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How to test a iw_sql_query result before iterating over it?

OctavianMH

Greetings,

Thanks in advance for any help! Basically, what I have here is a template that queries over a result set, formatting results.. but at certain times of the year (summer) there ARE NO results...and I need to output something special during those times. So.. what I need to do is run the query, and then test whether there's any output, so i can display my "come back later" message. I assume I can easily write an 'expr' that will reference the iw_sql_query i just made, but have no idea how to refer to the values in the query outside of an iterate tag.

I hope that made sense.. how would I make this happen?

Matt

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Comments

Adam Stoller

It might be easier to help you if you posted the code you are using and highlight the place where you believe the problem exists.

Also - please indicate the version(s) of the product(s) being used as well as the platform(s)/OS(s).

Sailesh

Not sure what you mean by "how to refer to the values in the query outside of an iterate tag."

But if you just want to check if your resultset is empty and based on which you want to display a special message; you can just simply check if resultset is null or empty before running the iterate, only if there are values run iterate.

OctavianMH

Here's the code:


{iw_sql_open  data_source = "dbiDBC:teamsite"
        user_name   = "*"
        password    = "*"
        connection  = "*"}
        {iw_sql_query connection='teamsite' result_set="eventList">
            {iw_value name='$sql'/}
        {/iw_sql_query}
                    {iw_if expr='! defined $eventList'}
                   {iw_then}
                             Exceptional Content Here
                   {/iw_then}
                    {/iw_if}
                    {iw_else}
                        {iw_sql_iterate var='events' result_set='eventList'}
                              Normal Flow Here
                        {/iw_sql_iterate}
                    {/iw_else}
{/iw_sql_open}

Sorry for the brackets, it wasn't rendering without them.

Indeed, I just want to test if eventList is undef..is the above correct?

Running TS 6.5.0 SP 1 on Unix

THANKS in advance!

matt

Adam Stoller

Here's the code:
[...]
Sorry for the brackets, it wasn't rendering without them.

Indeed, I just want to test if eventList is undef..is the above correct?

Running TS 6.5.0 SP 1 on Unix

THANKS in advance!

matt

I'm not sure of the exact syntax (if it were perl it would be trivial) and have no way of testing it right now - but I think !defined() is probably incorrect. The result_set is defined, it just may be empty - so you want to somehow test the size - or number of elements contained within - the result_set.

As a rough guess - it might be something like:

...
                    <iw_if expr='scalar(@{$eventList} == 0)'>
...

hopefully that's close enough (if not the actual right way) for you to play with it and get it working....

OctavianMH

Greetings,

I've finally returned to this project and want to put it to bed!!

unfortunately:

@{iw_if expr='scalar(@{$eventList} == 0)'}

doesn't complile.

nor does:

Sorry to be so perl clueless, but any hint as to what's going on here would be appreciated. I know what the code is attempting to do.. but can't quite figure out a fix.

Adam Stoller

Greetings,

I've finally returned to this project and want to put it to bed!!

unfortunately:

@{iw_if expr='scalar(@{$eventList} == 0)'}

doesn't complile.

nor does:
<iw_if expr='scalar(@{$eventList}) == 0'>

Sorry to be so perl clueless, but any hint as to what's going on here would be appreciated. I know what the code is attempting to do.. but can't quite figure out a fix.

Whoops - yeah - the second one is syntactically correct - my goof in the previous post - the only change I can think of is that perhaps you need to use double-quotes for surrounding the attribute value rather than single-quotes.

If that still doesn't work - I suggest compiling it with iwpt_compile.ipl using the -ocode flag and see if you can debug it further that way.

Sorry.

OctavianMH

After running the tpl with -ocode, I get the following error attached to the code we're working with above:



        if (1) {    # bare "{"  messes up iw_next !
            my $iw_if =  (scalar(@{$eventList}) == 0) ? 1 : 0;

Any suggestions?

ISCBorisB

After running the tpl with -ocode, I get the following error attached to the code we're working with above:

if (1) { # bare "{" messes up iw_next ! my $iw_if = (scalar(@{$eventList}) == 0) ? 1 : 0;

Any suggestions?

[html]

something

something else

something

something else

[/html]

OctavianMH

Heh.. that part had been fixed..

And how do you guys get lessthan greaterthan signs to show? When I put them inside of code tags, they don't show up... Smiley Sad

Here's the offending block again:



            {iw_if expr='scalar(@{$eventList}) == 0'}
             {iw_then}
                       content follows, like the below:
             {item}
              {title}There are no events this week{/title}
             {item}
             {/iw_then}
            {/iw_if}

ISCBorisB

Heh.. that part had been fixed..

And how do you guys get lessthan greaterthan signs to show? When I put them inside of code tags, they don't show up...

Here's the offending block again:

{iw_if expr='scalar(@{$eventList}) == 0'} {iw_then} content follows, like the below: {item} {title}There are no events this week{/title} {item} {/iw_then} {/iw_if}

Heh... Rudimentary Fragment above is malformed. Your problem is somewhere outside of
<iw_if expr='scalar(@{$eventList}) == 0'> This piece is correct. Attach your complete TPL

OctavianMH

I've attached the offending tpl. Not sure what's malformed re: the above, no need to laugh at me though. Smiley Happy

Some segments have been deleted to protect the innocent. This TPL compiles correctly without the offending segment. Again, the goal of all this is to cover an exception period of time where my sql query returns no results (no concerts in the upcoming 7 days, specifically).

Thanks in advance!

ISCBorisB

I've attached the offending tpl. Not sure what's malformed re: the above, no need to laugh at me though. Some segments have been deleted to protect the innocent. This TPL compiles correctly without the offending segment. Again, the goal of all this is to cover an exception period of time where my sql query returns no results (no concerts in the upcoming 7 days, specifically).

Thanks in advance!

I did not laugh, you started your reply with "Heh..." and I just followed suit :-D

Again, your issue has nothing to do with iw_if syntax, something like the following compiles and executes perfectly well[html]

<br> my $eventList = ();<br>

There are no events this week
http://www..org/
http://www..org/
Please visit .org for more information.

[/html]If I were you. I would start by making baby steps: Set PT skeleton, run, elaborate on single piece and run again, etc
In my own place I would write it all as Perl code in the single iw_perl tag and let masohists sort out IW PT Tags peculiarities

OctavianMH

Heh.. thing is, the tpl compiles and executes perfectly WITHOUT the offending iw_if block also. I added the offending block AFTER this tpl had been running great for months without problems.

THIS line is the problem, I promise:
iw_if expr='scalar(@{$eventList}) == 0'

Referring to your post above, are you sure:

my $eventList = ();

is equivalent to:

{iw_sql_query connection='teamsite' result_set="eventList"}
{iw_value name='$sql'/}
{/iw_sql_query\}

?

I think the issue lies in the comparison, perhaps we're confusing datatypes?

ISCBorisB

Referring to your post above, are you sure: my $eventList = (); is equivalent to...

No, I'm not sure about that. I used it as a shortcut to run it on my TS. Please note however that I repeated time and again that your issue is not offending line syntax.
So far you listed only one error manifestation:

After running the tpl with -ocode, I get the following error attached to the code we're working with above:
if (1) { # bare "{" messes up iw_next !
my $iw_if = (scalar(@{$eventList}) == 0) ? 1 : 0;

That's syntax problem. Any "datatype confusion" will manifest an error Run-Time, not during compilation.

preview.pdf

OctavianMH

Done.

The below functions perfectly:


{iw_perl}
     my $size = scalar(@eventList);
{/iw_perl}

{iw_if expr='$size == 0'}
     blahblah
{/iw_if}

Thanks for all your help guys, it definitely led me in the right direction.