File Format fields order

[Grzegorz (Greg) Pasternak]

Doug;

You have made many valid points and I have seen and used it all.  Still, I prefer to stay away from MOFF's in any new library I design. 

On the other hand, I strongly agree on the "beer conversation" idea and hope that we can get together again in some forseable future.

Have a great day,

Greg


> On Sep 28, 2021, at 3:09 PM, Doug Easterbrook <doug at artsman.com> wrote:
> 
> hi Greg.
> 
> a word on MOFF’s….     which we use a lot .. but in this context.
> 
> MOFF’s
> 1) can can used for code completion when typing variable names
> 2) can go in query classes — as fake variables.
> 
> 
> we call them gVars for two reasons
> 1) they are global
> 2) they start with ‘g’ for easy identification.
> 
> for example, we might call one of the gIcon (character)
> 
> and in a query class that is used to fill a list based on a table…. we might see the following for a ‘customer’ list which is defined on this query
> 
> gIcon
> C_FIRST_NAME
> C_LAST_NAME
> etc
> 
> 
> so, when you do something like
> 
> do list.$definefromsqlClass(‘customerList’)
> do list.$getAllData.     (we have a function that does this)
> 
> 
> it makes sql that looks like
> 
> select gIcon,C_FIRST_NAME,C_LAST_NAME from customerfile where ….
> 
> 
> of course its going to fail because gIcon is not a field defined in a database.   and herein comes the cool trick that I’ve talked about at Euromnis
> 
> 
> Before we run the SQL, we have a function in the table class that is called. $getReplacementSelectNames
> 
> it might do this
> 
> Parameter  pSelectVars
> 
> calculate query as ‘   (select GetIconFunctionForCustomers(customerfile) as gIcons’
> calculare pSelectVars as replace(‘gIcons’,query,pSelectNames)
> 
> 
> the query now becomes
> 
> select (select GetIconFunctionForCustomers(customerfile) as gIcons,C_FIRST_NAME,C_LAST_NAME from customerfile where ….
> 
> 
> 
> 
> and that, because it executes on the server, is super fast.   We never play with lists as they are loading and do calculations on fields ….   never — it s too slow in omnis to unpack and pack a list for each line.
> 
> 
> 
> and the MOFF variable  gIcons is now in a list.
> 
> 
> it all works very neatly with omnis — since omnis things it is any other variable from the database.
> 
> 
> 
> and we stick style() icons into the gIcon to display icons at the left side of each row.
> 
> 
> 
> 
> 
> the concept..
> 1) declare global variables that are not part of the database
> 2) substitute functions, sub selects, or any valid sql for the variable to pull any data from anywhere
> 3) display it in a list.
> 4) reference it as list.gVariable
> 5) get code completion when referring to gVariable
> 6) have a definition for the variable so that when you look it up using f9 or hovering over the variable, it describes what its purpose is.
> 7) works when using foreground or background threads for sql — interchangeably.
> 
> 
> and there are more reasons we do it, but those are the basics.    it sure speeds up SQL… and it makes background loads work great.
> 
> 
> 
> but again, that is another beer conversation.  which I can’t wait to have again one day.
> 
> 
> 
> 
> Doug Easterbrook
> Arts Management Systems Ltd.
> mailto:doug at artsman.com
> http://www.artsman.com
> Phone (403) 650-1978
> 
>> On September 28, 2021, at 11:49 AM, Grzegorz (Greg) Pasternak <gpasternak at cogeco.ca> wrote:
>> 
>> 
>> 
>>> On Sep 28, 2021, at 12:42 PM, Das Goravani <goravanis at gmail.com> wrote:
>>> 
>>> 
>>>> 
>>>> Rudolf Bargholz
>> 
>>> It’s probably faster than repeat loop assigning values from Schema defined row to MOFF fields.. just assign row then load cols to fill the CRB
>>>> 
>> 
>> A comment about CRB, while it may be convenient to use at times I prefer to stay away from it, instead I prefer to work with vars of type row with relevant scope.  I dislike CRB because it is global and I never trust its state.  I prefer to avoid MOFF for the same reason.
>> 
>> Greg
>> 
>> 
>> 
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