[DDI-SRG] Discussion on BUG 114

[Wendy Thomas]

To make this functional DataItem should be nested in NCubeInstance. With 
these two items as siblings, the advantage of a DefaultNCubeReference and 
DefaultMeasure is limited. While helpful for files containing single 
NCubes a large number of very large files contain multiple NCubes with 
their contents strung out in a single record. The need as expressed above 
is accurate, but the solution is only half-way there.

Alternate suggestion is to

RecordLayoutType
    PhysicalRecordSegmentReference 1..1
    NCubeInstance 1..n
       ADD DefaultMeasureValue 1..n
       DataItem 1..n
         REMOVE NCubeInstanceReference  [*** see note below]
         CHANGE MeasureValue to AlternateMeasureValue 0..n



This means that a RecordLayout for NCubes would contain a reference to its 
PhysicalRecordSegment which provides the link back to the LogicalRecord 
description.

Each NCube in the PhysicalRecordSegment is described as a unit, 
NCubeInstance.
EAch NCube Instance would provide its MeasureValue (or MeasureValues in 
the case of data stored as an ordered array for each cell). The DataItems 
could override the MeasureValues (for example a cell with an alternate 
measure or perhaps containing an incomplete or misordered array)

***DataItem would not need to reference an alternate NCube as there would 
be no way to include a Cell that has no previously defined relationship to 
the NCube cells.


Wendy L. Thomas                          Phone: +1 612.624.4389
Data Access Core Director		 Fax:   +1 612.626.8375
Minnesota Population Center              Email: wlt at pop.umn.edu
University of Minnesota
50 Willey Hall
225 19th Avenue South
Minneapolis, MN 55455