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Monday, October 03, 2005

Understanding And Using Bitfields
By Joey Davis @ 8:37 PM :: 1315 Views :: 0 Comments ::

Overview And Purpose Of This Article
The purpose of this article is to help you understand what a bitfield is, why you would care to use them and how they work. That is, how they work in Access and VBA. I’m not going to get down to ones and zeros because VBA masks that level of detail and you don’t need it to use this technique effectively. KEY CONCEPT : as mentioned above, a bitfield is a single value (in VBA, typically LONG INTEGER) that can represent zero or more options. Here is an example: Your client has you working on a database that tracks the shipping schedule to customers. Your client ships 7 days a week, so you might be tempted to add 7 Yes/No fields to the customer table (one for each day of the week). While using 7 different fields will work, I believe that it is a better design to use one single field - a bitfield.

Article Topics

This article will highlight some key querying tips for Microsoft Access. You'll find the tips covering from Beginning to Advanced topics. Enjoy.

How to best use the concation operators with Nulls in a query.
Include a date range in a report.
Use wildcards in parameter queries.
Using IN SELECT in your criteria for a field.

Seth

PS. Text in RED is something you type. Text in BLUE is something the computer displays.