The upshot is that it's not possible to get this data in after_flush
> without the load occurring ahead of time. So add a before_flush() method
> that iterates through everything and loads all collections you care about,
> then they should be present by the time you get to after_flush().
Ok, I have to look into the before_flush event to make sure I have enough
info to target only updated instances. e.g. If there are 1,000 books in the
session, and one chapter gets moved between 2 of them, I don’t want to load
the chapters relationship of all books in before_flush.
Alternately, I might be able to do what I need to do if I can get the value
of chapter.book or chapter.book_id prior to the flush. load_history() tells
me the value that’s about to be flushed: how do I get the original value?
In case you’re interested, what I’m trying to do is write a tool which
syncs a RDBMS with a document store. The user defines Collections, which
specify columns and nested relationships which should be persisted. For
example:
class BookCollection(DocumentCollection):
model = Book
name = "books"
included_relations = [
'publisher', 'publisher/links', 'publisher/tags', 'extra_info',
'chapters', 'authors', 'tags', 'categories']
excluded_fields = [
'authors/email', 'summary']
The tool uses these documents to watch for updates to certain
relationships. That’s why, in this case, I want to view the chapter
relationship change from a Book-centric perspective.
Thanks again for all the help.
chad.
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