Odd/Even Validation Rule between Two Fields

[BGlover]

Hi,
I am building a scoring system for an Archery Tournament and am trying to add some extra validation between two fields.
I want to check the contents of one field against another.
So if Field A has an even value, then Field B must also be even, and if Field A has an Odd value, Field B must be odd.
Would it also be possible to add an exception such that if Field B = 0 then the validation rule does not apply?
I am only a very occasional user of Access, and don't have a very good grasp of the code structure in it, but am prepared to try and learn.
Many Thanks and feel free to ask for more detail,
Ben

 

[John Big Booty]

Welcome to the forum.

You could have some code in the Before Update Event of Field B, along the line of;

[COLOR="DarkGreen"]'Check if Field B hold a Zero Value[/COLOR]
If Me.FieldB = 0 Then
     Exit Sub
End If

[COLOR="DarkGreen"]'Check if both fields are even[/COLOR]
If Int(Me.FieldA/2) - Me.FieldA/2 = 0 And Int(Me.FieldB/2) - Me.FieldB/2 = 0
     Exit Sub    [COLOR="DarkGreen"]'Both Fields Even[/COLOR]
Else
     MsgBox "Both Fields Must be Even, please check the value entered in Field B"
     Cancel = True
     Me.FieldB.SetFocus
     Exit Sub
End If

[COLOR="DarkGreen"]'Check if both fields are odd[/COLOR]
If Abs(Int(Me.FieldA/2) - Me.FieldA/2) = 0.5 And Abs(Int(Me.FieldB/2) - Me.FieldB/2 = 0.5)
     Exit Sub    [COLOR="DarkGreen"]'Both Fields Odd[/COLOR]
Else
     MsgBox "Both Fields Must be Odd, please check the value entered in Field B"
     Cancel = True
     Me.FieldB.SetFocus
     Exit Sub
End If

Warning: This is air code and may need some tweaking

 

[stopher]

Since x MOD 2= 0 for any even x we can do:

If Me.FieldB <> 0 Then
    If Me.FieldA Mod 2 <> Me.FieldB Mod 2 Then
        MsgBox "Fields must be either both even or both odd"
        'add some action here
    End If
End If

Chris

 

[John Big Booty]

Thanks stopher, much neater. I knew there'd be a more economic way to do that

 

[BGlover]

Thank You both of you, that has done the trick brilliantly, and taught me a little about the syntax used.
Ben G