Re: Parent/Child Insert ordering (was: Caching problem?)

[Borut Bolčina]

Hi, in API docs for org.objectstyle.cayenne.map.AshwoodEntitySorter it says: "...Presently it works for acyclic database schemas with possible multi-reflexive tables. The class uses topological sorting from the Ashwood library." What are multi-reflexive tables? I guess not every reflexive relationship is cyclic. If db row "points" to the same db row then it would be cyclic (for example - someone is his/her own manager), otherwise just reflexive. Is this correct? -Borut On 21.5.2006 19:24, Andrus Adamchik wrote: Cayenne handles correct ordering of operations automatically, based on dependencies derived from relationships.The algorithm has a few limitations though. It can't handle cycles (when Entity A depends on Entity B, but also Entity B depends on Entity A). This probably also includes entities that have relationships to the same entity (I assume this is the case the original post was referring to). There are few solutions: 1. (a workaround, rather than a solution) Do commit in two steps. 2. Define FK constraints in question as DEFERRABLE and INITIALLY DEFERRED (supported by Postgres 8.*) 3. Set a custom org.objectstyle.cayenne.map.EntitySorter on the DataNode. Andrus On May 20, 2006, at 3:00 AM, Marcin Skladaniec wrote: Hm. Strange. I do really complex commits, sometimes 7 or more related records (I mean 7 levels of relationship, not seven entities), related by many-to-many many-to-one relationships and never get those problems. And it doesn't matter if the records are new or old. Could you describe how you are creating objects and how do you commit them ? Regards Marcin On 20/05/2006, at 4:31 PM, Tomi NA wrote: On 5/20/06, Jeff de Vries <[EMAIL PROTECTED]> wrote: I don't know if it is related or not, but I've also had problems in the past when I try to create a new parent and several child objects related to that parent all at once and then try to commit.  The problem looks like Cayenne is INSERTing the child records into the database first, before the parent record, and the database complains that the children have an invalid foreign key (and, yes, I have the ON UPDATE and ON DELETE rules for the foreign key set to DO NOTHING and I still get the error from PostgreSQL).  To get around it I just committed the parent first, then committed all the children. I had the same problem, IIRC: I was very surprised that cayenne couldn't handle such a commit, although truth be told, I can't imagine everything that's going on under the hood of the operation that would make implementing this feature difficult. I would certainly love to see this fixed (if at all possible) as I wasn't to happy to have to commit in the middle of what had to be an atomic transaction. It'd also make the framework a lot more flexible, e.g. enabling the user to have long inter-commit sessions with complex data updates, if the user so desires. t.n.a. -- -- Naključna izjava tedna iz tednika Mladina: