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Access 2002 Programming by Example
book

Access 2002 Programming by Example

by Bob Villareal
January 2002
Beginner content levelBeginner
576 pages
13h 23m
English
Que
Content preview from Access 2002 Programming by Example

Controlling Nulls

One of the common bugaboos that haunt novice Access programmers is working with null values. When a field or variable is Null, it signifies that it has no valid data. This is in contrast to zero-length, which means that the value contains a string that has a zero length, or Empty, which means that a variant variable has not been initialized (assigned a value for the first time). All three values are hard to distinguish because they all represent a non or blank value. To help you differentiate between the three, keep the following in mind:

  • Variant is the only data type that can hold the Empty, Null, and Nothing special values.

  • The Null, Empty, and zero-length values all have no character that outputs to either a screen or a printer. ...

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Publisher Resources

ISBN: 0789725940Purchase book