= Metadata Record Sibling Relationships =

|| '''Date''' || 2012/09/20 ||
|| '''Contact(s)''' || Simon Pigot ||
|| '''Last edited''' || 2012-09-20 ||
|| '''Status''' || complete, being discussed ||
|| '''Assigned to release''' || 2.9.0 ||
|| '''Resources''' || Available ||
|| '''Ticket #''' || #XYZ ||

== Overview ==

ISO Metadata records can be related to one another in different ways. The mechanisms for handling these relationships are most often part of the standard in the form of specific elements eg. parent-child relationships are handled through the parentIdentifier element and the datasets that a service delivers are handled through the operatesOn element. !GeoNetwork:
 * can index these relationships to support search
 * has services for retrieving a specific set of related records or the entire collection of related records
This proposal adds sibling relationships between metadata records to !GeoNetwork. The elements in the ISO standard that support sibling relationships are the aggregatedInformation element. Sibling relationships types can be specified using an extendible codelist. Sibling records would be displayed under the relationship type. An example of how sibling relations are displayed in the classic interface and the new ExtJS interface is shown below.

[[Image(ClassicSiblingRelationships.png)]]
[[Image(NewSiblingRelationships.png)]]

=== Proposal Type ===
 * '''Type''': GUI Change, Core Change
 * '''App''': !GeoNetwork
 * '''Module''': Lucene Index, ExtJS Experimental Interface, Classic Interface, Services for metadata record relations

=== Links ===
 * '''Documents''': 
 * '''Email discussions''':
 * '''Other wiki discussions''':

=== Voting History ===
 * Vote to be proposed by Simon Pigot, result was +/-n (m non-voting members).

----

== Proposal == 

Aggregate Information in an ISO record that has a related sibling record uses the aggregateInformation elements. This looks something like the following:

{{{
    <gmd:aggregateInformation>
        <gmd:MD_AggregateInformation>
            <gmd:aggregateDataSetIdentifier>
                <gmd:MD_Identifier>
                    <!-- optional gmd:authority here: could have details of a register describing the some details of the sibling record -->
                    <!-- code is UUID/urn of the sibling record, could be a gmx:Anchor -->
                    <gmd:code>
                        <gco:CharacterString>urn:marine.csiro.au:project:1532</gco:CharacterString>
                    </gmd:code>
                </gmd:MD_Identifier>
            </gmd:aggregateDataSetIdentifier>
            <gmd:associationType>
                <gmd:DS_AssociationTypeCode codeList="http://...#DS_AssociationTypeCode" 
                                            codeListValue="crossReference">crossReference</gmd:DS_AssociationTypeCode>
            </gmd:associationType>
            <!-- initiative type describes the type of sibling relationship - in this case the code is a project 
                 related to the record that contains this aggregateInformation -->
            <gmd:initiativeType>
                <gmd:DS_InitiativeTypeCode codeList="http://...#DS_InitiativeTypeCode" 
                                           codeListValue="project">project</gmd:DS_InitiativeTypeCode>
            </gmd:initiativeType>
        </gmd:MD_AggregateInformation>
    </gmd:aggregateInformation>
}}}


=== Backwards Compatibility Issues ===
None known.

=== New libraries added ===
None required.

== Risks ==
As is the case with many features of the ISO standard, best practice for the use of the aggregateInformation element is not defined. There is a risk that they way in which we are using this element will not suit all users. However one way of developing best practice is to attempt to use the element in different ways and accumulate experience which we hope will not be too bitter :-)

 
== Participants ==
 * Simon Pigot