From: Mike Bayer <mike_mp@zzzcomputing.com>
Date: Tue, 4 Dec 2007 17:06:55 +0000 (+0000)
Subject: - relaxed rules on column_property() expressions having labels; any
X-Git-Tag: rel_0_4_2~113
X-Git-Url: http://git.ipfire.org/gitweb/gitweb.cgi?a=commitdiff_plain;h=cb46ae4fe97d364e8a160b6114519f125432c1e8;p=thirdparty%2Fsqlalchemy%2Fsqlalchemy.git

- relaxed rules on column_property() expressions having labels; any
ColumnElement is accepted now, as the compiler auto-labels non-labeled
ColumnElements now.  a selectable, like a select() statement, still
requires conversion to ColumnElement via as_scalar() or label().
---

diff --git a/CHANGES b/CHANGES
index a785ac1a97..e3ce282cfb 100644
--- a/CHANGES
+++ b/CHANGES
@@ -33,6 +33,11 @@ CHANGES
      version_id_col is typically set on the base mapper in an inheritance
      relationship where it takes effect for all inheriting mappers. 
      [ticket:883]
+   
+   - relaxed rules on column_property() expressions having labels; any
+     ColumnElement is accepted now, as the compiler auto-labels non-labeled
+     ColumnElements now.  a selectable, like a select() statement, still
+     requires conversion to ColumnElement via as_scalar() or label().
      
    - several ORM attributes have been removed or made private:
      mapper.get_attr_by_column(), mapper.set_attr_by_column(), 
diff --git a/lib/sqlalchemy/orm/properties.py b/lib/sqlalchemy/orm/properties.py
index 806c91a2b7..8980a4498a 100644
--- a/lib/sqlalchemy/orm/properties.py
+++ b/lib/sqlalchemy/orm/properties.py
@@ -12,7 +12,7 @@ to handle flush-time dependency sorting and processing.
 """
 
 from sqlalchemy import sql, schema, util, exceptions, logging
-from sqlalchemy.sql import util as sql_util, visitors, operators
+from sqlalchemy.sql import util as sql_util, visitors, operators, ColumnElement
 from sqlalchemy.orm import mapper, sync, strategies, attributes, dependency
 from sqlalchemy.orm import session as sessionlib
 from sqlalchemy.orm import util as mapperutil
@@ -38,10 +38,8 @@ class ColumnProperty(StrategizedProperty):
         self.comparator = ColumnProperty.ColumnComparator(self)
         # sanity check
         for col in columns:
-            if not hasattr(col, 'name'):
-                if hasattr(col, 'label'):
-                    raise ArgumentError('ColumnProperties must be named for the mapper to work with them.  Try .label() to fix this')
-                raise ArgumentError('%r is not a valid candidate for ColumnProperty' % col)
+            if not isinstance(col, ColumnElement):
+                raise ArgumentError('column_property() must be given a ColumnElement as its argument.  Try .label() or .as_scalar() for Selectables to fix this.')
         
     def create_strategy(self):
         if self.deferred:
diff --git a/lib/sqlalchemy/sql/compiler.py b/lib/sqlalchemy/sql/compiler.py
index 9b24dd5213..d94d3fef67 100644
--- a/lib/sqlalchemy/sql/compiler.py
+++ b/lib/sqlalchemy/sql/compiler.py
@@ -438,7 +438,7 @@ class DefaultCompiler(engine.Compiled):
         if isinstance(column, sql._Label):
             return column
             
-        if select.use_labels and column._label:
+        if select.use_labels and getattr(column, '_label', None):
             return column.label(column._label)
                 
         if \
diff --git a/test/orm/query.py b/test/orm/query.py
index 562b1eee22..ef9e3540d5 100644
--- a/test/orm/query.py
+++ b/test/orm/query.py
@@ -948,18 +948,18 @@ class ExternalColumnsTest(QueryTest):
         clear_mappers()
         try:
             mapper(User, users, properties={
-                'concat': column_property(users.c.id * 2),
+                'count': column_property(select([func.count(addresses.c.id)], users.c.id==addresses.c.user_id).correlate(users))
             })
         except exceptions.ArgumentError, e:
-            assert str(e) == 'ColumnProperties must be named for the mapper to work with them.  Try .label() to fix this'
+            assert str(e) == 'column_property() must be given a ColumnElement as its argument.  Try .label() or .as_scalar() for Selectables to fix this.'
         else:
             raise 'expected ArgumentError'
 
     def test_external_columns_good(self):
         """test querying mappings that reference external columns or selectables."""
         mapper(User, users, properties={
-            'concat': column_property((users.c.id * 2).label('concat')),
-            'count': column_property(select([func.count(addresses.c.id)], users.c.id==addresses.c.user_id).correlate(users).label('count'))
+            'concat': column_property((users.c.id * 2)),
+            'count': column_property(select([func.count(addresses.c.id)], users.c.id==addresses.c.user_id).correlate(users).as_scalar())
         })
 
         mapper(Address, addresses, properties={