Calculated Value Wows..

[preston2]

Re: Calculated Value Wows..

While I am sure everyone here knows this;

A Calculated Field is a calculation done on a field at the table level.
A Calculated Value is a calculation done on a form and even though the A5 developer calls it a Calculated Field, it is not.


This is the first time I have tried using calculated values on a form. Most of the time I use vars or table fields and do the calculations in scripts and some in-table calculated fields.

Scripts have to be triggered to run and calculate, calculated fields need something in the table to change in order for a calculated field to recalculate. Calculated Values on a form will recalculate anytime the record is committed.

So each method needs something to happen before the calculations will recalculate. I have no issue with this.

While I could just take the code from a calculated value and place it in a script it would not be the best thing to do. Using it in a script I can streamline the logic to make the code execute faster based on current logic.

I just tried the Calculated Values to see what would happen and if there was any benefit to using them and I do not see any.

What prompted this thread was not whether to use Calculated values or not but to discus the strange problem I was having getting a Calculate Value to be written to a table field. The strange thing of it working for a while using one line of code and then quit working and having to use another few lines of code. And every time it would quit working all it would take is to swap back to the line of code that quit working before. So just switching two sets of code back and forth every time it would quit working.

As for "Why 100 lines of code", well I was being conservative. My apps are not the common run of the mill product sales and invoicing type systems where you have products you pick and they have a price assigned to them. In the industry my apps are designed for each product can have literally thousands of different price possibilities.

I am with Dave on this so I will be changing everything back over to scripts and functions. I was just trying to see what the deal was with Calculated Values. I see them as a possibility if you only need that calculation done on a single form and not using the results anywhere else. Other than that I can see no use for them.

Now all that said, FlieMaker handles them very well as Calculated Value on a form is in reality still directly tied to the calculation being done at the table field level. In other words a Calculated Field. There is no difference between the two in FileMaker. But I do not really like FileMaker.

[G Gabriel]

Re: Calculated Value Wows..

You hit the nail on the head by stating the obvious that a calc "field" on a form is a value not a field.
People use these interchangeably for convenience.
The calc "field" is nothing but a control displaying the output of the calculation.
The Supreme Court once declared that a corporation is an individual. I am pretty sure the Supreme court will unanimously declare that a calc "field" is not an individual and that explains the "strange" behavior you are referring to.
A field is an individual. It has eyes, ears, arms, legs..i.e: text, size, width, height, value..etc. So, if you want alpha to assign one of these attributes to another field, it can, because it's there.
But a calc "field" is not an individual. It has only the displaying attributes, but no value.
The value only happens when the calculation is invoked.
So, when you tell alpha to go get that "field"'s value, it throws the error that this handle does not exist.
Then you ask: How come it worked in some occasions but not others?
I am assuming is because somehow those lines of code invoked the calculation while the others didn't and hence my suggestion to force alpha to recalculate this none-individual and give it a value.

[preston2]

Re: Calculated Value Wows..

You hit the nail on the head by stating the obvious that a calc "field" on a form is a value not a field.
Then you ask: How come it worked in some occasions but not others?
I am assuming is because somehow those lines of code invoked the calculation while the others didn't and hence my suggestion to force alpha to recalculate this none-individual and give it a value.

No, the lines of code are in a script that gets run every time a button is pushed which is what makes the "work with this code for a while and then stop working" even more perplexing. I can see it either not working or not but to work for awhile, then stop, then when the next variation of code quits, go back to the first. The only thing I can think of is Alpha is using a undefined pointer and not clearing it so after so many times it say "I do not know what the heck you are talking about, there is no Calc->Price_subtot"


Who knows..

[MoGrace]

Re: Calculated Value Wows..

Then it must be a timing issue or some bypassed code in the script for the calc to get updated sometimes and get lost other times. If you have any conditions in the script, then you might be bypassing an assignment that causes the script to lose this calc.

I am fond of writing everything to the trace window while I am testing ;). And identifying each section with labels.

Debuggerimpaired...

[preston2]

Re: Calculated Value Wows..

Then it must be a timing issue or some bypassed code in the script for the calc to get updated sometimes and get lost other times. If you have any conditions in the script, then you might be bypassing an assignment that causes the script to lose this calc.

I am fond of writing everything to the trace window while I am testing ;). And identifying each section with labels.

Debuggerimpaired...

I would think so as well but when it is only the one line of code in the script.. timing issue against what?

[G Gabriel]

Re: Calculated Value Wows..

Try this at the start of your script:
tbl=table.open(".......your table......")
tbl.query_detach_all()
tbl.close()

[MoGrace]

Re: Calculated Value Wows..

Hi Preston,
Not having seen the script leaves us with only guesses.

[preston2]

Re: Calculated Value Wows..

Hi Preston,
Not having seen the script leaves us with only guesses.

The script was in the first post.