[AccessD] A2K Reference the dot column property in a query

Charlotte Foust cfoust at infostatsystems.com
Mon Oct 20 10:53:55 CDT 2003


But an optional argument can be any datatype, John.  Then instead of
IsMissing, you just check for the default value of the argument, an
empty string or a zero, etc.  

Charlotte Foust

-----Original Message-----
From: John Colby [mailto:jcolby at colbyconsulting.com] 
Sent: Monday, October 20, 2003 12:02 AM
To: Access Developers discussion and problem solving
Subject: RE: [AccessD] A2K Reference the dot column property in a query


I try and avoid variants as well.  Unfortunately IsMissing requires a
variant.  In this sort of application it appears to me that using a
variant is worthwhile to avoid the issue of "what is a valid 'not used'
value" and will that value be "not used" tomorrow.

John W. Colby
www.colbyconsulting.com

-----Original Message-----
From: accessd-bounces at databaseadvisors.com
[mailto:accessd-bounces at databaseadvisors.com]On Behalf Of Stuart Sanders
Sent: Monday, October 20, 2003 3:37 AM
To: 'Access Developers discussion and problem solving'
Subject: RE: [AccessD] A2K Reference the dot column property in a query


Yes ... You can't set variables declared as LONG/INTEGER/STRING etc as
null. Ie
  DIM lngi as LONG
  Lngi = NULL
This won't work ... It will generate an error.  You can only do that
with variants.  I usually try to avoid variants, so would use something
like
this:

STATIC FUNCTION StartDate(OPTIONAL dteStartDate as Date = 0) as Date
  Local dteStore as Date
  IF dteStartDate <> 0 Then
    dteStore = dteStartDate
  END IF
  StartDate = dteStore
End FUNCTION

Of course this assumes that 00:00:00 Jan 1 1890 (or whenever the start
value of the date variable is) is not going to be a valid input.

In some circumstances I add initialisation options.

Stuart

> -----Original Message-----
> From: accessd-bounces at databaseadvisors.com
> [mailto:accessd-bounces at databaseadvisors.com] On Behalf Of John Colby
> Sent: Monday, 20 October, 2003 3:16 PM
> To: Access Developers discussion and problem solving
> Subject: RE: [AccessD] A2K Reference the dot column property in a 
> query
>
>
> Arthur,
>
> The only way I was able to get this working was using an optional 
> VARIANT and checking IsMissing.  IsNull didn't work on a missing 
> integer.
>
> Static Function FltrSfrmClaimAssociatesCboContactSelFilter(Optional
> llngCTYID As Variant)
> Dim lngCTYID As Variant
>     If Not IsMissing(llngCTYID) Then
>         lngCTYID = llngCTYID
>     End If
>     FltrSfrmClaimAssociatesCboContactSelFilter = lngCTYID
> End Function
>
> It does work great though.  Set it up to be called in AfterUpdate of 
> the filter combo and used the function value in the dependent
> combo's query.
>
> John W. Colby
> www.colbyconsulting.com
>
> -----Original Message-----
> From: accessd-bounces at databaseadvisors.com
> [mailto:accessd-bounces at databaseadvisors.com]On Behalf Of Arthur 
> Fuller
> Sent: Saturday, September 06, 2003 2:49 PM
> To: Access Developers discussion and problem solving
> Subject: RE: [AccessD] A2K Reference the dot column property in a 
> query
>
>
> Thanks for the explication, Stuart!
>
> IMO the coolest thing about statics is that you can eliminate 
> references to forms. In the AfterUpdate event of some control, you 
> call the static function and pass the param. Anywhere else you need 
> it, call the func without a param. I don't like being tied to 
> particular forms being open. I
> want to be able to run a query etc. from the debug window
> anytime I want,
> and to set said static func from the debug window anytime I
> want. Statics
> give me this. That's why I love 'em.
>
> A.
>
> -----Original Message-----
> From: accessd-bounces at databaseadvisors.com
> [mailto:accessd-bounces at databaseadvisors.com]On Behalf Of Rocky Smolin

> - Beach Access Software
> Sent: Saturday, September 06, 2003 8:23 AM
> To: Access Developers discussion and problem solving
> Subject: Re: [AccessD] A2K Reference the dot column property
> in a query
>
>
> Oh.  That's very cool.
>
> Rocky
>
> ----- Original Message -----
> From: "Stuart McLachlan" <stuart at lexacorp.com.pg>
> To: "Access Developers discussion and problem solving" 
> <accessd at databaseadvisors.com>
> Sent: Friday, September 05, 2003 5:40 PM
> Subject: Re: [AccessD] A2K Reference the dot column property in a 
> query
>
>
> > On 5 Sep 2003 at 7:48, Rocky Smolin - Beach Access S wrote:
> >
> > > Must have missed that thread Arthur.  What are static functions?
> > >
> >
> >
> > Functions which retain the value of their variables between calls. 
> > Something like:
> >
> > STATIC FUNCTION StartDate(OPTIONAL dteStartDate as Date) as Date 
> > Local dteStore as Date IF NOT ISNULLl(dteStartDate) Then
> >      dteStore = dteStartDate
> > END IF
> > StartDate = dteStore
> > End FUNCTION
> >
> > Every time you call the function with a date parameter, it sets its 
> > value. Every time you call it without a parameter, it returns the 
> > last value set.
> >
> > You can now  you user select a start date on a "pick form"
> somewhere.
> > When they have picked it, set the value of  Startdate() with 
> > something like dteTemp = StartDate(txtStartDate)
> >
> > Now you can use "=StartDate()" in reports, queries, form filters etc

> > anywhere you like. It will return the selected value  until the user

> > goes back to the pick form and changes it.
> >
> >
> >
> > --
> > Lexacorp Ltd
> > http://www.lexacorp.com.pg
> > Information Technology Consultancy, Software
> Development,System Support.
> >
> >
> >
> > _______________________________________________
> > AccessD mailing list
> > AccessD at databaseadvisors.com 
> > http://databaseadvisors.com/mailman/listinfo/accessd
> > Website: http://www.databaseadvisors.com
> >
>
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