- Primary key values can now be changed on a joined-table inheritance

object, and ON UPDATE CASCADE will be taken into account when
the flush happens.  Set the new "passive_updates" flag to False
on mapper() when using SQLite or MySQL/MyISAM. [ticket:1362]

- flush() now detects when a primary key column was updated by
an ON UPDATE CASCADE operation from another primary key, and
can then locate the row for a subsequent UPDATE on the new PK
value.  This occurs when a relation() is there to establish
the relationship as well as passive_updates=True.  [ticket:1671]

1 files changed, 11 insertions, 1 deletions

diff --git a/lib/sqlalchemy/orm/sync.py b/lib/sqlalchemy/orm/sync.py
index 8826ab3aa..8a30a9e62 100644
--- a/lib/sqlalchemy/orm/sync.py
+++ b/lib/sqlalchemy/orm/sync.py
@@ -10,7 +10,8 @@ based on join conditions.
 
 from sqlalchemy.orm import exc, util as mapperutil
 
-def populate(source, source_mapper, dest, dest_mapper, synchronize_pairs):
+def populate(source, source_mapper, dest, dest_mapper, 
+                        synchronize_pairs, uowcommit, passive_updates):
     for l, r in synchronize_pairs:
         try:
             value = source_mapper._get_state_attr_by_column(source, l)
@@ -21,6 +22,15 @@ def populate(source, source_mapper, dest, dest_mapper, synchronize_pairs):
             dest_mapper._set_state_attr_by_column(dest, r, value)
         except exc.UnmappedColumnError:
             _raise_col_to_prop(True, source_mapper, l, dest_mapper, r)
+        
+        # techically the "r.primary_key" check isn't
+        # needed here, but we check for this condition to limit
+        # how often this logic is invoked for memory/performance
+        # reasons, since we only need this info for a primary key
+        # destination.
+        if l.primary_key and r.primary_key and \
+                    r.references(l) and passive_updates:
+            uowcommit.attributes[("pk_cascaded", dest, r)] = True
 
 def clear(dest, dest_mapper, synchronize_pairs):
     for l, r in synchronize_pairs: