On Feb 20, 2015, at 12:09 PM, OC <o...@ocs.cz> wrote: > it must pass a slightly more complex test than uniqueness: > > - when inserted into PRICE_OFFERS table, > - the newly inserted object must have value in column PRICE, which is higher, > - than any (max) of the already existing objects in that table, which > - have YES in a boolean column VALID, and > - at the same moment, have same value in AUCTION_ID column as the inserted > object. > > (In fact the real condition is even more complex, but this is the gist of it: > consider an auction system, where a new bid added to a particular auction > must be higher than all previous valid bids for the same auction.) > > Nevertheless, I believe that when we are pursuing the > implement-the-behaviour-at-the-application-level way (unlike the check > restraint at the DB level), the particular TEST is actually irrelevant. The > gist is that it must not be possible to store an object which does not pass > TEST -- whatever the TEST tests.
Why is this a requirement? If highest price wins, then you only need to select the max price row where price offer date is less than auction end. If a few offers get thrown in there out of order, how does that break anything? > > See please again the [1] above -- the code must make sure that > > (a) when TESTing, the participating objects are a proper snapshot of database > contents of some moment in the past > (b) when saving, the code must make sure that if the values of the snapshot > did change, the saving won't happen > > That should be sufficient, should it not? > > Does it make sense? > > Thanks a lot, > OC > _______________________________________________ Do not post admin requests to the list. They will be ignored. Webobjects-dev mailing list (Webobjects-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/webobjects-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
