In the Real WorldHeads-Down Data Entry

In the Real World Heads-Down Data Entry

This chapter's tables that list key combinations to expedite data entry make dull reading, at best. Special Edition Using Microsoft Office Access 2003 serves as both a tutorial and a reference, and references must be comprehensive. Detailed lists of Access 11 features and their functions, no matter how tedious the list or the features and functions, are unavoidable. There have been no significant changes to data entry key definitions since Access 2.0.

You probably won't appreciate the benefits of Access's data entry shortcut keys until you must type a large amount of table data in a Datasheet view. Clearly, it's preferable to import existing data, taking advantage of Access's flexible data import features described in Chapter 8. Almost everyone, however, faces the inevitable chore of typing table data, such as testing entries for a new database.

Comparing Heads-Down Keypunch Data Entry with Access's Datasheet View

In the days of supremacy of mainframe computers, most of which were less powerful than today's PCs, IBM 026 or 029 keypunch operators generated decks of 80-column punched cards from stacks of source documents. Keypunch operators often received piecework wages, based on the number of cards they produced; salaried operators usually had to fill a daily quota. The eyes of keypunch operators were focused eight hours per day on the top document of a stack, giving rise to the term "heads-down data entry."

Note

If you've never seen a punched card machine, there's a picture of an IBM 029 keypunch at http://info.ox.ac.uk/ctitext/history/keypnch.html. Ed Thelen, a computer historian, has posted a 34-page history of punched card computing at http://ed-thelen.org/comp-hist/CBC-Ch-04.pdf.

Datasheet view of a table or updatable query is the simplest and quickest means for heads-down addition of large numbers of records to tables. The need to scroll horizontally to expose more than the first few columns of a wide table, such as that for a customer name and address list, makes Datasheet entry a bit more cumbersome. If you're a good typist, using shortcut keys for column navigation quickly becomes second nature.

Datasheet view for adding related records was cumbersome in previous versions of Access, so most developers are accustomed to creating data entry form-subform pairs, described in Chapter 15, "Designing Custom Multitable Forms." Access 11, however, offers subdatasheets that let you add multiple related records almost as effortlessly as adding single records to base tables. The major shortcoming of subdatasheets is that expanding the subdatasheet requires a mouse click on the + symbol. Moving between heads-down keyboard data entry and mouse operations greatly reduces data-entry operator productivity.

Replacing the Punched Card Verifying Step

Verifying data to preserve domain integrity was a critical step in the keypunch process. The most common method of data verification, sometimes called validation, was retyping the original data to determine if the second typing pass matched the first. Clearly, this approach isn't practical in Datasheet view, although you could implement punched-card verification with a simple form and some VBA code to compare the two sets of entries.

Data verification and validation aren't synonymous. Verification attempts to eliminate typographic errors by duplication, whereas validation primarily tests data entry conformance to a fixed set of rules. The more clever you become in writing well-defined Access Validation Rules, the better the overall accuracy of the input data. Although form-level validation is more flexible, field- and table-level validation applies to data you enter with any form that's bound to the table. So, you avoid having to recreate validation operations in each of the multiple forms that permit table data entry. The most annoying thing about field- and table-level validation is having to repeatedly close Validation Text message boxes that describe data entry errors.

Where Not to Use Datasheet Entry

Datasheet entry works well for "punching" standard documents on a routine basis. Datasheet entry isn't suited to ad hoc situations, such as taking telephone orders or reservations, or other activities that involve lookup operations on related tables. The "In the Real World The Art of Form Design" section of Chapter 14, "Creating and Using Access Forms," describes some of the features of a typical Access data-entry form designed for heads-down telephone order taking. A single form with list and text boxes, and a subform that appears and disappears in concert with the current operating mode lets the operator quickly find an existing customer's record, list the customer's past and current orders, and add a new order with multiple line items. The form is designed expressly for keyboard-only operations to eliminate the transition to and from a mouse or trackball.