On 2011-11-09, at 4:08 PM, Paul Hoadley wrote: > On 10/11/2011, at 8:25 AM, Ramsey Gurley wrote: > >>> Say I have two entities, User and Role, and a joining entity UserRole to >>> create a many-to-many relationship between them. So I have a relationship >>> 'userRoles' from User to UserRole (and a relationship 'userRoles' from Role >>> back to UserRole). I flatten the relationship on User, so I also have a >>> 'roles' relationship on that entity.
So User.userRoles and Role.userRoles are not class attributes, right? They are just modelled. User.roles and Role.users are the to-many relationships that you see in the Java code. >>> Say I delete a User. I want User.userRoles to Cascade. And I want both >>> UserRole.user and UserRole.role to Nullify. And at that point, isn't the >>> work done? So in this case, wouldn't I want No Action on User.roles? And >>> hence isn't this a counter-example to your advice above? (It may well not >>> be—tell me if I'm wrong!) This is making my head hurt. I have the public to-many User.roles as Nullify. I was under the impression that you needed that to remove that User from the Role.users relationship. But I could be wrong. That might just be a habit. The non-class attribute User.userRoles is set to Cascade. The to-one relationships from UserRole to User and to Role is Nullify. >> >> I looked a second time. The cascade is actually on the non-class property. >> The flattened is nullify... so maybe it would work with no action. I'm not >> recommending anything, just noting something I saw which seemed odd. > > Sorry, not trying to pin you down to anything! In my example above, because > UserRole.role is Nullify, probably having User.roles set to Nullify would not > make any difference. I would have to work a bit hard to contrive an example > where it mattered. Say if UserRole.role was Cascade (obviously it wouldn't > be)—then if User.roles was Nullify they would conflict, but if it was No > Action, the Cascade would happen. > > Obviously you could look at each flattened relationship on a case-by-case > basis. I'm just trying to tease out whether No Action would be correct 100% > of the time, as long as you had the right delete rules along the chain of > actual relationships that constituted the flattened relationship. > -- Chuck Hill Senior Consultant / VP Development Practical WebObjects - for developers who want to increase their overall knowledge of WebObjects or who are trying to solve specific problems. http://www.global-village.net/products/practical_webobjects _______________________________________________ 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: http://lists.apple.com/mailman/options/webobjects-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
