On Tuesday, 25 August 2015 11:23:51 UTC+10, Alex Fraser wrote:
>
> Is there a declarative way to add foreign keys to the history table when
> using history_meta.py? In the app I'm making the user can view old versions
> of a document, and I want to make sure e.g. the user that created the old
> version can't be deleted while their old versions exist.
>
For what it's worth, we have solved this by checking for a 'version' flag
in the info attribute of foreign key constraints:
diff --git a/history_meta.py b/history_meta.py
index f1e308e..da72f27 100644
--- a/history_meta.py
+++ b/history_meta.py
@@ -117,6 +117,16 @@ def _history_mapper(local_mapper):
*cols,
schema=local_mapper.local_table.schema
)
+
+ for fk in local_mapper.local_table.foreign_key_constraints:
+ log.debug(
+ "Duplicating foreign key for history table: %s, fk: %s",
+ local_mapper.local_table, fk)
+ if 'version' in fk.info and fk.info['version']:
+ fk_new = fk.copy()
+ fk_new.info['history_copy'] = fk
+ table.append_constraint(fk_new)
+
else:
# single table inheritance. take any additional columns that may
have
# been added and add them to the history table.
Let me know if this is too dodgy :)
Cheers,
Alex
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