- changelog and migration for #3188, #3148.

fixes #3188
fixes #3148

diff --git a/doc/build/changelog/changelog_10.rst b/doc/build/changelog/changelog_10.rst
index 55a2756598e67ad1908a394009da3a63548f548d..cb7a9088dc61848ecd057ff525fbaf5c1e966abf 100644 (file)
--- a/doc/build/changelog/changelog_10.rst
+++ b/doc/build/changelog/changelog_10.rst
@@ -21,6 +21,33 @@
     series as well.  For changes that are specific to 1.0 with an emphasis
     on compatibility concerns, see :doc:`/changelog/migration_10`.
 
+    .. change::
+        :tags: bug, orm
+        :tickets: 3148, 3188
+
+        A major rework to the behavior of expression labels, most
+        specifically when used with ColumnProperty constructs with
+        custom SQL expressions and in conjunction with the "order by
+        labels" logic first introduced in 0.9.  Fixes include that an
+        ``order_by(Entity.some_col_prop)`` will now make use of "order by
+        label" rules even if Entity has been subject to aliasing,
+        either via inheritance rendering or via the use of the
+        ``aliased()`` construct; rendering of the same column property
+        multiple times with aliasing (e.g. ``query(Entity.some_prop,
+        entity_alias.some_prop)``) will label each occurrence of the
+        entity with a distinct label, and additionally "order by
+        label" rules will work for both (e.g.
+        ``order_by(Entity.some_prop, entity_alias.some_prop)``).
+        Additional issues that could prevent the "order by label"
+        logic from working in 0.9, most notably that the state of a
+        Label could change such that "order by label" would stop
+        working depending on how things were called, has been fixed.
+
+        .. seealso::
+
+            :ref:`bug_3188`
+
+
     .. change::
         :tags: bug, mysql
         :tickets: 3186

diff --git a/doc/build/changelog/migration_10.rst b/doc/build/changelog/migration_10.rst
index 2b9e5f0fd59d188fb682cfc2778b46d6a113daf7..6a48b31fa284d441aa1f61aa73270435740b1c17 100644 (file)
--- a/doc/build/changelog/migration_10.rst
+++ b/doc/build/changelog/migration_10.rst
@@ -8,7 +8,7 @@ What's New in SQLAlchemy 1.0?
     undergoing maintenance releases as of May, 2014,
     and SQLAlchemy version 1.0, as of yet unreleased.
 
-    Document last updated: September 1, 2014
+    Document last updated: September 7, 2014
 
 Introduction
 ============
@@ -307,6 +307,86 @@ Renders::
 
 :ticket:`3177`
 
+
+.. _bug_3188:
+
+ColumnProperty constructs work a lot better with aliases, order_by
+-------------------------------------------------------------------
+
+A variety of issues regarding :func:`.column_property` have been fixed,
+most specifically with regards to the :func:`.aliased` construct as well
+as the "order by label" logic introduced in 0.9 (see :ref:`migration_1068`).
+
+Given a mapping like the following::
+
+       class A(Base):
+           __tablename__ = 'a'
+
+           id = Column(Integer, primary_key=True)
+
+       class B(Base):
+           __tablename__ = 'b'
+
+           id = Column(Integer, primary_key=True)
+           a_id = Column(ForeignKey('a.id'))
+
+
+       A.b = column_property(
+               select([func.max(B.id)]).where(B.a_id == A.id).correlate(A)
+           )
+
+A simple scenario that included "A.b" twice would fail to render
+correctly::
+
+       print sess.query(A, a1).order_by(a1.b)
+
+This would order by the wrong column::
+
+       SELECT a.id AS a_id, (SELECT max(b.id) AS max_1 FROM b
+       WHERE b.a_id = a.id) AS anon_1, a_1.id AS a_1_id,
+       (SELECT max(b.id) AS max_2
+       FROM b WHERE b.a_id = a_1.id) AS anon_2
+       FROM a, a AS a_1 ORDER BY anon_1
+
+New output::
+
+       SELECT a.id AS a_id, (SELECT max(b.id) AS max_1
+       FROM b WHERE b.a_id = a.id) AS anon_1, a_1.id AS a_1_id,
+       (SELECT max(b.id) AS max_2
+       FROM b WHERE b.a_id = a_1.id) AS anon_2
+       FROM a, a AS a_1 ORDER BY anon_2
+
+There were also many scenarios where the "order by" logic would fail
+to order by label, for example if the mapping were "polymorphic"::
+
+       class A(Base):
+           __tablename__ = 'a'
+
+           id = Column(Integer, primary_key=True)
+           type = Column(String)
+
+           __mapper_args__ = {'polymorphic_on': type, 'with_polymorphic': '*'}
+
+The order_by would fail to use the label, as it would be anonymized due
+to the polymorphic loading::
+
+       SELECT a.id AS a_id, a.type AS a_type, (SELECT max(b.id) AS max_1
+       FROM b WHERE b.a_id = a.id) AS anon_1
+       FROM a ORDER BY (SELECT max(b.id) AS max_2
+       FROM b WHERE b.a_id = a.id)
+
+Now that the order by label tracks the anonymized label, this now works::
+
+       SELECT a.id AS a_id, a.type AS a_type, (SELECT max(b.id) AS max_1
+       FROM b WHERE b.a_id = a.id) AS anon_1
+       FROM a ORDER BY anon_1
+
+Included in these fixes are a variety of heisenbugs that could corrupt
+the state of an ``aliased()`` construct such that the labeling logic
+would again fail; these have also been fixed.
+
+:ticket:`3148` :ticket:`3188`
+
 .. _behavioral_changes_orm_10:
 
 Behavioral Changes - ORM