[AccessD] Class costs & benefits

William Hindman wdhindman at dejpolsystems.com
Wed Feb 25 17:17:21 CST 2009


...yes and no ...multiple inheritance ala c++ is not possible but dotnet 
does support multiple interface inheritance which gets you a good long way 
down the road :)
...btw, I'm a flounderer and quite accepting of it ...I just keep on keeping 
on :)

William

--------------------------------------------------
From: "jwcolby" <jwcolby at colbyconsulting.com>
Sent: Wednesday, February 25, 2009 5:57 PM
To: "Access Developers discussion and problem solving" 
<accessd at databaseadvisors.com>
Subject: Re: [AccessD] Class costs & benefits

> William,
>
> AFAIK multiple inheritance is not possible in .Net either right?
>
> So yes, inheritance is a really cool feature, and it does not exist in 
> Access.
>
> OTOH, even in .Net there are things that you want to program that don't 
> inherit from anything.
> Business class objects come to mind.
>
> I'll tell you a little story.
>
> When I was in Mexico I was worked on a vending machine project, broken 
> into three parts.  There was
> a database in a handheld computer, written in Foxpro for DOS (no 
> inheritance).  There was a database
> on the desktop written in FoxPro for Windows which had inheritance, and 
> there was the vending
> machine itself (my part) written in C running on a ZWorld z80 based uC. 
> The HH code was written and
> debugged.  The vending machine code was written and debugged.  The desktop 
> db was hopelessly bogged
> down in discussions on what should be inheriting what base stuff, what 
> should be inheriting from the
> stuff that they managed to write etc.  It was fascinating to sit at the 
> edges of and watch.
>
> Now... this was mid 90s and I guess that the inheritance thing was new to 
> these guys but the point
> remains that inheritance is a double edged sword.  Once you understand and 
> can correctly and quickly
> make such choices, it can be very powerful.  Until that point you can 
> flounder around a lot...
>
> I do agree that the .Net framework is one of the most powerful frameworks 
> I have ever seen.  Nothing
> short of awesome IMHO.
>
> John W. Colby
> www.ColbyConsulting.com
>
>
> William Hindman wrote:
>> ...ok ...a basic view ...the real value comes when you can inherit from 
>> more
>> than one object and you can pick and choose what you inherit ...within
>> reason, you can build practically anything without having to start from
>> scratch ...VS gives you some basic tools, a grid for instance ...and you 
>> can
>> go a long time before it dawns on you that you don't have to accept that
>> basic grid ...you can reach back in the object hierarchy and build a grid
>> that does what YOU need ...a treeview with a grid node for instance 
>> ...all
>> without having to lay out bucks for third party tools that only do half 
>> of
>> what you wanted.
>>
>> ...to me, that's the real value of working with dot net ...there is 
>> sooooo
>> much built in high level stuff that lets you easily build low level 
>> custom
>> objects for your apps ...and sooooooo many blogs out there with guys 
>> doing
>> highly creative things that its nigh impossible to keep up.
>>
>> William
>>
>> --------------------------------------------------
>> From: "jwcolby" <jwcolby at colbyconsulting.com>
>> Sent: Wednesday, February 25, 2009 4:14 PM
>> To: "Access Developers discussion and problem solving"
>> <accessd at databaseadvisors.com>
>> Subject: Re: [AccessD] Class costs & benefits
>>
>>> The simplest illustration is to say that inheritance is the ability to
>>> define your own object as
>>> starting from something already in existence.
>>>
>>> Inheritance in the programming world mimics inheritance in the genetic
>>> world except that in most
>>> languages you are only allowed to inherit properties from a single 
>>> parent.
>>>
>>> So.  I am my dad.  I get everything my dad has, his eyes, his height, 
>>> his
>>> race, his ...
>>>
>>> I add to what I inherited.
>>>
>>> I add a bunch of extra pounds.  I add the experience of living in Mexico
>>> for five years.  I add the
>>> knowledge of building computers.
>>>
>>> In programming.  I inherit a text control.  I add code to check my 
>>> control
>>> source to see what data
>>> type it is.  I then add new method to make my display format depend on 
>>> the
>>> data type I am bound to.
>>>
>>> I have all of the normal properties of a text box.  I can generate all 
>>> of
>>> the events that the text
>>> box generated.  But I have additional code to check my data type and
>>> format myself differently
>>> depending on the data type.  And other useful things.
>>>
>>> That in a nutshell is inheritance.
>>>
>>> Access does not have inheritance.  That doesn't Accesses classes useless
>>> however.  A class is far
>>> more than the ability to inherit another object, even in languages where
>>> inheritance is possible.
>>>
>>> John W. Colby
>>> www.ColbyConsulting.com
>>>
>>>
>>> Rocky Smolin at Beach Access Software wrote:
>>>> "I will promise to treat every opinion as valid and not go into rant
>>>> mode.
>>>> ;)" Gonna be a pretty dull thread.
>>>>
>>>> For those of who don't know, can you define inheritance?
>>>>
>>>>
>>>> Rocky Smolin
>>>> Beach Access Software
>>>> 858-259-4334
>>>> www.e-z-mrp.com
>>>> www.bchacc.com
>>>>
>>>>
>>>>
>>>> -----Original Message-----
>>>> From: accessd-bounces at databaseadvisors.com
>>>> [mailto:accessd-bounces at databaseadvisors.com] On Behalf Of jwcolby
>>>> Sent: Wednesday, February 25, 2009 7:48 AM
>>>> To: Access Developers discussion and problem solving
>>>> Subject: [AccessD] Class costs & benefits
>>>>
>>>>  From Rocky's email I thought that perhaps a thread on what the costs 
>>>> and
>>>> benefits are for classes.
>>>>
>>>> Jim made a statement that he felt that "Access has no implementation
>>>> inheritance and since inheritance really is the whole point of using
>>>> classes, I think they are more or less a waste in Access".
>>>>
>>>> So what are your feelings and opinions about classes?
>>>>
>>>> I will promise to treat every opinion as valid and not go into rant 
>>>> mode.
>>>> ;)
>>>>
>>>> In fact I will promise to not respond to any message unless the author
>>>> specifically asks me to for some reason.
>>>>
>>>> --
>>>> John W. Colby
>>>> www.ColbyConsulting.com
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>>>> Website: http://www.databaseadvisors.com
>>>>
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>>
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