . . . . . . . . . . . . . . . . . . . . 385
Chapter Seven
Creating OLE DB Service Providers with ATL. . . . . . . . . . . Service Providers Have the Best of Both Worlds in OLE DB . . . . . . . Creating an OLE DB Service Provider COM DLL Consumer with ATL . . Gentlemen, Start Your Keyboards! . . . . . . . . . . . . . . . . . . . Building the OLE DB Service Provider Consumer DLL . . . . . . . . . Creating an OLE DB Service Provider COM DLL Provider with ATL . . . Gentlemen, Start Your Keyboards! . . . . . . . . . . . . . . . . . . . Building the OLE DB Provider DLL . . . . . . . . . . . . . . . . . . . Creating an OLE DB Service Provider Consumer Application with MFC . Building the MFC OLE DB Consumer Application . . . . . . . . . . . Testing the OLE DB Service Provider with the MFC Consumer Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Where We Go From Here . . . . . . . . . . . . . . . . . . . . . . . . .
387 387 388 393 400 400 401 403 404 417
Creating and Using Simple OLE DB Consumers in ATL. OLE DB Consumer Templates in Action. . . . . . . . . . . . . . Creating an OLE DB Consumer COM Server with ATL . . . . . . Creating an ODBC-Compliant Database with Access . . . . . . Creating an ODBC Connection with Control Panel . . . . . . . Creating an OLE DB Provider COM DLL with ATL . . . . . . . . What the Wizard Wrought . . . . . . . . . . . . . . . . . . . Customizing the OLE DB Consumer . . . . . . . . . . . . . . Disabling Rowset Return on Database Open . . . . . . . . . . Adding OLE DB Consumer and Microsoft Agent Support . . . Adding the COM Server Code to Use the OLE DB Consumer . .
419 419 420 420 423 426 433 436 437 438 440
Chapter Eight
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Contents n
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Building the OLE DB Consumer DLL . . . . . . . . . . . . . . . Creating a Client Application for an OLE DB Consumer with MFC. Building the MFC OLE DB Consumer Application . . . . . . . . Testing the OLE DB Consumer with the MFC Application . . . . Where We Go from Here . . . . . . . . . . . . . . . . . . . . . .
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449 449 469 469 470
Chapter Nine
Creating and Using Complex OLE DB Consumers in OLE DB Consumer Templates in MFC. . . . . . . . . . . . . Creating an OLE DB Consumer MDI Application with MFC . Building the MFC OLE DB Consumer Application . . . . . Testing the MFC OLE DB Consumer Application . . . . . . Where We Go From Here . . . . . . . . . . . . . . . . . . .
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471 471 471 498 498 499
Chapter Ten
Putting OLE DB on the Internet . . . . . . . . . . . . . . . . . Using the LPK_TOOL Application to Create HTML Run-time License LPK Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Downloading the ActiveX SDK . . . . . . . . . . . . . . . . . . . . Code Signing using Authenticode™—Obtaining an SPC . . . . . . . Code Signing using Authenticode™—Digitally Signing Code . . . . Obtaining and Using ActiveX Control Pad from Microsoft . . . . . . Automatic COM
Tags/Visual Editing . . . . . . . . . Creation of HTML Layout Controls . . . . . . . . . . . . . . . . . Visual Editing of HTML Layout Controls . . . . . . . . . . . . . . ActiveX Script Wizard for HTML and ALX . . . . . . . . . . . . . Obtaining and Using File Transfer Protocol (FTP) Software to Place COM Elements on the Internet . . . . . . . . . . . . . . . . . . . Using Internet Explorer to Access COM Over the Internet and World Wide Web. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mastering COM Over the Internet . . . . . . . . . . . . . . . . . . Where We Go From Here . . . . . . . . . . . . . . . . . . . . . . . “URLProv.h”, public CComCoClass, public IDBCreateSessionImpl, public IDBInitializeImpl, public IDBPropertiesImpl, public IPersistImpl, public IInternalConnectionImpl { public: HRESULT FinalConstruct() { return FInit(); } DECLARE_REGISTRY_RESOURCEID(IDR_URLPROVIDER) BEGIN_PROPSET_MAP(CURLProviderSource) BEGIN_PROPERTY_SET(DBPROPSET_DATASOURCEINFO) PROPERTY_INFO_ENTRY(ACTIVESESSIONS) PROPERTY_INFO_ENTRY(DATASOURCEREADONLY) PROPERTY_INFO_ENTRY(BYREFACCESSORS) PROPERTY_INFO_ENTRY(OUTPUTPARAMETERAVAILABILITY) PROPERTY_INFO_ENTRY(PROVIDEROLE DBVER) PROPERTY_INFO_ENTRY(DSOTHREADMODEL) PROPERTY_INFO_ENTRY(SUPPORTEDTXNISOLEVELS) PROPERTY_INFO_ENTRY(USERNAME) END_PROPERTY_SET(DBPROPSET_DATASOURCEINFO) BEGIN_PROPERTY_SET(DBPROPSET_DBINIT) PROPERTY_INFO_ENTRY(AUTH_PASSWORD) PROPERTY_INFO_ENTRY(AUTH_PERSIST_SENSITIVE_AUTHINFO) PROPERTY_INFO_ENTRY(AUTH_USERID) PROPERTY_INFO_ENTRY(INIT_DATASOURCE) PROPERTY_INFO_ENTRY(INIT_HWND), public IAccessorImpl, public ICommandTextImpl, public ICommandPropertiesImpl, public IObjectWithSiteImpl, public IConvertTypeImpl, public IColumnsInfoImpl { public: BEGIN_COM_MAP(CURLProviderCommand) COM_INTERFACE_ENTRY(ICommand) COM_INTERFACE_ENTRY(IObjectWithSite) COM_INTERFACE_ENTRY(IAccessor) COM_INTERFACE_ENTRY(ICommandProperties) COM_INTERFACE_ENTRY2(ICommandText, ICommand) COM_INTERFACE_ENTRY(IColumnsInfo) COM_INTERFACE_ENTRY(IConvertType) END_COM_MAP() // ICommand public: HRESULT FinalConstruct() { HRESULT hr = CConvertHelper::FinalConstruct(); if (FAILED (hr)) return hr; hr = IAccessorImpl::FinalConstruct();::FInit(); } void FinalRelease() { IAccessorImpl::FinalRelease(); } HRESULT WINAPI Execute(IUnknown * pUnkOuter, REFIID riid, DBPARAMS * pParams, LONG * pcRowsAffected, IUnknown ** ppRowset); static ATLCOLUMNINFO* GetColumnInfo(CURLProviderCommand* pv, ULONG* pcInfo) { return CURLProviderWindowsFile::GetColumnInfo(pv,pcInfo); } BEGIN_PROPSET_MAP(CURLProviderCommand) BEGIN_PROPERTY_SET(DBPROPSET_ROWSET) PROPERTY_INFO_ENTRY(IAccessor) PROPERTY_INFO_ENTRY(IColumnsInfo) PROPERTY_INFO_ENTRY(IConvertType) PROPERTY_INFO_ENTRY(IRowset) PROPERTY_INFO_ENTRY(IRowsetIdentity) PROPERTY_INFO_ENTRY(IRowsetInfo) PROPERTY_INFO_ENTRY(IRowsetLocate) PROPERTY_INFO_ENTRY(BOOKMARKS) PROPERTY_INFO_ENTRY(BOOKMARKSKIPPED) PROPERTY_INFO_ENTRY(BOOKMARKTYPE) PROPERTY_INFO_ENTRY(CANFETCHBACKWARDS) PROPERTY_INFO_ENTRY(CANHOLDROWS) PROPERTY_INFO_ENTRY(CANSCROLLBACKWARDS) PROPERTY_INFO_ENTRY(LITERALBOOKMARKS) PROPERTY_INFO_ENTRY(ORDEREDBOOKMARKS) END_PROPERTY_SET(DBPROPSET_ROWSET) END_PROPSET_MAP() }; class CURLProviderRowset : public CRowsetImpl< CURLProviderRowset, CURLProviderWindowsFile, CURLProviderCommand> { public: HRESULT Execute(DBPARAMS * pParams, LONG* pcRowsAffected) { USES_CONVERSION; BOOL bFound = FALSE; HANDLE hFile; LPTSTR szDir = (m_strCommandText == _T(“”)) ? _T(“*.*”) : OLE2T(m_strCommandText); CURLProviderWindowsFile wf; hFile = FindFirstFile(szDir, &wf);, public IGetDataSourceImpl, public IOpenRowsetImpl, public ISessionPropertiesImpl, public IObjectWithSiteSessionImpl, public IDBSchemaRowsetImpl, public IDBCreateCommandImpl { public: CURLProviderSession() { } HRESULT FinalConstruct() { return FInit(); } STDMETHOD(OpenRowset)(IUnknown *pUnk, DBID *pTID, DBID *pInID, REFIID riid, ULONG cSets, DBPROPSET rgSets[], IUnknown **ppRowset) { CURLProviderRowset* pRowset; return CreateRowset(pUnk, pTID, pInID, riid, cSets, rgSets, ppRowset, pRowset); } BEGIN_PROPSET_MAP(CURLProviderSession) BEGIN_PROPERTY_SET(DBPROPSET_SESSION) PROPERTY_INFO_ENTRY(SESS_AUTOCOMMITISOLEVELS) END_PROPERTY_SET(DBPROPSET_SESSION) //@@@ bring in custom bookmark implementation @@@ #include “urlrowloc.h” //@@@ forward definitions for compiler @@@ class CURLProviderRowset; class CURLProviderCommand; //@@@ this was already here @@@ class CURLProviderWindowsFile { public: //@@@ hold the bookmark @@@ DWORD dwBookmark; //@@@ command string @@@ TCHAR szCommand[256]; //@@@ text string @@@ TCHAR szText[256]; //@@@ command string 2 @@@ TCHAR szCommand2[256]; //@@@ text 2 @@@ TCHAR szText2[256]; //@@@ override getcolumninfo for rowsets @@@ static ATLCOLUMNINFO* GetColumnInfo(CURLProviderRowset* pThis, ULONG*pcCols); //@@@ override getcolumninfo for commands @@@ static ATLCOLUMNINFO* GetColumnInfo(CURLProviderCommand* pThis, ULONG*pcCols); }; //@@@ define a new macro to allow us to create a COLUMN entry on the fly @@@ #define ADD_COLUMN_ENTRY(ulCols, name, ordinal, colSize, type, precision, scale, guid, \ dataClass, member) \ _rgColumns[ulCols].pwszName = (LPOLESTR)name; \ _rgColumns[ulCols].pTypeInfo = (ITypeInfo*)NULL; \ _rgColumns[ulCols].iOrdinal = (ULONG)ordinal; \ _rgColumns[ulCols].dwFlags = 0; \ _rgColumns[ulCols].ulColumnSize = (ULONG)colSize; \ _rgColumns[ulCols].wType = (DBTYPE)type; \ _rgColumns[ulCols].bPrecision = (BYTE)precision; \ _rgColumns[ulCols].bScale = (BYTE)scale; \ _rgColumns[ulCols].cbOffset = offsetof(dataClass, member); \ memset(&(_rgColumns[ulCols].columnid), 0, sizeof(DBID));\ _rgColumns[ulCols].columnid.uName.pwszName =(LPOLESTR)name; > class CURLProviderRowsetImpl: public CRowsetImpl > { //@@@ COM MAP for our new class (note chaining) @@@ BEGIN_COM_MAP(CURLProviderRowsetImpl) COM_INTERFACE_ENTRY(IRowsetLocate) COM_INTERFACE_ENTRY_CHAIN(_RowsetBaseClass) END_COM_MAP() //@@@ Implementation of the class method @@@ HRESULT ValidateCommandID(DBID* pTableID, DBID* pIndexID) { //@@@ call ancestor method @@@ HRESULT hr = _RowsetBaseClass::ValidateCommandID(pTableID,pIndexID); if (hr != S_OK) return hr; //@@@ if bad HR return @@@ if (pIndexID != NULL) return DB_E_NOINDEX; //@@@ abort since we don’t do indexes @@@ return S_OK; //@@@ otherwise OK @@@ } }; //@@@ note change in base template class @@@ class CURLProviderRowset : public CURLProviderRowsetImpl< CURLProviderRowset, CURLProviderWindowsFile, CURLProviderCommand> { public: class ATL_NO_VTABLE IRowsetLocateImpl : public IRowsetImpl { public: //@@@ Implement a comparison of our bookmarks @@@ STDMETHOD (Compare)(HCHAPTER hReserved, ULONG cbBookmark1, const BYTE * pBookmark1, ULONG cbBookmark2, const BYTE * pBookmark2, DBCOMPARE * pComparison) { //@@@ call our validate bookmark to be sure they’re real ones @@@ HRESULT hr = ValidateBookmark(cbBookmark1, pBookmark1); //@@@ abort if not ok @@@ if (hr != S_OK) return hr; //@@@ call our validate bookmark to be sure they’re real ones @@@ hr = ValidateBookmark(cbBookmark2, pBookmark2); //@@@ abort if not ok @@@ if (hr != S_OK) return hr; //@@@ Return based on simple number comparisons @@@ if (*pBookmark1 == *pBookmark2) *pComparison = DBCOMPARE_EQ; if (*pBookmark1 < *pBookmark2) *pComparison = DBCOMPARE_LT; if (*pBookmark1 > *pBookmark2) *pComparison = DBCOMPARE_GT; //@@@ tell COM we’re cool @@@ return S_OK; } //@@@ This is the biggie; it returns a Rowset based on the bookmark + offset @@@ STDMETHOD (GetRowsAt)(HWATCHREGION hReserved1, HCHAPTER hReserved2, ULONG cbBookmark, const BYTE * pBookmark, LONG lRowsOffset, LONG cRows, ULONG * pcRowsObtained, HROW ** prghRows) { //@@@ we need this to be thread safe @@@ T* pT = (T*)this;CreateRow((long)*rgpBookmarks[l], ulRowsObtained, &rghRows[l]) != S_OK) { //@@@ blew it @@@ bErrors = TRUE; } else { ATLCOLUMNINFO* CommonGetColInfo(IUnknown* pPropsUnk, ULONG*pcCols) { //@@@ define structure @@@ static ATLCOLUMNINFO _rgColumns[5]; //@@@ set working variable @@@ ULONG ulCols = 0; //@@@ put the IUnknown pointer into a CComQIPtr @@@ CComQIPtr<TInterface> spProps = pPropsUnk; //@@@ create a working set @@@ CDBPropIDSet set(DBPROPSET_ROWSET); //@@@ put in bookmarks property @@@ set.AddPropertyID(DBPROP_BOOKMARKS); //@@@ get a property set variable @@@ DBPROPSET* pPropSet = NULL; //@@@ set another variable @@@ ULONG ulPropSet = 0; //@@@ define HRESULT holder @@@ HRESULT hr; //@@@ if we have a valid interface pointer get its properties @@@ if (spProps) hr = spProps->GetProperties(1, &set, &ulPropSet, &pPropSet); //@@@ if we have properties @@@ if (pPropSet) {(pThis->GetUnknown(), pcCols); } //@@@ implement rowset-based column info @@@ ATLCOLUMNINFO* CURLProviderWindowsFile::GetColumnInfo(CURLProviderRowset* pThis, ULONG* pcCols) { //@@@ use internal implementation @@@ return CommonGetColInfo(pThis->GetUnknown(), pcCols); }, public IGetDataSourceImpl, public IOpenRowsetImpl, public ISessionPropertiesImpl, public IObjectWithSiteSessionImpl, public IDBSchemaRowsetImpl, public IDBCreateCommandImpl { public: CURLProviderSession() { }, public IGetDataSourceImpl, public IOpenRowsetImpl, public ISessionPropertiesImpl, public IObjectWithSiteSessionImpl, public IDBCreateCommandImpl { public: CURLProviderSession() { } HRESULT FinalConstruct() { return FInit(); } STDMETHOD(OpenRowset)(IUnknown *pUnk, DBID *pTID, DBID*pInID, REFIID riid, ULONG cSets, DBPROPSET rgSets[], IUnknown **ppRowset) { CURLProviderRowset* pRowset; return CreateRowset(pUnk, pTID, pInID, riid, cSets, rgSets, ppRowset, pRowset); } BEGIN_PROPSET_MAP(CURLProviderSession) BEGIN_PROPERTY_SET(DBPROPSET_SESSION) PROPERTY_INFO_ENTRY(SESS_AUTOCOMMITISOLEVELS) END_PROPERTY_SET(DBPROPSET_SESSION) END_PROPSET_MAP() BEGIN_COM_MAP(CURLProviderSession) COM_INTERFACE_ENTRY(IGetDataSource) //@@@ define our handler class @@@ class CProvider { public: //@@@ put in the bookmark field @@@ CBookmark<4> bookmark; //@@@ put in the four text fields @@@ TCHAR szCommand[256]; TCHAR szText[256]; TCHAR szCommand2[256]; TCHAR szText2[256]; //@@@ put in the database map @@@ BEGIN_COLUMN_MAP(CProvider) //@@@ this is a bookmark @@@ BOOKMARK_ENTRY( bookmark ); //@@@ these are string fields @@@ COLUMN_ENTRY(1, szCommand ); COLUMN_ENTRY(2, szText ); COLUMN_ENTRY(3, szCommand2 ); COLUMN_ENTRY(4, szText2 ); END_COLUMN_MAP() }; class CTestURLProvDlgAutoProxy; ///////////////////////////////////////////////////////////////////////////// // CTestURLProvDlg dialog class CTestURLProvDlg : public CDialog { DECLARE_DYNAMIC(CTestURLProvDlg); friend class CTestURLProvDlgAutoProxy; // Construction #ifdef _DEBUG #define new DEBUG_NEW #undef THIS_FILE static char THIS_FILE[] = __FILE__; #endif ///////////////////////////////////////////////////////////////////////////// // CAboutDlg dialog used for App About class CAboutDlg : public CDialog { public: CAboutDlg(); // Dialog Data //{{AFX_DATA(CAboutDlg) enum { IDD = IDD_ABOUTBOX }; > table; 232. //@@@ define our datasource variable @@@ 233. CDataSource source; 234. //@@@ define our session variable @@@ 235. CSession session; 236. //@@@ get the OLE DB provider via COM technique @@@ 237. if (source.Open(“URLProv.URLProvider.1",NULL,NULL,NULL,NULL) !=S_OK) 238. { 239. //@@@ signal error to user @@@ 240. AfxMessageBox( “Can’t contact URLProv Server!” ); 241. //@@@ leave @@@ 242. return; 243. } 244. //@@@ open the data source object from our provider @@@ 245. if (session.Open( source ) != S_OK) 246. { 247. //@@@ signal error to user @@@ 248. AfxMessageBox( “Can’t open URLProv data source!” ); 249. //@@@ leave @@@ 250. return; 251. } 252. //@@@ create a property holder @@@ 253. CDBPropSet propset(DBPROPSET_ROWSET); 254. //@@@ tell it we support bookmarks @@@ 255. propset.AddProperty(DBPROP_IRowsetLocate, true); 256. //@@@ try to open the URLS.TXT database (created later) @@@ 257. if (table.Open(session, _T(“c:\\urls.txt”),&propset) != S_OK) 258. { 259. //@@@ signal error to user @@@ 260. AfxMessageBox( “Can’t open URLS.TXT database!” ); 261. //@@@ leave @@@ 262. return; > { public: HRESULT Open() { HRESULT hr; hr = OpenDataSource(); if (FAILED(hr)) return hr; return OpenRowset(); } HRESULT OpenDataSource() { HRESULT hr; CDataSource db; CDBPropSet dbinit(DBPROPSET_DBINIT); dbinit.AddProperty( DBPROP_AUTH_PERSIST_SENSITIVE_AUTHINFO, false); dbinit.AddProperty(DBPROP_AUTH_USERID, OLESTR(“Admin”)); dbinit.AddProperty(DBPROP_INIT_DATASOURCE, OLESTR(“CheckingAccount”)); dbinit.AddProperty(DBPROP_INIT_MODE, (long)1); dbinit.AddProperty(DBPROP_INIT_PROMPT, (short)4); dbinit.AddProperty(DBPROP_INIT_LCID, (long)1033); hr = db.Open(_T(“MSDASQL”), &dbinit); if (FAILED(hr)) return hr; >::Open(m_session); } CSession m_session; }; #endif // __CHECKINGACCOUNT_H_, public CComCoClass, public ISupportErrorInfo, public IDispatchImpl { { public: //@@@ We must implement this because we’re using bookmarks @@@ virtual DBSTATUS GetDBStatus(CSimpleRow* , HACCESSOR) { //@@@ we don’t have a status for the database @@@ return DBSTATUS_S_ISNULL; } HRESULT Execute(DBPARAMS * pParams, LONG* pcRowsAffected) { //@@@ macros @@@ USES_CONVERSION; //@@@ critical section @@@ //@@@ define our handler class @@@ class CProvider { public: //@@@ put in the bookmark field @@@ CBookmark<4> bookmark; //@@@ put in the four text fields @@@ TCHAR szAccountName[256]; TCHAR szBackupAccount[256]; TCHAR szAccountNumber[256]; TCHAR szAccountBalance[256]; //@@@ put in the database map @@@ BEGIN_COLUMN_MAP(CProvider) //@@@ this is a bookmark @@@ BOOKMARK_ENTRY( bookmark ); //@@@ these are string fields @@@ COLUMN_ENTRY(1, szAccountName ); COLUMN_ENTRY(2, szBackupAccount ); > table; 164. //@@@ define our datasource variable @@@ 165. CDataSource source; 166. //@@@ define our session variable @@@ 167. CSession session; 168. //@@@ get the OLE DB provider via COM technique @@@ 169. if (source.Open(“URLProv.URLProvider.1",NULL,NULL,NULL,NULL) 170. !=S_OK) 171. { 172. //@@@ signal error to user @@@ 173. AfxMessageBox( “Can’t contact URLProv Server!” ); 174. //@@@ leave @@@ 175. return; 176. } 177. //@@@ open the data source object from our provider @@@ 178. if (session.Open( source ) != S_OK) 179. { 180. //@@@ signal error to user @@@ 181. AfxMessageBox( “Can’t open URLProv data source!” ); 182. //@@@ leave @@@ 183. return; 184. } 185. //@@@ create a property holder @@@ 186. CDBPropSet propset(DBPROPSET_ROWSET); 187. //@@@ tell it we support bookmarks @@@ 188. propset.AddProperty(DBPROP_IRowsetLocate, true); 189. //@@@ we need to send the lookup key as a string @@@ 190. TCHAR szHolder[256]; 191. //@@@ so put it into a TCHAR array @@@ 192. wsprintf( szHolder,"%ld",m_LookupKey); 193. //@@@ then shove it into a CString to be safe @@@ 194. CString strHolder(szHolder); 195. //@@@ try to open the database @@@ 196. if (table.Open(session, strHolder ,&propset) != S_OK) 197. { > { public: HRESULT Open() { HRESULT hr; hr = OpenDataSource(); if (FAILED(hr)) return hr; return OpenRowset(); }>::Open(m_session, NULL, &propset); } CSession m_session; }; #endif // __INSTRUCTIONS_H_ > { public: HRESULT Open() { HRESULT hr; hr = OpenDataSource(); if (FAILED(hr)) return hr; return OpenRowset(); } > { public: HRESULT Open() { HRESULT hr; hr = OpenDataSource(); if (FAILED(hr)) return hr; return hr;//@@@ return OpenRowset(); disable open and return hr }, public CComCoClass, public ISupportErrorInfo, public IDispatchImpl { public: CAgentcontroller() { } HRESULT FinalConstruct(); void FinalRelease(); DECLARE_REGISTRY_RESOURCEID(IDR_AGENTCONTROLLER) DECLARE_PROTECT_FINAL_CONSTRUCT() BEGIN_COM_MAP(CAgentcontroller) COM_INTERFACE_ENTRY(IAgentcontroller) pdCharacter; //@@@ get the MSAgent ActiveX control @@@ hr = m_pAgent.CreateInstance(__uuidof(Agentserver)); //@@@ inform user if fail @@@ if (!SUCCEEDED(hr)) { return Error(_T(“Unable To Contact Microsoft Agent control!”)); } //@@@ get the defined character’s ID values @@@ hr = m_pAgent->Load(AGENT_CHARACTER,&lCharID,&m_lRequestID); //@@@ inform user if fail @@@ if (!SUCCEEDED(hr)) { return Error(_T(“Unable To Contact Microsoft Agent control!”)); } //@@@ get the designated character @@@ hr = m_pAgent->GetCharacter(lCharID,&pdCharacter); //@@@ inform user if fail @@@ tags for COM components, including visual editing of the component desired, creation of the powerful new HTML Layout control layout files (called ALX Figure 10-28 but still HTML-based), visual ActiveX Conediting and insertion of HTML trol Pad’s initial user Layouts into HTML pages, and interface ActiveX scripting automation for both HTML pages and HTML Layouts. Each of these areas is vital to effective use of COM components over the Internet, and is explained below. Tags/Visual Editing Figure 10-29 shows the menu used to insert an ActiveX control into an HTML page. Selecting it causes the Control Pad to search the Registry for the computer and produce the dialog box shown in Figure 10-30, which lists all the available COM components on the host machine. Since this is a design activity, those controls that require license keys will not work unless the key is installed on the host computer. tag works), be prepared for a significant delay while the Control Pad convinces OLE to let it have the control; the less RAM and the more ActiveX controls you have on your system, the longer this will take (on my machine it’s about five minutes!). Figure 10-31 shows the various parts of the ActiveX Control Pad Editor interface. The window marked “A” is the main visual editor pane. It allows you to size the control and observe its visual characteristics; however, it does not keep position information (unlike the HTML Layout control discussed below), so moving the control away from the top of the editor window has no net effect. The window marked “B” is the core of AXC editing in the Control Pad. It contains all the available properties for the control, and either accepts a value for them via typing into the upper text control (next to the Apply button) or supplies a drop-down list of values. Sometimes a custom editor tag into the HTML file at the position of the cursor when the Edit menu option was invoked. This is shown in Figure 10-32, where I have accidentally placed the tag in an invalid position, inside the block. (I moved it after discovering this...:)). Notice the tags written after the main tag; these are where the custom values set in the ActiveX Editor are stored so the browser or other application can re-create them. Some Figure 10-32 defective controls don’t corAn rectly store their visual editing results this way, which will tag inserted result in those settings being Into the lost when the control is HTML by re-created in the target ActiveX Conenvironment. trol Pad tag will then be written into the HTML to show the Layout at that point in the HTML stream. Unfortunately, there is no way at present to position two Layout controls effectively on either the same HTML page or a single Layout. In the case of multiple Layout controls on the same HTML page, they simply get treated like any other object and drawn in the sequence found in the HTML. The Layout control itself will not permit another copy of itself to be placed on it, to prevent stack explosions and other fun recursive catastrophes. tags, 514-515 Object Wizard, see ATL Object Wizard OCX controls, 3-4, 15 OLE, 2-4 OLE 1.0, 2-4 OLE 2, 2-4 OLE Automation, 3, 10, 12-13 OLE DB, 4, 53, 235 and the Internet, 501 consumer templates, 419 keywords, 80-83 OLE DB projects creating client application with MFC, 449-469 creating consumer application with MFC, 368-383 creating consumer COM server with ATL, 420-426 creating consumer MDI application with MFC, 471-498 creating provider COM DLL with ATL, 326-368, 426-449 creating service provider COM DLL consumer with ATL, 388-400 creating service provider COM DLL provider with ATL, 400-403 creating service provider consumer with MFC, 404-417 testing consumer, 469-470 testing consumer application, 498-499 testing provider, 384-385 testing service provider, 417 P Parameter object, 304 properties, 304-308 
