- Added a new type-level modifier :meth:`.TypeEngine.evaluates_none`

which indicates to the ORM that a positive set of None should be
persisted as the value NULL, instead of omitting the column from
the INSERT statement.  This feature is used both as part of the
implementation for :ticket:`3514` as well as a standalone feature
available on any type.  fixes #3250
- add new documentation section illustrating the "how to force null"
 use case of #3250
- alter our change from #3514 so that the class-level flag is now
called "should_evaluate_none"; so that "evaluates_none" is now
a generative method.

1 files changed, 2 insertions, 2 deletions

diff --git a/lib/sqlalchemy/orm/mapper.py b/lib/sqlalchemy/orm/mapper.py
index 21577f5ea..5ade4b966 100644
--- a/lib/sqlalchemy/orm/mapper.py
+++ b/lib/sqlalchemy/orm/mapper.py
@@ -1921,7 +1921,7 @@ class Mapper(InspectionAttr):
                 table,
                 frozenset(
                     col.key for col in columns
-                    if col.type.evaluates_none
+                    if col.type.should_evaluate_none
                 )
             )
             for table, columns in self._cols_by_table.items()
@@ -1936,7 +1936,7 @@ class Mapper(InspectionAttr):
                     col.key for col in columns
                     if not col.primary_key and
                     not col.server_default and not col.default
-                    and not col.type.evaluates_none)
+                    and not col.type.should_evaluate_none)
             )
             for table, columns in self._cols_by_table.items()
         )