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Introduction

Introduction

Microsoft Access 97, Version 8.0 (called Access 97 in this book), is a powerful and robust 32-bit relational database management system (RDBMS) for creating desktop and client/server database applications that run under Windows 95+ and Windows NT 3.51+. As a component of the Professional and Developer editions of the Microsoft Office 97 suite, Access 97 has an upgraded user interface that's consistent with Microsoft Excel 97 and Word 97, as well as Windows 95 common controls, such as an Explorer-style Database window and common file open and save dialogs.

Like all members of Office 97, Access 97 offers a variety of new Internet-related features for creating HTML documents used by the World Wide Web. The upgraded Jet 3.5 database engine speeds queries against client/server databases with ODBCDirect. Aside from improved speed, Internet enhancements, and ODBCDirect, Access 97 doesn't vary dramatically from Access 95. Improved performance was Microsoft's first priority for the developers of Access 97, because Access 95 had gained a well-deserved reputation for slow operation. Ease of use was the second priority; Access 97 includes many new or improved wizards and other aids designed for first-time database users.

If you're a new Access user, a brief history of Microsoft Access is useful to put Access 97 in perspective. Version 1.0 of Access revolutionized the Windows database market and achieved a new record for sales of a Windows application—Microsoft Corporation received orders for more than 750,000 copies of Access 1.0 between its release data in mid-November 1992 and January 31, 1993. Access 1.1, introduced in May 1993, solved some of the shortcomings in Access 1.0, and the Access 1.1 Distribution Kit (ADK) allowed developers to release royalty-free, runtime versions of their Access applications.

Access 2.0, released about a year after Access 1.1, added OLE 2.0 client capability and was the first Microsoft application to use 16-bit OLE Controls, prepackaged objects that extended the already rich set of control objects of Access. Access 2.0 was a member of the Professional Edition of the phenomenally successful Microsoft Office 4.x software suite. Office 4.x gained almost 80 percent of the Windows productivity software suite market. By far, most of Access 2.0's multimillion-copy sales resulted from the product's inclusion in Office 4.x Professional Edition.

Microsoft introduced Access 95, the first 32-bit version of Access, in late 1995 as a component of Microsoft Office 95 Professional Edition. Access 95 adopted VBA as its programming language and was the first multithreaded member of the Office suite. The success of Office 95, and thus Access 95, depended on adoption of Windows 95—and, to a lesser extent, Windows NT Workstation 3.51 and 4.0—by major corporate accounts. Windows 95 was installed on more than 80 percent of all new PCs shipped, but the rate of migration from 16-bit to 32-bit Windows on existing PCs turned out to be much slower than anticipated by Microsoft and other software publishers. In many cases, moving to Access 95 required additional RAM. Even with 16M of RAM, however, most 32-bit Access applications ran slower than their 16-bit predecessors in 8M of RAM. Fortunately, the trend toward upgrading 80486DX PCs to 133-MHz and faster Pentium models accelerated during 1996, and 16M became the standard for all but the most parsimonious organizations. Use of Access 95 began to really take off in mid-1996. By the fall of 1996, Microsoft announced that it had sold a cumulative total of 10 million copies of Access. Paul Maritz, Microsoft's group vice president for platforms and applications, said in late July 1997 that Microsoft shipped more than 25 million Microsoft Office licenses during the fiscal year ending in June 1997, and that about 65 million people use Microsoft Office worldwide.

A primary reason for Access's success is that it duplicates on the PC desktop many of the features of client/server relational database systems, also called SQL databases. Client/server RDBMSs are leading the way in transferring database applications from minicomputers and mainframes to networked PCs—a process called downsizing. Despite Access's power, this desktop RDBMS is easy for non-programmers to use. Buttons on upgraded multiple toolbars, which are almost identical across the Office 97 members, offer shortcuts for menu commands. An extensive collection of wizards and add-ins handle most of the mundane chores involved in creating and modifying tables, queries, forms, graphs, and reports. Builders aid you in creating complex controls on forms and reports, as well as in writing expressions. Last—and, in this case, least—an animated Office Assistant attempts to anticipate users' questions about Access 97.

Microsoft Access 1.0 introduced a new approach to writing macros that automate repetitive database operations. Access 95's 40+ macro instructions were remarkably powerful; you could create quite sophisticated database applications by using only Access macros. Access 97 relegates macros to the "for backward compatibility only" category. Office 97 brings a common version 5.0 of 32-bit Visual Basic for Applications (VBA) to Access, Excel, Word, and even PowerPoint. Visual Basic 5.0 shares the same VBA engine with members of Office 97. VBA's syntax is easy to learn, yet it provides a vocabulary rich enough to satisfy veteran xBase and Paradox application developers. Making the transition from Access macros to VBA is important, because there's no guarantee that future versions of Access will continue to support macro programming.

Access 97 supports 32-bit Object Linking and Embedding (OLE) 2.1 as both a container (client) and as an ActiveX component (formerly OLE Automation server) application, giving you the benefits of in-place activation of objects, such as Excel 97 worksheets and Word 97 documents stored in Access databases. (Access 2.0 was an OLE 2.0 container application only.) Conversely, you can manipulate Access objects within an Excel 97, Word 97, Project 97, or 32-bit Visual Basic 4+ application. Access 97 also lets you manipulate ActiveX components created with Visual Basic 4+. LOBjects (Line of Business Objects) built with Visual Basic 4+ and shared with other VBA-enabled applications promise to make a major change in the methodology of creating enterprise-scale database applications.

Access 97 and Visual Basic 5.0 share the capability to take advantage of the new ActiveX controls (formerly OLE Controls) that Microsoft, third-party add-in software publishers, and you create. (The Control Creation Edition of Visual Basic 5.0 lets you design your own ActiveX controls that are compatible with Access 97.) ActiveX controls provide Access 97 with the extensibility that VBX custom controls brought to Visual Basic. Access 97 can accommodate almost every 32-bit OLE Control included with the Professional and Enterprise editions of Visual Basic 4.0. The new, lightweight ActiveX controls for Internet applications, many of which are available for downloading from http://www.microsoft.com, carry much less overhead. Other members of Office 97 also can take advantage of ActiveX controls in dialogs created with Microsoft's new Forms 2.0 technology.

Access is specifically designed for creating multiuser applications where database files are shared on networks, and Access incorporates a sophisticated security system to prevent unauthorized persons from viewing or modifying the databases you create. Access's security system is modeled on that of Microsoft SQL Server 4+. Access 2.0 simplified the labyrinthine security used by versions 1.x and made creating secure Access applications much easier. No substantial changes have been made to the Access security system in Access 97, but the User-Level Security Wizard introduced with Access 95 makes secure applications easier to implement.

Access has a unique database structure that can combine all related data tables and their indexes, forms, reports, macros, and VBA code within a single .mdb database file. It's now a generally accepted database design practice (GADBDP) to use separate .mdb files to contain data and application objects; your application .mdb links tables contained in the data .mdb. (The term link replaced attach beginning with Access 95.) Access 97 introduces a new file format, .mde, so that you can distribute Access applications without including your original VBA source code.

Access can import data from and export data to the more popular PC database and spreadsheet files, as well as text files. Access also can attach dBASE, FoxPro, and Paradox table files to databases and manipulate these files in their native formats. You also can use Access on workstations that act as clients of networked file and database servers in client/server database systems. Access, therefore, fulfills all the requirements of a professional relational database management system, as well as a front-end development tool for use with client/server databases. Microsoft has made several improvements to these features in Access 97. The most important new features of Access 97 are discussed in Chapter 1, "Access 97 for Access 95 and 2.0 Users: What's New."

Several chapters of this book are devoted to using Access 97 with other members of Office 97, such as Microsoft Excel 97 and Microsoft Word 97, plus Microsoft Graph 8.0 and the Paint applet supplied with Windows 95. Applets are small but useful applications supplied as components of major applications; Graph 8.0, for example, is an OLE 2.1 applet.

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