Jeff, On 18. 3. 2016, at 17:42, Jeff Schmitz <jeffschm...@icloud.com> wrote:
> ... I’ve got some lock trimming to do. Depending on your application logic, you might get away with locking primary keys only, nothing else. I have got one application where it so happens nobody cares of possible clashes, the desired logic is that the latest writer wins; I am locking primary keys only in its model, and it runs without any problem (at least, any I know of ;)) for years. Note also, with some databases it might get a bit hairy locking timestamps -- sometimes, they might slightly change just by storing in the DB. And of course, you (almost) never want to lock BLOBs. All the best, OC > >> On Mar 18, 2016, at 11:11 AM, Chuck Hill <ch...@gevityinc.com> wrote: >> >> Hi Jeff, >> >> Yes, if a column is not marked as locking, then it won’t appear in the WHERE >> clause. >> >> The danger is that you might save changes that are inconsistent with what >> the database has stored in the columns that you are not locking on. As a >> contrived example, consider the update below changing Bob to Robert. If you >> don’t lock on first and last name, some other process might have updated >> both names to John Edwards. Your update will now change the name to Robert >> Edwards. You need to look at your data and see where that might matter and >> where it does not. >> >> Chuck >> >> >> From: <webobjects-dev-bounces+chill=gevityinc....@lists.apple.com> on behalf >> of Jeff Schmitz <jeffschm...@icloud.com> >> Date: Thursday, March 17, 2016 at 5:20 PM >> To: WebObjects Development <webobjects-dev@lists.apple.com> >> Subject: Quick EOModel Column Locking ? >> >> I’m starting to get some optimistic column locking failures during >> background db processing soI’m trying to grasp conditions under which I >> don’t need to lock a column (i.e. put the little lock symbol in EOModeler) >> >> If I have a column in a table that I know is not updated (i.e. changed) by >> any client except form my personal administrative page, can I get away >> without locking that column? On unlocked columns is there any where >> clause checks such as shown below before that column is updated? If not, >> this should stop the locking errors, right? Any other dangers with this? >> >> update Person set FirstName = 'Robert' where PersonID = 123 and FirstName = >> 'Bob' and LastName = 'Roberts' >> Finally, to make this change Is it as simple as unchecking the column and >> redeploying my EOModel file? >> >> Thanks! >> Jeff > > _______________________________________________ > 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/ocs%40ocs.cz > > This email sent to o...@ocs.cz _______________________________________________ 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
