The Workings of Workbooks

The core document of Excel is a workbook. Everything that you do in Excel takes place in a workbook.

Beginning with Excel 2007, workbook "files" are actually compressed folders. You may be familiar with compressed folders if you've ever opened a file with a .zip extension. Inside the compressed folders are a number of files that hold all the information about your workbook, including charts, macros, formatting, and the data in its cells.

An Excel workbook can hold any number of sheets (limited only by memory). The four types of sheets are

• Worksheets
• Chart sheets
• MS Excel 4.0 macro sheets (obsolete, but still supported)
• MS Excel 5.0 dialog sheets (obsolete, but still supported)

You can open or create as many workbooks as you want (each in its own window), but only one workbook is the active workbook at any given time. Similarly, only one sheet in a workbook is the active sheet. To activate a different sheet, click its corresponding tab at the bottom of the window, or press Ctrl+PgUp (for the previous sheet) or Ctrl+PgDn (for the next sheet). To change a sheet's name, double-click its Sheet tab and enter the new text for the name. Right-clicking a tab brings up a shortcut menu with some additional sheet-manipulation options.

You can also hide the window that contains a workbook by using the View --->Window --->Hide command. A hidden workbook window remains open but not visible. Use the View --->Window ---> Unhide command to make the window visible again. A single workbook can display in multiple windows (choose View --->Window---> New Window). Each window can display a different sheet or a different area of the same sheet.

Worksheets

The most common type of sheet is a worksheet-which you normally think of when you think of a spreadsheet. Every Excel 2007 worksheet has 16,384 columns and 1,048,576 rows. After years of requests from users, Microsoft finally increased the number of rows and columns in a worksheet.

How Big Is a Worksheet?

It's interesting to stop and think about the actual size of a worksheet. Do the arithmetic (16,384 × 1,048,576), and you'll see that a worksheet has 17,179,869,184 cells. Remember that this is in just one worksheet. A single workbook can hold more than one worksheet.

If you're using a 1024 × 768 video mode with the default row heights and column widths, you can see 15 columns and 25 rows (or 375 cells) at a time-which is about .000002 percent of the entire worksheet. In other words, more than 45 million screens of information reside within a single worksheet.

If you entered a single digit into each cell at the relatively rapid clip of one cell per second, it would take you over 500 years, nonstop, to fill up a worksheet. To print the results of your efforts would require more than 36 million sheets of paper-a stack about 12,000 feet high (that's ten Empire State Buildings stacked on top of each other).

Note  : Versions prior to Excel 2007 support only 256 columns and 65,536 rows. If you open such a file,  Excel 2007 enters compatibility mode to work with the smaller worksheet grid. In order to work with the larger grid, you must save the file in one of the Excel 2007 formats. Then close the workbook and reopen it.

Having access to more cells isn't the real value of using multiple worksheets in a workbook. Rather, multiple worksheets are valuable because they enable you to organize your work better. Back in the old days, when a spreadsheet file consisted of a single worksheet, developers wasted a lot of time trying to organize the worksheet to hold their information efficiently. Now, you can store information on any number of worksheets and still access it instantly.

You have complete control over the column widths and row heights, and you can even hide rows and columns (as well as entire worksheets). You can display the contents of a cell vertically (or at an angle) and even wrap around to occupy multiple lines.
Note :
By default, every new workbook starts out with three worksheets. You can easily add a new sheet when necessary, so you really don't need to start with three sheets. You may want to change this default to a single sheet. To change this option, use the Office --->Excel Options command, click the Popular tab, and change the setting for the option labeled Include This Many Sheets.

Chart Sheets

A chart sheet holds a single chart. Many users ignore chart sheets, preferring to use embedded charts, which are stored on the worksheet's drawing layer. Using chart sheets is optional, but they make it a bit easier to locate a particular chart, and they prove especially useful for presentations. I discuss embedded charts (or floating charts on a worksheet) later in this chapter.

Macro Sheets and Dialog Sheets

An Excel 4.0 macro sheet is a worksheet that has some different defaults. Its purpose is to hold XLM macros. XLM is the macro system used in Excel version 4.0 and previous versions. This macro system was replaced by VBA in Excel 5.0 and is not discussed in this book.

An Excel 5.0 dialog sheet is a drawing grid that can hold text and controls. In Excel 5.0 and Excel 95, they were used to make custom dialog boxes. UserForms were introduced in Excel 97 to replace these sheets.

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The Object Model Concept

If you've dealt with computers for any length of time, you've undoubtedly heard the term object-oriented programming. An object essentially represents a software element that a programmer can manipulate. When using Excel, you may find it useful to think in terms of objects, even if you have no intention of becoming a programmer. An object-oriented approach can often help you keep the various elements in perspective.

Excel objects include the following:

• Excel itself
• An Excel workbook
• A worksheet in a workbook
• A range in a worksheet
• A button on a worksheet
• A ListBox control on a UserForm (a custom dialog box)
• A chart sheet
• A chart on a chart sheet
• A chart series in a chart

Notice the existence of an object hierarchy: The Excel object contains workbook objects, which contain worksheet objects, which contain range objects. This hierarchy is called Excel's object model. Other Microsoft Office products have their own object model. The object model concept proves to be vitally important when developing VBA macros. Even if you don't create macros, you may find it helpful to think in terms of objects.

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The History of Excel

You probably weren't expecting a history lesson when you bought this book, but you may find this information interesting. At the very least, this section provides fodder for the next office trivia match.

Spreadsheets comprise a huge business, but most of us tend to take this software for granted. In the pre-spreadsheet days, people relied on clumsy mainframes or calculators and spent hours doing what now takes minutes.

It Started with VisiCalc

Dan Bricklin and Bob Frankston conjured up VisiCalc, the world's first electronic spread- sheet, back in the late 1970s when personal computers were unheard of in the office environment. They wrote VisiCalc for the Apple II computer, an interesting machine that seems like a toy by today's standards. VisiCalc caught on quickly, and many forward-looking companies purchased the Apple II for the sole purpose of developing their budgets with VisiCalc. Consequently, VisiCalc is often credited for much of Apple II's initial success.

Then Came Lotus

When the IBM PC arrived on the scene in 1982, thus legitimizing personal computers, VisiCorp wasted no time porting VisiCalc to this new hardware environment. Envious of VisiCalc's success, a small group of computer enthusiasts at a start-up company in Cambridge, Massachusetts, refined the spreadsheet concept. Headed by Mitch Kapor and Jonathon Sachs, the company designed a new product and launched the software industry's first full-fledged marketing blitz. Released in January 1983, Lotus Development Corporation's 1-2-3 proved an instant success. Despite its $495 price tag (yes, people really paid that much for a single program), it quickly outsold VisiCalc and rocketed to the top of the sales charts, where it remained for many years. Lotus 1-2-3 was, perhaps, the most popular application ever.

Microsoft Enters the Picture

Most people don't realize that Microsoft's experience with spreadsheets extends back to the early 1980s. In 1982, Microsoft released its first spreadsheet-MultiPlan. Designed for computers running the CP/M operating system, the product was subsequently ported to several other platforms, including Apple II, Apple III, XENIX, and MS-DOS. MultiPlan essentially ignored existing software user-interface standards. Difficult to learn and use, it never earned much of a following in the United States. Not surprisingly, Lotus 1-2-3 pretty much left MultiPlan in the dust.

Excel partly evolved from MultiPlan, first surfacing in 1985 on the Macintosh. Like all Mac applications, Excel was a graphics-based program (unlike the character-based MultiPlan). In November 1987, Microsoft released the first version of Excel for Windows (labeled Excel 2 to correspond with the Macintosh version). Excel didn't catch on right away, but as Windows gained popularity, so did Excel. Lotus eventually released a Windows version of 1-2-3, and Excel had additional competition from Quattro Pro-originally a DOS program developed by Borland International, then sold to Novell, and then sold again to Corel (its current owner).

Excel Versions

Excel 2007 is actually Excel 12 in disguise. You may think that this name represents the twelfth version of Excel. Think again. Microsoft may be a successful company, but its version-naming techniques can prove quite confusing. As you'll see, Excel 2007 actually represents the tenth Windows version of Excel. In the following sections, I briefly describe the major Windows versions of Excel.

EXCEL 2

The original version of Excel for Windows, Excel 2 first appeared in late 1987. It was labeled Version 2 to correspond to the Macintosh version (the original Excel). Because Windows wasn't in widespread use at the time, this version included a runtime version of Windows-a special version with just enough features to run Excel and nothing else. This version appears quite crude by today's standards

EXCEL 3

At the end of 1990, Microsoft released Excel 3 for Windows. This version offered a significant improvement in both appearance and features. It included toolbars, drawing capabilities, worksheet outlining, add-in support, 3-D charts, workgroup editing, and lots more.

EXCEL 4

Excel 4 hit the streets in the spring of 1992. This version made quite an impact on the marketplace as Windows increased in popularity. It boasted lots of new features and usability enhancements that made it easier for beginners to get up to speed quickly.

EXCEL 5

In early 1994, Excel 5 appeared on the scene. This version introduced tons of new features, including multisheet workbooks and the new Visual Basic for Applications (VBA) macro language. Like its predecessor, Excel 5 took top honors in just about every spreadsheet comparison published in the trade magazines.

EXCEL 95

Excel 95 (also known as Excel 7) shipped in the summer of 1995. On the surface, it resembled Excel 5 (this version included only a few major new features). However, Excel 95 proved to be significant because it presented the first version to use more advanced 32-bit code. Excel 95 and Excel 5 use the same file format.

EXCEL 97

Excel 97 (also known as Excel 8) probably offered the most significant upgrade ever. The toolbars and menus took on a great new look, online help moved a dramatic step forward, and the number of rows available in a worksheet quadrupled. And if you're a macro developer, you may have noticed that Excel's programming environment (VBA) moved up several notches on the scale. Excel 97 also introduced a new file format.

EXCEL 2000

Excel 2000 (also known as Excel 9) was released in June of 1999. Excel 2000 offered several minor enhancements, but the most significant advancement was the ability to use HTML as an alternative file format. Excel 2000 still supported the standard binary file format, of course, which is compatible with Excel 97.

EXCEL 2002

Excel 2002 (also known as Excel 10) was released in June of 2001 and is part of Microsoft Office XP. This version offered several new features, most of which are fairly minor and were designed to appeal to novice users. Perhaps the most significant new feature was the capability to save your work when Excel crashes and also recover corrupt workbook files that you may have abandoned long ago. Excel 2002 also added background formula error checking and a new formula-debugging tool.

EXCEL 2003

Excel 2003 (also known as Excel 11) was released in the fall of 2003. This version had very few new features. Perhaps the most significant new feature was the ability to import and export XML files and map the data to specific cells in a worksheet. It also introduced the concept of the List, a specially designated range of cells. Both of these features would prove to be precursors to future enhancements.

EXCEL 2007

Excel 2007 (also known as Excel 12) was released in early 2007. Its official name is Microsoft Office Excel 2007. This latest Excel release represents the most significant change since Excel 97, including a change to Excel's default file format. The new format is XML based although a binary format is still available. Another major change is the Ribbon, a new type of user interface that replaces the Excel menu and toolbar system. In addition to these two major changes, Microsoft has enhanced the List concept introduced in Excel 2003 (a List is now known as a Table), improved the look of charts, significantly increased the number of rows and columns, and added some new worksheet functions. For more, see the sidebar

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