Masourmeh, There is no generics in XML Schema, hence you cannot define a single type for all intervals. The XSD does what compilers that support generics do and creates a real type for each type of T that is used with the generic type. It should also be noted that these IntervalOf* types are only used in XML Archetypes to make it easier to validate and use the resulting archetype document without an AM implementation. These IntervalOf* types are not used in openEHR RM data but instead uses the DV_INTERVAL type that allows any DV_ORDERED as the lower and upper without any insurance that they are of the same type and requires an RM implementation to enforce these RM assertions.
Heath From: [email protected] [mailto:openehr-technical-bounces at chime.ucl.ac.uk] On Behalf Of Masoumeh Seydi Sent: Monday, 21 December 2009 3:53 PM To: openehr-technical at openehr.org Subject: data types and structures questions Hi All, I've got some questions about data types and structures. I was wondering if someone could help me. 1. Why an item_single can,t be empty but other structures may be. I mean 'items" attribute's cardinality in item_single is 1..1 (and this is logical. coz' an item_single without element is meanless). But in other structures, the cardinality of "items" attribute is 0..1. What's the point of having an empty list or tree or table (without ant item in it)? 2. What's the difference between CLUSTER and ITEM_TREE? Both can have CLUSTERs and ELEMENTs. And why in all structures in CKM, there is a Data branch shown in archetype mindmap but in cluster archetypes, there is a Items branch? 3. There is an Interval intrface containing lower and upper attributes. Other intervals like IntervalOfReal, IntervalofDate, IntervalofDateTime, IntervalofTime and IntervalofDuration with lower and upper attributes in xsd file in the site. My question is, why there is not an Interval class that contains an attribute for declaring the type of interval and so get rid of other interval classes for every type? Thanks in advance Masoumeh -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.openehr.org/mailman/private/openehr-technical_lists.openehr.org/attachments/20091222/de20a131/attachment.html>
