- From: <paul.downey@bt.com>
- Date: Wed, 3 Mar 2004 17:04:47 -0000
- To: <dbooth@w3.org>, <bparsia@isr.umd.edu>
- Cc: <www-ws-desc@w3.org>, <dorchard@bea.com>, <distobj@acm.org>
David Booth wrote: > IMO, this is the main reason >relational databases won the database wars 20 years ago when they were > introduced: you can easily add new tables (i.e., new relations) to a > relational database without breaking existing application code. > However, > if you add new data to an XML schema for a tree-structured data format (for > example by inserting siblings or by inserting new levels of hierarchy) you > are much more likely to break existing application code. It is possible to > avoid, but it's harder than in the relational world. i do like the analogy with relational (v) hierarchical databases, but one view of an RDBMS is as a loosely connected graph with joins between columns and views. I agree, the success of relational databases was in no small part due to their making touchless versioning possible - the query language /by default/ ignores new columns and tables, and missing data can be easily recognised and given a default value. Paul
Received on Wednesday, 3 March 2004 12:05:20 UTC