A simple breakdown of the rather obscure XOR operator Help topic.
The Help topic for the XOr operator starts out rather obscurely by explaining that the operator is used to perform a logical exclusion on two expressions.
Then it goes from bad to worse:
“If one, and only one, of the expressions evaluates to True, result is True. However, if either expression is Null, result is also Null. When neither expression is Null, result is determined according to the following table:
|
If expression1 is |
And expression2 is |
Then result is |
|
True |
True |
False |
|
True |
False |
True |
|
False |
True |
True |
|
False |
False |
False |
The Xor operator performs as both a logical and bitwise operator. A bit-wise comparison of two expressions using exclusive-or logic to form the result, as shown in the following table:
|
If bit in expression1 is |
And bit in expression2 is |
Then result is |
|
0 |
0 |
0 |
|
0 |
1 |
1 |
|
1 |
0 |
1 |
|
1 |
1 |
0 |
”
The XOr operator, believe it or not, is actually a very simple concept, that can be explained to a four-year-old:
“You can have either a Twinkie or a Ho-Ho, but not both“
That’s it! The Help writers seem to have lost sight of their goal: to explain concepts so that average Access users can understand them, not to write abstruse commentaries more suited for a Ph.D. thesis or an advanced mathematical journal.
