Microsoft Access Database Programmer Charleston West VA

Microsoft Access Programmer Information

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The following material is shared here to indicate our commitment to professional Microsoft Access programmer services in the Charleston West VA area. Access programming for business is highly complex and requires dedication and skill to create a high quality database application. We wrote the book on Microsoft Access prgramming, so you know you will get the best possible Access database solution for your business.

Working with Constants

A constant is a meaningful name given to a meaningless number or string. Constants can be used only for values that don't change at runtime. A tax rate or commission rate, for example, might be constant throughout your application. There are three types of constants in Access:

1. Symbolic

2. Intrinsic

3. System defined

Symbolic constants, created by using the Const keyword, are used to improve the readability of your code and make code maintenance easier. Instead of referring to the number .0875 every time you want to refer to the tax rate, you can refer to the constant mccurTaxRate. If the tax rate changes, and you need to modify the value in your code, you'll make the change in only one place. Furthermore, unlike the number .0875, the name mccurTaxRate is self-documenting.

Intrinsic constants are built into Microsoft Access; they are part of the language itself. As an Access programmer, you can use constants supplied by Microsoft Access, Visual Basic, Data Access Objects (DAO), and ADO. You can also use constants provided by any object libraries you're using in your application.

There are only three system-defined constants—True, False, and Null—and they are available to all applications on your computer.

Working with Symbolic Constants

As mentioned, you declare a symbolic constant by using the Const keyword. You can declare a constant in a subroutine or function, or in the General section of a Form or Report module. You can strong-type constants in Access 2000 and later. The declaration and use of a private constant looks like this:

Private Const TAXRATE As Currency = .0875

This code, when placed in a module's Declarations section, creates a private constant called TAXRATE and sets it equal to .0875. Here's how you use the constant in code:

Function TotalAmount(curSaleAmount As Currency)

TotalAmount = curSaleAmount * TAXRATE

End Function

This routine multiplies the curSaleAmount, received as a parameter, by the constant TAXRATE. It returns the result of the calculation by setting the function name equal to the product of the two values. The advantage of the constant in this example is that the code is more readable than TotalAmount = curSaleAmount * .0875 would be.

Access Programmer for Charleston West VA Attribution

This material originally appeared in Alison Balter's book Mastering Microsoft Office Access 2007 Development. Reprinted here by author's permission.

When you need a Microsoft Access programmer for your Charleston West VA business, call MS Access Solutions at (323) 285-0939. We have over 25 years experience in Microsoft Access programmer solutions. We create Access database applications for all sectors, consisting of hospitals, government agencies, the U.S. military, universities, agriculture, workers services, and insurance provider. We can take care of the most advanced as well as complicated Access and SQL Server database programming for your business as well as smaller projects, like fixing damaged Access database forms, MS Access reports, Access macros, and VBA code.

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