[Developers] MQL index property

[David Flanagan]

In MQL I can use the index pseudo-property to sort things into their 
natural order.  I know that this works to sort tracks on an album into 
the order in which they are recorded, for example. If I examine the 
index of albums by a band, I find that some albums have indexes and some 
do not. The indexes seem to correspond to release order of the albums, 
but I don't know if this is true in general.

Can anyone provide other examples of useful orderings?  Is there any 
programmatic way to find out what properties are ordered and what the 
ordering represents?  Or does this simply come down to a schema 
documentation issue?

	David