Test for Empty Portal

[evildan]

Is there a way to test for an empty portal before entering the portal?

Here's a sample of what I'm talking about.

[fmp-if: poral is empty]

show this number

[fmp-else]

[fmp-poral: MyPortal]

[fmp-field: MyPortal::name]

[/fmp-portal]

[/fmp-if]

Any ideas or code would be appreciated.

[The Bridge]

I try to get FileMaker to do as much of my processing for me instead of doing it through CDML.

Define a calculation field (unstored, number) in the database itself:

Is_Portal_Empty = not IsValid(Relationship_Name::Foreign_Key)

Where Relationship_Name is, obviously, the name of the relationship that the portal is based on, and Foreign_Key is the foreign key of the related DB. It doesn't necessarily have to be that field in particular, but it must be a field that will definitely have a value.

Then your CDML would be:

[FMP-If: Is_Portal_Empty.eq.1]

Show this number

[FMP-Else]

[FMP-Portal:Relationship_Name]

.

.

.

[/FMP-Portal]

[/FMP-If]

[Garry Claridge]

Another method is to test a field of the relationship to see if it is empty:

[FMP-If: myrel::afield .eq.]......

All the best.

Garry

[Keith M. Davie]

Garry, I thought we had just discussed checking a field to see if it is empty with evildan. You are providing "Another method is to test a field of the relationship to see if it is empty: [FMP-If: myrel::afield .eq.]."

That is essentially the same code which evildan had tried in his earlier thread and which did not work. As was discussed, a field, when using the comparators .eq. or .neq., must be compared with a literal (cdml reference). Lungfish offers such a comparison with a literal in his code. evildan said that what finally worked for him in the earlier problem was essentially "[FMP-If: myrel::afield .ncn. ""]"

When attempting to determine via a cdml if-conditional if a field is empty or not, one is well advised to use the comparators "contain" or "does not contain", or use a literal with .eq. or .neq..

As to the example presented by Lungfish he suggests,

"Define a calculation field (unstored, number) in the database itself:

Is_Portal_Empty = not IsValid(Relationship_Name::Foreign_Key) "

While this will work, one could also use the calculation (also unstored)

Is_Portal_Empty = case(IsEmpty(myrel::afield),0,1)

The literal "0" or "1" could then be used with the comparators .eq. or .neq.. The effect is the same as a boolean.

[The Bridge]

HI Keith,

In reply to:

---

As was discussed, a field, when using the comparators .eq. or .neq., must be compared with a literal (cdml reference).

---

Gosh, I hate to disagree with someone who otherwise validates my other suggestions, but I make extensive use of CDML comparisons without literals, e.g. [FMP-If: Fieldname.neq.], and they've never given me trouble. Usually I don't even include the official "Field:" in my FMP-If statement, unless it just ain't working. For one reason or another, Web Companion is a little flexible in the way it parses these tags.

Just a friendly FYI.

Lungfish (formerly The Bridge)

[Garry Claridge]

Keith,

I've used the comparison [FMP-If: field .eq.] a bit and it has always worked for me.

I did follow the discussion with Dan and I am still a little unsure why [FMP-If: field .neq.] did not work. Note that I do not like to use double negatives, hence have not used the logic this way.

Maybe worth some more testing! I will give it a go tomorrow.

All the best.

Garry

[Keith M. Davie]

Hey Lungfish and Garry, thanks for the input. I've never had it work without the literal.

I don't mind douible negatives if they work. Same with double positives (Yeah, right!).

[Garry Claridge]

I've been doing some experimenting (FMP5.5v2 OS X)

[FMP-If: field .eq.] and [FMP-If: field .neq.] work with standard fields.

They do not work with related fields!

'Get Smart' is about to start on TV so I will have to stop experimenting for the time being.

Catch you all later.

Garry

[The Bridge]

Aha! The old Gotta-Use-Literals-With-Portals Trick! Right, Chief?

Sorry, couldn't resist. Haven't seen Get Smart in ages.

[Garry Claridge]

OK, I'm much smarter now. I have a plan. (Missed it by thaat much!)

Create a calculated field which is simply one of the related fields. Place this field on your layout. Now test this field with:

[FMP-If: mycalcfield .eq.]No Portal Rows

[FMP-Else]

[FMP-Portal: myportal]

portal fields here

[/FMP-Portal]

[/FMP-If]

Hope this is of use.

Garry

[Jeff Spall]

Hi, I agree that the way to do this is in the database.

I use the 'empt portal' test for a news stories page, which shows a search return on records: 'latest news', 'more news', 'industry news', 'social news'. Each of these has a portal with the stories. If there are no stories in that section, it doesn't display the heading.

In the database, I have a calculation field 'counter' that counts the related records in the portal and I then do a find based on counter>0

like this:

"http://mydomain.com/FMPro?-db=news&-format=news.htm&-error=news.htm&-lay=layout1&-sortfield=appear_order&-sortorder=ascending&-op=gt&counter=0&-op=eq&appear=main_newspage&-find"

I kinda like to use calculations rather than 'IF"s because you can index them.

regards, Jeff

[Garry Claridge]

After having demonstrated the use of cdml for this, I must confess that I too use calculated 'flags' for checking the presence of rows in a portal.

Good to have a couple of ways to skin a cat

All the best.

Garry

[evildan]

I will try to use calculated fields to accomplish the portal test.

FYI, for anyone dealing with portals/CDML, In my tests, anything within the portal tags is just ignored if the portal is empty...

which is why the following code will not work all the time.

[fmp-portal: portal]

[fmp-if: portal::field .neq.] [fmp-field: portal::field2] [fmp-else] #2 [/fmp-if]

[/fmp-portal]

The test is only conducted if the portal contains a value. Seems silly that I didn't matter before the latest version update, and now it does, but hey, I'm not going to argue with the experts.

Secondly, but more importantly, I wanted to thank you all for your imput regarding this matter. I really do appreciate all of the help I get from this site. Honestly I would be lost without all of your insight.

[Keith M. Davie]

I think I've worked it out as well:

[fmp-if: keith::goes_to_sleep.eq.]

The issue will get resolved

[fmp-else]

Error. Error. Error.

[/fmp-if]