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.Although it s tempting to design every application with a the sky s the limit approach so that it can accommodate the full spectrum of busi-ness environments, you need to find the right balance between maximum flexibilityand simplicity.When selecting the database engine that is most appropriate for your application,consider these four criteria:&' Simplicity&' Data integrity&' Number of Users&' Volume of DataIn the simplicity category, Jet gets the score.As the default database in Access 2002,creating a Jet database is much easier than creating one for SQL Server 2000 DesktopEngine.It is also the most compatible with previous versions of Access.AlthoughAccess provides built-in security administration, Jet databases don t require security(user IDs and passwords).SQL Server 2000 Desktop Engine does require security anduses the Windows NT security model.The memory and hard drive space require-ments for Jet databases are low as compared to SQL Server 2000 Desktop Engine.TipYou can always upsize a Jet database to SQL Server later on using the UpsizingWizard.You may need to make some modifications to the application, however.When considering data integrity, SQL Server 2000 Desktop Engine is the most reliablechoice.SQL Server 2000 Desktop Engine includes the same data integrity technologythat is provided in SQL Server 2000.All changes that you make to the database arelogged to a transaction file.In the event of a database disaster a hardware failure orpower interruption, for example the database can repair itself using the log file.With Jet, however, this kind of disastrous event can permanently corrupt thedatabase.As anyone who has ever tried to repair an Access database knows, a reli-able backup strategy is a must.For some mission-critical applications, though, restor-ing from yesterday s backup can result in a major business interruption.For thosetypes of applications, SQL Server 2000 Desktop Engine is the best option.NoteWhen addressing the limitations of SQL Server 2000 Desktop Engine, rememberthat it is 100 percent compatible with SQL Server 2000.Both Jet and SQL Server 2000 Desktop Engine are designed for the single work-station or small workgroup.Generally, SQL Server 2000 Desktop Engine can handlethe same number of simultaneous users as Jet.SQL Server 2000 Desktop Engine, 3596-X ch33.F 5/30/01 11:48 AM Page 1116Part VI &' Access and the External World1116however, has a limit of five active simultaneous query batches.That is, the databaseengine can process up to five queries at one time.SQL Server will queue any subse-quent queries until one or more of the previous five query batches completes.Despite this limitation, SQL Server 2000 Desktop Engine, as a client/server databaseengine, has the performance advantage over Jet even in a small workgroup situation.SQL Server 2000 Desktop Engine processes queries on the server and moves onlythe resulting data to the client workstation.Jet, on the other hand, must move thedata to the client so that the client workstation can process the query.Both Jet and SQL Server 2000 Desktop Engine have a maximum database size of 2GB.For applications that accumulate a large volume of data over a long period of time,consider including an archive/purge utility in the application.For many business situ-ations, only a relatively small volume of data needs to be active at any point in time.If you have determined that SQL Server 2000 Desktop Engine is the right databaseengine to utilize in your database application, you are ready to begin working withthis new and powerful feature of Access 2002.Table 33-1 compares the capabilities of SQL Server and Jet.The table comes fromthe Microsoft Access 2000 Data Engine Options whitepaper and is reprinted withpermission from Microsoft.Table 33-1Comparison of SQL Server/MSDE and JetRequirement SQL Server Microsoft Access (Jet) (Use MSDE ifThese Are Future Requirements)Scalability SMP support No SMP supportVirtually unlimited number Maximum of 255 usersof concurrent usersTerabyte levels of data 2 GB of dataTransaction logging No transaction loggingBusiness Critical 7X24 support and QFE No 7X24 support or QFEPoint-in-time recovery Recoverable to last backupGuaranteed transaction No transaction loggingintegrityBuilt-in fault tolerance No integrated security with Windows NTSecurity integrated withWindows NTRapid Application Access is UI for bothengines and Prototypingoffers WYSIWIG databasetools and built-in forms generation 3596-X ch33.F 5/30/01 11:49 AM Page 1117Chapter 33 &' Moving from Jet to the SQL Server 2000 Desktop Engine1117Installing SQL Server 2000 Desktop EngineSQL Server 2000 Desktop Engine doesn t install automatically when you installOffice 2002.It is provided as a separate installation process included on the Office2002 CD-ROM.Hardware requirementsChances are, if you are successfully running Office 2002 on your personal computer,your hardware meets the minimum requirements for SQL Server 2000 DesktopEngine.For Windows 2000 computers, SQL Server 2000 Desktop Engine requires 64MB ofRAM.For other operation systems, 32MB of RAM is required.SQL Server 2000Desktop Engine requires approximately 45MB of hard drive space for a typicalinstallation 25MB for program files and 20MB for data files.Optionally, you canstore the program files and data files on separate drives.Remember that you needadditional space for your database files.TipIn reality, you should have a minimum of 128MB on any computer system runningMicrosoft business software purchased in 2001 or later.NoteMSDE, Microsoft Data Engine, is the previous version of Microsoft SQL Server 2000Desktop Engine.MSDE is compatible with SQL Server Version 7.While SQL Server2000 Desktop Engine provides some additional features, the two desktop versionsare very similar.For the purposes of this discussion, any of the concepts thatapplied to MSDE certainly apply to SQL Server 2000 Desktop Engine.Software requirementsSQL Server 2000 Desktop Engine requires that Microsoft Windows 98, Windows MEor later, Windows NT 4.0 or later, or Windows 2000 or later be installed on yourcomputer.SQL Server 2000 Desktop Engine does not run on OS/2, Windows 95, orWindows 3.1.Running the SQL Server 2000 Desktop EngineInstallation ProgramTo install SQL Server 2000 Desktop Engine, insert the Office 2002 CD-ROM into yourCD-ROM drive and select Run from the Start menu.In the Run box, typeD:\MSDE2000\Setup.exe (or use whatever letter corresponds to the drive contain-ing your installation CD-ROM).Click OK to begin the installation. 3596-X ch33.F 5/30/01 11:49 AM Page 1118Part VI &' Access and the External World1118CautionIf you have installed MSDE, the previous version of SQL Server 2000 DesktopEngine, you should uninstall it before installing SQL Server 2000 Desktop Engine [ Pobierz całość w formacie PDF ]
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.Although it s tempting to design every application with a the sky s the limit approach so that it can accommodate the full spectrum of busi-ness environments, you need to find the right balance between maximum flexibilityand simplicity.When selecting the database engine that is most appropriate for your application,consider these four criteria:&' Simplicity&' Data integrity&' Number of Users&' Volume of DataIn the simplicity category, Jet gets the score.As the default database in Access 2002,creating a Jet database is much easier than creating one for SQL Server 2000 DesktopEngine.It is also the most compatible with previous versions of Access.AlthoughAccess provides built-in security administration, Jet databases don t require security(user IDs and passwords).SQL Server 2000 Desktop Engine does require security anduses the Windows NT security model.The memory and hard drive space require-ments for Jet databases are low as compared to SQL Server 2000 Desktop Engine.TipYou can always upsize a Jet database to SQL Server later on using the UpsizingWizard.You may need to make some modifications to the application, however.When considering data integrity, SQL Server 2000 Desktop Engine is the most reliablechoice.SQL Server 2000 Desktop Engine includes the same data integrity technologythat is provided in SQL Server 2000.All changes that you make to the database arelogged to a transaction file.In the event of a database disaster a hardware failure orpower interruption, for example the database can repair itself using the log file.With Jet, however, this kind of disastrous event can permanently corrupt thedatabase.As anyone who has ever tried to repair an Access database knows, a reli-able backup strategy is a must.For some mission-critical applications, though, restor-ing from yesterday s backup can result in a major business interruption.For thosetypes of applications, SQL Server 2000 Desktop Engine is the best option.NoteWhen addressing the limitations of SQL Server 2000 Desktop Engine, rememberthat it is 100 percent compatible with SQL Server 2000.Both Jet and SQL Server 2000 Desktop Engine are designed for the single work-station or small workgroup.Generally, SQL Server 2000 Desktop Engine can handlethe same number of simultaneous users as Jet.SQL Server 2000 Desktop Engine, 3596-X ch33.F 5/30/01 11:48 AM Page 1116Part VI &' Access and the External World1116however, has a limit of five active simultaneous query batches.That is, the databaseengine can process up to five queries at one time.SQL Server will queue any subse-quent queries until one or more of the previous five query batches completes.Despite this limitation, SQL Server 2000 Desktop Engine, as a client/server databaseengine, has the performance advantage over Jet even in a small workgroup situation.SQL Server 2000 Desktop Engine processes queries on the server and moves onlythe resulting data to the client workstation.Jet, on the other hand, must move thedata to the client so that the client workstation can process the query.Both Jet and SQL Server 2000 Desktop Engine have a maximum database size of 2GB.For applications that accumulate a large volume of data over a long period of time,consider including an archive/purge utility in the application.For many business situ-ations, only a relatively small volume of data needs to be active at any point in time.If you have determined that SQL Server 2000 Desktop Engine is the right databaseengine to utilize in your database application, you are ready to begin working withthis new and powerful feature of Access 2002.Table 33-1 compares the capabilities of SQL Server and Jet.The table comes fromthe Microsoft Access 2000 Data Engine Options whitepaper and is reprinted withpermission from Microsoft.Table 33-1Comparison of SQL Server/MSDE and JetRequirement SQL Server Microsoft Access (Jet) (Use MSDE ifThese Are Future Requirements)Scalability SMP support No SMP supportVirtually unlimited number Maximum of 255 usersof concurrent usersTerabyte levels of data 2 GB of dataTransaction logging No transaction loggingBusiness Critical 7X24 support and QFE No 7X24 support or QFEPoint-in-time recovery Recoverable to last backupGuaranteed transaction No transaction loggingintegrityBuilt-in fault tolerance No integrated security with Windows NTSecurity integrated withWindows NTRapid Application Access is UI for bothengines and Prototypingoffers WYSIWIG databasetools and built-in forms generation 3596-X ch33.F 5/30/01 11:49 AM Page 1117Chapter 33 &' Moving from Jet to the SQL Server 2000 Desktop Engine1117Installing SQL Server 2000 Desktop EngineSQL Server 2000 Desktop Engine doesn t install automatically when you installOffice 2002.It is provided as a separate installation process included on the Office2002 CD-ROM.Hardware requirementsChances are, if you are successfully running Office 2002 on your personal computer,your hardware meets the minimum requirements for SQL Server 2000 DesktopEngine.For Windows 2000 computers, SQL Server 2000 Desktop Engine requires 64MB ofRAM.For other operation systems, 32MB of RAM is required.SQL Server 2000Desktop Engine requires approximately 45MB of hard drive space for a typicalinstallation 25MB for program files and 20MB for data files.Optionally, you canstore the program files and data files on separate drives.Remember that you needadditional space for your database files.TipIn reality, you should have a minimum of 128MB on any computer system runningMicrosoft business software purchased in 2001 or later.NoteMSDE, Microsoft Data Engine, is the previous version of Microsoft SQL Server 2000Desktop Engine.MSDE is compatible with SQL Server Version 7.While SQL Server2000 Desktop Engine provides some additional features, the two desktop versionsare very similar.For the purposes of this discussion, any of the concepts thatapplied to MSDE certainly apply to SQL Server 2000 Desktop Engine.Software requirementsSQL Server 2000 Desktop Engine requires that Microsoft Windows 98, Windows MEor later, Windows NT 4.0 or later, or Windows 2000 or later be installed on yourcomputer.SQL Server 2000 Desktop Engine does not run on OS/2, Windows 95, orWindows 3.1.Running the SQL Server 2000 Desktop EngineInstallation ProgramTo install SQL Server 2000 Desktop Engine, insert the Office 2002 CD-ROM into yourCD-ROM drive and select Run from the Start menu.In the Run box, typeD:\MSDE2000\Setup.exe (or use whatever letter corresponds to the drive contain-ing your installation CD-ROM).Click OK to begin the installation. 3596-X ch33.F 5/30/01 11:49 AM Page 1118Part VI &' Access and the External World1118CautionIf you have installed MSDE, the previous version of SQL Server 2000 DesktopEngine, you should uninstall it before installing SQL Server 2000 Desktop Engine [ Pobierz całość w formacie PDF ]