Hi Patrick,Thanks for providing a solution you have it working. But having a new field for maintaining the order of records like "sortOrder" in the entity/ table has various other benefits as affirmed by Chuck, Mike, et al.,
Thank You, Shravan Kumar. M -------------------------------- Mon Nov 2 15:39:00 2009 From: "Patrick Middleton" <patr...@onestep.co.uk> To: "Development WebObjects" <webobjects-dev@lists.apple.com> On 1 Nov 2009, at 12:40, Shravan Kumar. M wrote: > Thanks Kieran for your solution. But unfortunately, we don't extend ERXGenericRecord, so we cannot get benefits of this!!! I have actually read about your this solution in a similar kind of issue posted and responded by you here: http://www.mail-archive.com/webobjects-dev@lists.apple.com/msg25975.html > > From: Kieran Kelleher <kieran_li...@mac.com> > To: Shravan Kumar. M <mshravan_...@yahoo.com> > Cc: Chuck Hill <ch...@global-village.net>; WO Dev Group > <webobjects-dev@lists.apple.com> > Sent: Sun, November 1, 2009 5:55:25 PM > Subject: Re: how to insert records in database in the order of insertion to EC > > Or if you want the order of the PKs to be the same order as your insertion > into the EC, you can try calling > > eo.primaryKeyInTransaction (or sth like that) > > which is provided by ERXGenericRecord subclass. > > That method assigned the PK ....... do it in each iteration. Then the items are saved the the PK order the same as insertion order. > > Regards, Kieran I'm still working with WO451, so I'm not going to post my code. I encountered a problem very much like this one: primary keys were also being used as audit sequence IDs, and this made ensuring that the order of insertion into an editing context and ascending order of primary keys be the same essential. The fix I chose was broadly as follows (and as far as I can tell should work in 5.x, and I'm looking at the 5.3 Javadocs that I have to hand.) I created an instance of a helper object class; one member variable is the editing context of interest. The editing context at this point has no unsaved changes. The helper implements EOObserving, and on cue -- startWatching() -- registers itself as an observer with an EOObserverCenter. When the helper receives objectWillChange(Object object), it tests object to see if [1] its editing context is the helper's editing context [2] its EOGlobalID returns true for isTemporary() and [3] whether the object is already in an array/vector/whatever other ordered collection is being maintained by the helper -- if not, it adds it. At some point -- stopWatching() -- we then unregister the helper from the EOObserverCenter, and ask the helper for its collection. We can then examine the collection to see what primary keys we need to generate, generate them, and cache them somewhere -- I have a singleton class to be the default delegate for all EODatabaseContexts which implements databaseContextNewPrimaryKey(EODatabaseContext dbCtxt, Object object, EOEntity entity). When I call save() on the editingContext, EOF will insert objects into the database as normal, except the pre-created primary keys will be assigned to the intended objects and in the correct order. --- Regards Patrick OneStep Solutions (Research) LLP www.onestep.co.uk
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