Re: [Glorp-development] Duplicate key question - smallwiki

30 May 2007

Thanks for the responses. I did get this to work by using one session  
for reading the nested object and registering the new object. One of  
the situations where another session's objects would be nice to use  
is that rarely changed nested objects could be cached in memory  
rather than running another query. Glorp is efficient enough that I  
should worry about such things, but old habits die hard :)

Brian.

On May 30, 2007, at 6:31 AM, Alan Knight wrote:

...
  I don't quite know why this would be happening,
partly because I  
 don't know the MagritteGlorp package, so I'm not sure what some of  
 these calls are doing. My guess is that it is because you're using  
 two different sessions. In general, it's a very bad idea to mix  
 objects between two different sessions. Glorp relies on knowing  
 whether or not it read the object from the database in order to  
 know whether to do an insert or an update. If you read objA in one  
 session, then give it to another session as if it were a new  
 object, it will probably try to insert it and cause an error. If  
 you did this in the same session, I'd expect it to work. Certainly  
 that sort of thing works fine in basic Glorp.

 At 01:02 AM 5/30/2007, Brian Murphy-Dye wrote:
  I'm using Ramon Leon's MagritteGlorp
package, which ties together the
 extremely useful Magritte and Glorp packages, but must not be using
 it quite correctly. When registering an object that has a reference
 to an already stored object, it seems to attempt re-insert the
 referenced object. For example:

 objA := ADescriptorSystem getSession execute: (A find where [:ea | ea
 name = 'hello']).
 objB := B new.
 objB a: objA.
 session := B getSession.
 session beginUnitOfWork.
 objB register: objB.
 session commitUnitOfWork.

 raises a 'GlorpDatabaseWriteError: ERROR: duplicate key violates
 unique constraint' error. I thought it might be because I am using
 one session to load the object and another session to register, but
 believe I've also tried doing everything in one session. If it is of
 any help, the reference description is of type
 MAToOneRelationDescription. On another project, I tried
 MAMultipleOptionDescription with the same error. Any ideas on how to
 make it recognize the object is already stored and hasn't changed?

 Thanks, Brian.

 Glorp.rjl.8
 GlorpPostload-rjl.3
 GlorpPreload-rjl.2
 Magritte-Seaside-lr.228.mcz
 Magritte-Model-lr.266
 MagritteGlorp-rjl.47

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 Alan Knight [|], Cincom Smalltalk Development
 knight(a)acm.org
 aknight(a)cincom.com
 http://www.cincom.com/smalltalk

 "The Static Typing Philosophy: Make it fast. Make it right. Make it  
 run." - Niall Ross 