[AccessD] Change in the evaluation of IIF, or something else?

Andy Lacey andy at minstersystems.co.uk
Thu Feb 5 09:45:40 CST 2015


Yea, I kinda feared that. And yet here MS positively encourage what I've been
doing
 
" The default collection of a  Recordset  object is the  Fields  collection, and
the default property of a  Field
<https://msdn.microsoft.com/en-us/library/office/ff193203.aspx>  object is the
 Value <https://msdn.microsoft.com/en-us/library/office/ff195493.aspx>
 property. Use these defaults to simplify your code."
 
This is here, the description of the DAO recordset object. 
 
https://msdn.microsoft.com/en-us/library/office/ff197799(v=office.15).aspx
 
So I don't feel that big a numpty.
 
Andy
 
 
 
 

> On 05 February 2015 at 15:40 Jim Dettman <jimdettman at verizon.net> wrote:
>
>
> <<could crash in A2010 if the
> field is Null, when it wouldn't have in A97. >>
>
> Your going to bump into quite a bit of this.
>
> Starting with Access 2007, Microsoft tightened up on a lot of things in
> syntax checking and type conversions (thank VBA7). Just about every app
> needs a few tweaks as a result.
>
> Suffice to say you just can't get away with things you never really should
> have been able to in the first place<g>
>
> Jim.
>
> -----Original Message-----
> From: accessd-bounces at databaseadvisors.com
> [mailto:accessd-bounces at databaseadvisors.com] On Behalf Of Andy Lacey
> Sent: Thursday, February 05, 2015 09:56 AM
> To: Access Developers discussion and problem solving
> Subject: Re: [AccessD] Change in the evaluation of IIF, or something else?
>
> Hi Rocky
>
> Thanks. The problem though is not so much this line, which I can code around
> of
> course. I'm moving a ginormous db from A97 to A2010 and I've just discovered
> this difference between the way A97 handles this call (with tolerance and
> understanding) and the way A2010 does (with a dull thud). I have no idea how
> many similar instances like this there may be and no way of searching for
> them
> (see my last post). Any inbuilt function which I pass a field value (and
> there
> will be hundreds if not thousands of instances) could crash in A2010 if the
> field is Null, when it wouldn't have in A97.
>
> Cheers
>
> Andy
>
>
> > On 05 February 2015 at 14:46 Rocky Smolin <rockysmolin at bchacc.com> wrote:
> >
> >
> > Use Weekday(Nz(rst!fld))?
> >
> > R
> >
> >
> > -----Original Message-----
> > From: accessd-bounces at databaseadvisors.com
> > [mailto:accessd-bounces at databaseadvisors.com] On Behalf Of Andy Lacey
> > Sent: Thursday, February 05, 2015 4:13 AM
> > To: Access Developers discussion and problem solving
> > Subject: Re: [AccessD] Change in the evaluation of IIF, or something else?
> >
> > Well there's a thing.
> >
> > Weekday(Null) returns Null
> >
> > Weekday(var) where var is Null returns Null
> >
> > Weekday(rst!fld) where rst!fld is Null gives Invalid Use Of Null
> >
> > ????????
> >
> > Andy
> >
> >
> >
> >
> >
> > > On 05 February 2015 at 11:33 Gustav Brock <gustav at cactus.dk> wrote:
> > >
> > >
> > > Hi Andy
> > >
> > > How about:
> > >
> > > res = Weekday(var)
> > >
> > > or rather:
> > >
> > > res = Weekday(var, vbUseSystemDayOfWeek)
> > >
> > > Works in A2013.
> > >
> > > /gustav
> > >
> > > -----Oprindelig meddelelse-----
> > > Fra: accessd-bounces at databaseadvisors.com
> > > [mailto:accessd-bounces at databaseadvisors.com] På vegne af Andy Lacey
> > > Sendt: 5. februar 2015 12:08
> > > Til: Access Developers discussion and problem solving
> > > Emne: [AccessD] Change in the evaluation of IIF, or something else?
> > >
> > > Hi folks
> > >
> > > I'm moving an ancient and very big db from A97 to A2010. I've just
> > > been tripped up by a difference in behaviour when using IIF. Here's
> > > the line of
> > > code:
> > >
> > > res=IIF(IsNull(var),Null,Weekday(var))
> > >
> > > In A97 this works fine and gives me Null. However, in A2010 this is
> > > crashing with Invalid Use of Null. It must evaluate both true and
> > > false element(s) of the IIF regardless. (Queries do not appear to do
> this,
> > they work as before).
> > >
> > > Is this a general rule in A2010. Is there anything I can do to change
> > > this behaviour? I know I can code round it in a number of ways but
> > > finding all instances of this in a humungous db is a horrendous
> > > prospect. I'm praying for a magic answer.
> > >
> > > Hang on, read on.
> > >
> > > After a bit more digging I'm not sure now where this will and will not
> > arise.
> > > I just tried the following:
> > >
> > > res=iif(isnull(var),null,instr(var,"12345","1"))
> > >
> > > and, unlike the Weekday function, that crashes in A97 which blows out
> > > of the water the idea that the False part of the IIF function wasn't
> > > evaluated before.
> > > So now I'm not sure if there is a rule by which all functions abide.
> > >
> > > Confused.
> > >
> > > Oh and pleeease don't tell me that I shouldn't have coded like that in
> > > the first place. That wouldn't be helpful.
> > >
> > > Andy
> > >
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