xml-dev - Re: updategrams

[Rick JELLIFFE <ricko@geotempo.com>]

> 
> > 2. anyone can give a rundown on why they went for a diff technique
> > rather than a direct pat specification with a replacement value?

No but here is a different approach that may be of interest.

For a commercial client I implemented a system that just used a dirty
flag on
elements (and attribute giving clean/dirty/new.) Their requirement was
in a similar area to updategrams: they needed to extract trees from a
database, update sections and then they just wanted the updated elements
only merged into the database.

Because we used column=attribute conventions for the database
XMLification, the dirty bit was in fact dirty rows not dirty fields: for
their application the coarse-grain approach was fine. It seemed out that
pruning the XML data of empty data values (or data=(number)0, or null)
was easier for performance (they had lots of unused columns) from the
user perspective than fine-grained update, but I don't expect that is a
general rule.

This is not nearly as sophisticated as the updategrams, of course, but
it works well as far as it goes.

Rick Jelliffe