> the most idiomatic way to handle this is to merge the objects in: > > obj = session.merge(existing_object) > > this will emit a SELECT for the existing row, then copy the state of > "existing_object" to an object located for that primary key, if found. > It ensures that the correct choice of "pending" or "persistent" is made > depending on if the row already exists. >
Thanks for your response Michael. It wasn't clear from my original post, but I am using merge to copy from PROD to DEV. My merge function looks something like this (simplified, but I'm copying multiple entities) session_dest.merge(entity) session_dest.commit() session_dest.expunge_all() # large object graphs were causing me to run low on memory, so I merge them one at a time and then clear the local cache. So, assuming DEV has a single record {acct_id: 1, env_id: 1} and I'm copying a record {acct_id: 1, env_id: 4} from PROD, it incorrectly thinks that this record should be INSERTed, when in fact there is a constraint (acct_id must be unique) that prevents this. The more I evaluate this, the more I think that correctly modeling the unique constraint will fix my problem. Then my before_update handler would function but would properly UPDATE the record. Shawn -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To view this discussion on the web visit https://groups.google.com/d/msg/sqlalchemy/-/9azvATgVSsoJ. To post to this group, send email to sqlalchemy@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.