Analyzing Access 97's Enhancements and Changes
Microsoft is determined to move all users of 16-bit Windows 3.1+ to 32-bit Windows 95 or, better yet, Windows NT Workstation 4.0. During a Microsoft briefing for security analysts, Bill Gates described the software market as an "annuity business," which explains (at least in part) the almost-annual updates to Microsoft Office and, thus, to Microsoft Access. Many large organizations, especially those with thousands of PCs, decided not to pay the 1995-96 annuity premium for the Windows 95 upgrade, opting to stay with "tried-and-true" Windows 3.1+ and Microsoft Office 4.x.
PC vendors installed Windows 95 on about 80 percent of all new PCs delivered after August 1995, but sales of Windows 95 and its 32-bit applications to corporations and other large organizations didn't meet distributors' early expectations. The reluctance to upgrade existing PCs stemmed from the cost of adding 8M or more of RAM and large disk drives to accommodate Windows 95's and 32-bit applications' bigger footprints. Many purchasers of new PCs required suppliers to install Windows for Workgroups 3.11, so as to avoid the need to provide help desk support for two different operating systems.
Corporate adoption of Windows 95 and Windows NT 4.0 accelerated in 1997, dramatically changing the ratio of application sales in favor of 32-bit versions. Web-based corporate intranets provide much of the impetus for moving to 32-bit Windows operating systems; today's 32-bit Web browsers offer better performance and more features than the 16-bit variety. Rapidly declining prices of Pentium-based PCs and dynamic RAM during 1996 and early 1997 reduced the cost of upgrading to "Designed for Windows 95" PCs. Replacing 80486 and slower processors with Pentium, Pentium Pro, and Pentium II chips disguises the slower operating speed of large 32-bit Windows applications. A continuing trend toward the use of laptop PCs in the corporate environment makes the Plug and Play, energy management, and PCMCIA card support features of Windows 95 compelling reasons for upgrading to 32 bits. By mid-1997, Microsoft claimed sales of more than 10 million Office 97 licenses, the majority of which were for the Professional version.
Major Access 97 Enhancements
Continuing enhancement of the members of the 32-bit Office software suite also accelerates the trend toward 32-bit Windows operating systems. Access 97 is an incremental upgrade to Access 95, not the major upgrade represented by the transition from Access 2.0 to Access 95. Following are Access 97's most significant new features:
Internet features are the primary addition to Access 97, as well as to other members of Office 97. You can export datasheets to static or active HTML pages for the World Wide Web, publish multipage reports in a series of static Web pages, and use the Publish to the Web Wizard to create the HTML 3.2 equivalent of Access forms (see Figure 1.1). Access now sports an HTML field data type to store Web URLs (Uniform Resource Locators), as well as pointers to content stored within Office documents. You also can synchronize Briefcase replicas over the Internet. Chapters 16, 17, and 18 show you how to take advantage of Access 97's new features for private intranets and the public Internet.
Figure 1.1. The second dialog of the Publish to the Web Wizard.
Performance is enhanced compared to Access 95, which many Access 95 users might consider damnation by faint praise. The major complaint among Access developers was that most Access 95 applications ran slower than their Access 2.0 counterparts. Forms that don't include event-handling code load faster. Microsoft has fine-tuned the Jet 3.5 database engine and Access 97 for increased operating speed. The new lightweight ActiveX controls also are faster than Access 95's OLE Controls.
CommandBar objects let you customize menus and create toolbars. You can show or hide, customize, resize, dock, or move the toolbars. You also use CommandBar objects to create custom pop-up menus. You program CommandBar objects with VBA, eliminating the need for the awkward menu macros of Access 95 and prior versions.
▸▸ See Replacing AddMenu Macro Actions with CommandBar Objects
The Tab control is an Access native control, included in the toolbox, instead of the add-on 32-bit OLE Control for Access 95. Tab controls let you create forms that emulate the tabbed dialogs of Windows 95 property sheets. Figure 1.2 shows the tabbed SolutionsHyperForm of the Solutions.mdb database included with Office 97.
▸▸ See Creating a Tab Control
Figure 1.2. The Solutions example database's SolutionsHyperForm, which uses Access 97's built-in Tab control.
Jet 3.5 lets you limit number of records returned by queries. Limiting the size of query result sets prevents runaway queries, which return thousands of rows when users specify inappropriate criteria. All Office 97 members use the Jet 3.5 Data Access Object for database connectivity.
Open Database Connectivity (ODBC) 3.0 brings you the new tabbed 32-bit ODBC Data Source Administrator control panel tool shown in Figure 1.3. You now can create system-wide data sources (System DSN page) that aren't specific to a single user (User DSN page). You also can share Datasource.dsn files (File DSN page) that specify ODBC connections to simplify deployment of Access client/server front ends. ODBC 3.0 provides enhanced tracing capability (Tracing page) and displays of the version numbers of all ODBC-related files (ODBC Drivers and About pages). You also can create ODBC 3.0 data sources from within Access 97. ODBC 3.0 is required in order to use Microsoft's OLE DB technology and ActiveX Data Objects with Internet Information Server 3.0's Active Server Pages (ASPs).
▸▸ See Using the ODBC Data Source Administrator to Create a SQL Server Data Source
▸▸ See Creating a File Data Source Within Access 97
Figure 1.3. ODBC 3.0's enhanced ODBC Data Source Administrator.
Note
Internet Information Server 4.0 includes ODBC 3.5, a relatively minor upgrade to ODBC 3.0. ODBC 3.5's most evident new feature is a Wizard for creating SQL Server 6.5 ODBC data sources.
ODBCDirect speeds client/server queries by using the Remote Data Object (RDO) of Visual Basic's Enterprise Edition to bypass the Jet 3.5 database engine. Of primary interest to Access developers is ODBCDirect's ability to execute asynchronous queries and batch updates of changes to Recordset objects.
Microsoft Graph 8.0 represents a considerable improvement over version 5.0 included with Access 95. Graph 8.0 includes new chart types, such as Bubble, Cylinder, and Cone. Graph 8.0 is a 32-bit OLE applet used by all Office 97 members. Figure 1.4 shows most of the graph and chart types provided by Graph 8.0.
▸▸ See Using the Chart Wizard to Create an Unlinked Graph
Figure 1.4. Some of the graph and chart types you can create with Microsoft Graph 8.0.
Visual Basic for Applications 5.0 now is common to the Office 97 product line, including Word 97 but not including Outlook. (Outlook uses Visual Basic, Scripting Edition, a subset of VBA 5.0 better known as VBScript, as its programming language.) Visual Basic 5.0 also uses VBA 5.0, which accounts for VBA's version number being 5.0, not 8.0. Access 97 extensively uses the Access-only DoCmd object, so this book uses the term Access VBA to identify code that relies on Access-specific objects.
▸▸ See Introducing Access VBA
The .mde file format lets you save .mdb files without including readable VBA source code. This way, developers can protect their intellectual property when creating Access 97 applications, libraries, and wizards.
Auto List Members in the Module window displays a list of possible values for statement completion. Typing the first letter of an object type, property, or method automatically searches the list (see Figure 1.5). Auto Quick Info provides VBA syntax information. Auto Parameter provides parameter information for object methods. You can turn these features on and off with menu commands.
Programmatic references to object libraries is an important new feature for Access developers. Access 97 provides the References collection, which you can manipulate with VBA 5.0.
Figure 1.5. The automatic Quick Info feature listing possible objects for completion of a variable declaration statement.
Improvements to the Debug window include a change from a modal dialog to a non-modal window. You also can specify that the Debug window remain on top of other windows. The Debug window's Expression pane shows the current value of variables during execution of VBA code (see Figure 1.6).
▸▸ See Using the Debug Window
Figure 1.6. Obtaining the value of a variable in the Debug window opened by a breakpoint placed in VBA code.
A redesigned Object Browser is shared by all Office 97 members (see Figure 1.7). You can display all the objects that you've created references to, only the member objects of a specific reference, or search for an object by name. When you select a member object, such as a property or method, the syntax for the member object automatically appears in the lower pane of the Object Browser. Clicking the Help button opens the help topic for the object or member object, if a help topic is available.
▸▸ See Examining Project Class Module Members in the Object Browser
Figure 1.7. Object Browser displaying objects in the Northwind project (Northwind.mdb).
To navigate through Microsoft's entire list of new Access 97 features, use Explorer to open the Acnew80.hlp file or choose Contents and Index from Access 97's Help menu; then click the Welcome to Microsoft Access 97 What's New topic. Each individual help window includes what's new in both Access 97 and Access 95.
Important Access 97 Changes
Users of prior versions of Access upgrading to Access 97 are interested primarily in changes. Following are the principal differences between Access 95 and Access 97 that don't qualify as enhancements:
The Jet .mdb file structure has changed for the fourth time. Access 97's Jet 3.5 .mdb file structure isn't backwardly compatible with Access 95 or 2.0. You can open an Access 1.x, 2.0, or 95 database in Access 97, but you can't open an Access 97 database in earlier versions of Access. You can't change in Access 97 the properties of database objects created with prior versions of Access; you must convert the file to Jet 3.5 format to make design-mode changes. Fortunately, you can link (the new term for attach) Access 1.x, 2.0, or 95 tables to Access 97 applications. Thus, you can accommodate simultaneous links to tables in Access 1.x, 2.0, and 95 .mdb files by database front-end applications created with Access 97 and its predecessors.
▸▸ See Using Access 2.0 Application .mdb Files with Access 97
Access executable and support files are installed in a common default Office folder. They can be found in Program FilesMicrosoft OfficeOffice with the other Office 97 members. Example files, such as Northwind.mdb, are stored in Program Files Microsoft OfficeOfficeSamples.
System.mdw has moved. Setup now installs the workgroup information file (previously called the system file or system database) in the WindowsSystem folder of Windows 95 or the WinntSystem32 folder of Windows NT 3.51+. Previously, System.mda (Access 2.0 and earlier) or System.mdw (Access 95+) was installed in the same folder as Msaccess.exe. According to Microsoft, the relocation of System.mdw is necessary to support the run-from-network and run-from-CD-ROM versions of Office 97.
Wrkgadm.exe has moved. Like System.mdw, the Workgroup Administrator application has moved from the ...Access folder of prior versions to the Windows System folder of Windows 95 or the WinntSystem32 folder of Windows NT 3.51+. Setup doesn't create a Start menu choice for Wrkgadm.exe; you should create a desktop shortcut to Wrkgadm.exe to expedite connection to multiuser Access applications.
Macro support is for backward compatibility only. Now that all Office 97 members (except Outlook) support VBA 5.0, Microsoft wants you to substitute VBA event-handling code for macros. Access 95 required you to write custom menu macros; you program CommandBar objects to create custom menus and toolbars with Access 97. There's no assurance that future versions of Access will support macros, so Access macros are obsolescent, at best.
Some files you need are part of the Office 97 ValuPack. For example, the help files for programming Graph 8.0 are located in the ValuPackMoreHelp folder of the Office 97 CD-ROM. You must copy the .hlp (help) and .cnt (content) files you need to your ... Office folder, and then delete the existing .gid file to create a new search index for the help file.
Class modules replace code-behind-forms (CBF) modules of Access 2.0 and Access 95. Class modules, which originated in Visual Basic 4.0, also let you write VBA code in the form of reusable components, each with its own set of custom properties and methods.
Many of these changes are the result of Microsoft's desire to fully integrate Access with the other members of the Office software suite. Microsoft's Office program management group is responsible for assuring "look and feel" consistency across all members of Office 97 and its successors.