- The "polymorphic discriminator" column may be part of a

primary key, and it will be populated with the correct
discriminator value.  [ticket:1300]

2 files changed, 5 insertions, 5 deletions

diff --git a/lib/sqlalchemy/orm/mapper.py b/lib/sqlalchemy/orm/mapper.py
index 87c4c8100..b84f0166a 100644
--- a/lib/sqlalchemy/orm/mapper.py
+++ b/lib/sqlalchemy/orm/mapper.py
@@ -1297,10 +1297,6 @@ class Mapper(object):
                     for col in mapper._cols_by_table[table]:
                         if col is mapper.version_id_col:
                             params[col.key] = 1
-                        elif col in pks:
-                            value = mapper._get_state_attr_by_column(state, col)
-                            if value is not None:
-                                params[col.key] = value
                         elif mapper.polymorphic_on and mapper.polymorphic_on.shares_lineage(col):
                             if self._should_log_debug:
                                 self._log_debug("Using polymorphic identity '%s' for insert column '%s'" % (mapper.polymorphic_identity, col.key))
@@ -1309,6 +1305,10 @@ class Mapper(object):
                                  col.server_default is None) or
                                 value is not None):
                                 params[col.key] = value
+                        elif col in pks:
+                            value = mapper._get_state_attr_by_column(state, col)
+                            if value is not None:
+                                params[col.key] = value
                         else:
                             value = mapper._get_state_attr_by_column(state, col)
                             if ((col.default is None and
diff --git a/lib/sqlalchemy/sql/expression.py b/lib/sqlalchemy/sql/expression.py
index 859419022..65c3c2135 100644
--- a/lib/sqlalchemy/sql/expression.py
+++ b/lib/sqlalchemy/sql/expression.py
@@ -1587,7 +1587,7 @@ class ColumnElement(ClauseElement, _CompareMixin):
     def shares_lineage(self, othercolumn):
         """Return True if the given ``ColumnElement`` has a common ancestor to this ``ColumnElement``."""
 
-        return len(self.proxy_set.intersection(othercolumn.proxy_set)) > 0
+        return bool(self.proxy_set.intersection(othercolumn.proxy_set))
 
     def _make_proxy(self, selectable, name=None):
         """Create a new ``ColumnElement`` representing this