Re: Feeler for SML (Simple Markup Language)
Leigh Dodds wrote: > I'd have said an e-commerce app would have been an all or nothing application. > Transactions should be atomic. Yes, it is precisely the e-commerce *app* which should be all-or-nothing *on its own terms*. That is, a particular process defined and executed at the receiving node either will, or will not, have all of the input data it requires. The definition of that data requirement is local: the sending node supplies data, presumably conforming to a definition which makes sense to the sender, but is not entitled to specify for the receiver the particular definition either of the data or of the processes to be performed on it. And, yes, transactions should be atomic but, again, on their own terms. The atomicity of the transaction is only from the point of view of the (receiving) node which executes it. From the point of view of the node sending the data which triggers a remote transaction, the 'atomic' transaction may well include (and in the execution of trades in securities--the example you use below--nearly always does include) several such remote pieces. > If I sent you an e-commerce order, and I've accidentally (or mistakenly) sent you my company > name in an external entity, what will you do with the order. Buy in the stock, but have > nowhere to ship/charge it? What if I've incorrectly coded the amount of stock I want - how > much will you send/charge me? Let's make these examples real. Execution of orders in securities does not occur in a vacuum. In order to accept an order to deal on your behalf, or to deal with you as principal, I must know enough about you to be able to confirm, compare and settle the transaction. It's not merely that I can't execute the trade if I don't know your company name: I can't execute it even with your company name if I do not know your confirmation and settlement details. In other words, to get to the point where you can send me an order for execution, we have already gone through significant exchanges of data, to establish the context in which that trade, legally as well as logistically, might be executed.If after all that you neglect on one occasion to send your name with the order, then if I know the provenance of the message I already know who you are, and I can supply the missing data. If the data missing on that occasion is a crucial detail particular to that trade (see your objections just below) then, because I know who you are (from context previously established) and know the provenance of the message you have sent me, I can (programmatically, from my processor) send you a message requesting the missing details which I require to consummate the transaction. > What if that detail is the whole point of the transaction? What useful information is left? > How do you decide how incomplete the document/message/fragment can be before the transaction > becomes useless? Do you have to apply heuristics to determine which bits of data are > relevant/fail-safe? > > If some 'detail' is irrevelant then why is it being sent in the first place? Irrelevant to the receiver, and to the processes which the receiver can perform, does not mean irrelevant to the sender. > You can therefore prune your protocol further. Or, my protocol could be to derive the schema on every occasion from the data as actually received and as instantiated within the context of locally-defined processes which the sender may know nothing of. > All or nothing is at least safe. Unfortunately, it is safely nothing if we cannot process the very transactions which we went into business to execute. Respectfully, Walter Perry xml-dev: A list for W3C XML Developers. To post, mailto:xml-dev@i... Archived as: http://www.lists.ic.ac.uk/hypermail/xml-dev/ and on CD-ROM/ISBN 981-02-3594-1 To unsubscribe, mailto:majordomo@i... the following message; unsubscribe xml-dev To subscribe to the digests, mailto:majordomo@i... the following message; subscribe xml-dev-digest List coordinator, Henry Rzepa (mailto:rzepa@i...)
PURCHASE STYLUS STUDIO ONLINE TODAY!
Purchasing Stylus Studio from our online shop is Easy, Secure and Value Priced!
Download The World's Best XML IDE!
Accelerate XML development with our award-winning XML IDE - Download a free trial today!
Subscribe in XML format