I rarely ever use them. When they have been used it was for constructing queries that use the derived column when building reports. It avoids having to bring in the objects into memory and compute the value to see if they meet the qualifier. However if the qualifier can be expressed using the non derived attributes I take that route instead.
Ricardo Parada > On Jan 12, 2016, at 7:09 PM, Theodore Petrosky <tedp...@yahoo.com> wrote: > > >> On Jan 12, 2016, at 4:41 PM, Paul Hoadley <pa...@logicsquad.net> wrote: >> >> Hi Ted, >> >>> On 13 Jan 2016, at 6:49 am, Theodore Petrosky <tedp...@yahoo.com> wrote: >>> >>> I have an Entity with a derived column. Entity Person, real attributes >>> firstName, lastName, derived column fullName firstName || ' ' || lastName. >>> >>> the derived column only shows up when I first run the app. when I add new >>> people, the derived column is blank. even login out and back in does >>> nothing. But when I stop the app and relaunch it, the derived column >>> resolves and I see what I expect. >> >> Derived attributes are computed by the database, and so only updated when >> the EO is fetched into memory. To update the derived attribute, you would >> need to cause the EO to be re-fetched from the database. >> >>> 1. should I go back to creating a method on Entity Person fullName that >>> returns a string concatenating first and last names? >> >> Probably, yes. > > OK, that’s a plan, when do you feel it’s appropriate to use a derived column? > >> >> >> -- >> Paul Hoadley >> http://logicsquad.net/ > > > _______________________________________________ > 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/rparada%40mac.com > > This email sent to rpar...@mac.com _______________________________________________ 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
