On 14/08/2012 10:34, Seref Arikan wrote:
> Greetings,
> According to adl 1.5 document on the openEHR web site (issued 25 Jan
> 2012), Section 5.3.6.3, the runtime paths for single valued attributes
> can omit node identifer.
> The example given in the document uses miles per hour and km per hour
> alternatives. The thing is, if the runtime path is what is going to be
> persisted (and I can't see any other practical cases), the persisted
> data will have no information to mark the semantics of the selection
> of an option among alternatives.
actually, this text is a bit misleading. If we have the archetype
ELEMENT[at0004] matches { -- speed limit
value matches {
QUANTITY[at0022] matches { -- miles per hour
magnitude matches {|0..55|}
property matches {"velocity"}
units matches {"mph"}
}
QUANTITY[at0023] matches { -- km per hour
magnitude matches {|0..100|}
property matches {"velocity"}
units matches {"km/h"}
}
}
}
then the data instance created from the at0022 form of the QUANTITY will
be (in dADL):
items = <
["1"] = < -- ELEMENT
archetype_node_id = <"at0004">
value = < -- QUANTITY
archetype_node_id = <"at0022">
magnitude = <25>
>
>
["2"] = <....>
etc
>
so the path items[at0004]/value[at0022] will choose the quantity,
although items[at0004]/value would do just as well. (Remember, the Xpath
equivalents are
items[@archetype_node_id='at0004']/value[@archetype_node_id='at0022']
etc - the [at0022] is just a shorthand selection predicate.)
The paths are not 'persisted' as such - just the data. The paths are
always derivates of the data.
>
> In case of a query such as get me all Xs where value is expressed as
> km per hour, the system can not know what which option was used: kmph
> or mph, because there is not node identifier.
in this case, use the path items[at0004]/value[at0022].
*
* - thomas
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