Of Default Values and Ordered Views

Metakit Illuminati,

I would be pleased if you could share some of your
hard earned 
knowledge with me
by answering some of my questions about Metakit. But
first, some 
context. I am
working with a logically three-dimensional data set
(observations,objects,measurements). At each of
400-1200 observations, 
there is
a list of ~5000 objects each of which has 1-25
measurements recorded 
for that
observation. The tricky part is that the list of
objects varies from 
observation
to observation and the measurements taken on each
object varies from 
observation
to observation. For the most part, I will be building
the database once 
and then
reading it many times. An example:

observation1:
  object1: measurement1, measurement2
  object2: measurement3

observation2:
  object1: measurement1, measurement2
  object3: measurement1
  object4: measurement2, measurement3

The typical access pattern is to move from observation
to observation, 
visiting
a subset of objects and measurements at each
observation. One possible 
Metakit
schema would be:

View:
  observation1, subview1
  .
  .
  observation1200, subview1200

SubView:
  object1, measurement1, measurement2, ...,
measurement25
  .
  .
  object5000, measurement1, measurement2, ...,
measurement25

Where unavailable measurements are indicated by a
special value or 
there is a
boolean flag for each measurement.

Question 1: Is there a better schema?

It seems that using a special value would reduce the
storage 
requirements and
would be more computationally efficient as a result of
fewer property 
look ups.

Question 2: Is there a way to override the default
value of a property? 
Can I
safely replace c4_Handler::ClearBytes(c4_Bytes& buf_)
with my own 
custom version?

In order to quickly search a given observation for a
specified object, 
I would
like the subviews to be ordered, but it is not clear
to me how to 
create and
maintain order subviews. c4_View c4_View::Ordered(int)
returns a 
derived view
that provides a way of accessing the underlying view
such that it 
appears to be
ordered. I would rather that the underlying view
itself be maintained 
(and
stored) ordered so that I do not need to keep creating
ordered derived 
views.

Question 3: Is there a way to directly maintain a view
in order? If 
not, how can
I store the ordered view (so I don't need to recreate
it every time) 
and will it
be a resource hog?

Much thanks for any thoughts you may have on these
questions!

Thanks,
Alex


	
		
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