Performance improvement for xml loads (+comments)

[Al Snell]

On 7 Dec 2000, Derek Atkins wrote:

> I admit that I don't know very much about DBMS systems.  Are columns
> in a table labeled?  And can you arbitrarily add a new column to an
> existing table (I suppose you could create a new table with the
> existing column information and add the new column, then destroy the
> old table and rename the new table back to the old one).  I just want
> to make sure that you're not dependent upon a particular column
> position for data.  (Again, I know next to nothing about DBMS or SQL).

Yep, columns are labelled, but that's just the same as the fact that nodes
are labelled in XML... a label is a label, meaning that uncreognised
labels can either be ignored or flagged as errors; however, there is still
no way for code to know if an unrecognised tag/column is something it can
safely ignore or a flag indicating that the data fields are encrypted!

Extensibility of a storage format is much more than just providing a
structure that does not require detailed format knowledge to parse - IFF,
XML, SQL tables, and CSV files with column headers in the first row all
provide this. PNG uses an IIF-like chunked format with flags on each chunk
specifying how they should be handled by code that does not understand
them; that's the only example of format extensibility I've seen yet.

ABS