Predicate change if attribute exists...?

[PencilEd]

I may have 2 resources with the following 'Dates'

1)
<Dates>
  <Date type='created' value='2008-03-05'>
  <Date type='modified' value='2009-01-10'>
</Dates>

2)
<Dates>
  <Date type='created' value='2008-02-12'>
</Dates>

I'm wanting to get a count of the records modified in a given year - of course... if no Date of type='modified' exists then the Date of type='created' should be counted.

So - the 2 records above would give 1 for 2008 (#2) and 1 for 2009 (#1, since it was last modified in 2009).

I'm using the following:

{count(collection($my_collection)/Dates/Date[@type = 'created']/@value[year-from-date(.) >= $year and year-from-date(.) < $year + 1])}

Is there a way to do something like [@type = {if exists(@type = 'modified') then 'modified' else 'created'}]?

[Adam Retter-3]

So you want created if modified does not exist? Well depending on the
structure of your data, there are a couple of options...

If your 'Dates' element always has just 'created' and/or 'modified'
dates in the order you describe, then you could use -

let $find-year := 1999 return

count(
   /Dates/Date[last()][year-from-date(@value) eq $find-year]
)


Otherwise, if you need to be more specific because your 'Dates'
element structure is more complex than you describe here (assuming
that modified always follows created)  -

let $find-year := 1999 return

count(
   /Dates/Date[@type =
('modified','created')][last()][year-from-date(@value) eq $find-year]
)


Cheers Adam.


2009/6/30 PencilEd <gstewart@...>:

>
> I may have 2 resources with the following 'Dates'
>
> 1)
> <Dates>
>  <Date type='created' value='2008-03-05'>
>  <Date type='modified' value='2009-01-10'>
> </Dates>
>
> 2)
> <Dates>
>  <Date type='created' value='2008-02-12'>
> </Dates>
>
> I'm wanting to get a count of the records modified in a given year - of
> course... if no Date of type='modified' exists then the Date of
> type='created' should be counted.
>
> So - the 2 records above would give 1 for 2008 (#2) and 1 for 2009 (#1,
> since it was last modified in 2009).
>
> I'm using the following:
>
> {count(collection($my_collection)/Dates/Date[@type =
> 'created']/@value[year-from-date(.) >= $year and year-from-date(.) < $year +
> 1])}
>
> Is there a way to do something like [@type = {if exists(@type = 'modified')
> then 'modified' else 'created'}]?
> --
> View this message in context: http://www.nabble.com/Predicate-change-if-attribute-exists...--tp24276541p24276541.html
> Sent from the exist-open mailing list archive at Nabble.com.
>
>
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--
Adam Retter

eXist Developer
{ United Kingdom }
adam@...
irc://irc.freenode.net/existdb

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