setas01@cai.com (08/22/90)
In one of the postings gordon@mead.UUCP (Gordon Edwards) writes: > No one is questioning the ability to create a view containing a UNION. Can > the view be updated is the question. My impression from the first posting was that some databases do not permit UNIONs in view definitions. > My previous post argues the case from a logical point of view. To be > updatable, the INSERT, UPDATE, and DELETE operations have to be defined. If > the view is created with a UNION, which table will a tuple be inserted? Yes, if the view consists of ONE table, CA-DB ** does ** permit an update. ( not if the view consists of more than one table ) I doubt if any vendor permits updateble views. Ashok Sethi Standard Disclaimer : " The views expressed are mine and not of my employer. "
nigelc@cognos.UUCP (Nigel Campbell) (08/28/90)
In article <330.26d1980a@cai.com> setas01@cai.com writes: >In one of the postings gordon@mead.UUCP (Gordon Edwards) writes: [stuff deleted] > > Yes, if the view consists of ONE table, CA-DB ** does ** permit an update. > ( not if the view consists of more than one table ) I doubt if any vendor > permits updateble views. > Starbase from Cognos and Interbase from Interbase Corp allow multi-table views to updated . To achieve this you define triggers for the view that perform the relevant store,modify,erase rules that you want to have applied . Rdb/Vms supports triggers alos but I am not sure if it can support a similar concept . -- Nigel Campbell Voice: (613) 783-6828 P.O. Box 9707 Cognos Incorporated FAX: (613) 738-0002 3755 Riverside Dr. uucp: nigelc@cognos.uucp || uunet!mitel!sce!cognos!nigelc Ottawa, Ontario CANADA K1G 3Z4