Add get_column_key

CHANGES.rst

@@ -4,6 +4,12 @@ Changelog
 Here you can see the full list of changes between each SQLAlchemy-Utils release.
 
 
+0.26.5 (2014-07-xx)
+^^^^^^^^^^^^^^^^^^^
+
+- Added get_column_key
+
+
 0.26.4 (2014-06-25)
 ^^^^^^^^^^^^^^^^^^^
 

docs/orm_helpers.rst

@@ -16,6 +16,12 @@ get_bind
 .. autofunction:: get_bind
 
 
+get_column_key
+^^^^^^^^^^^^^^
+
+.. autofunction:: get_column_key
+
+
 get_columns
 ^^^^^^^^^^^
 

setup.py

@@ -44,7 +44,7 @@ for name, requirements in extras_require.items():
 
 setup(
     name='SQLAlchemy-Utils',
-    version='0.26.4',
+    version='0.26.5',
     url='https://github.com/kvesteri/sqlalchemy-utils',
     license='BSD',
     author='Konsta Vesterinen, Ryan Leckey, Janne Vanhala, Vesa Uimonen',

sqlalchemy_utils/__init__.py

@@ -12,6 +12,7 @@ from .functions import (
     drop_database,
     escape_like,
     get_bind,
+    get_column_key,
     get_columns,
     get_declarative_base,
     get_mapper,
@@ -71,7 +72,7 @@ from .types import (
 )
 
 
-__version__ = '0.26.4'
+__version__ = '0.26.5'
 
 
 __all__ = (
@@ -91,6 +92,7 @@ __all__ = (
     generates,
     generic_relationship,
     get_bind,
+    get_column_key,
     get_columns,
     get_declarative_base,
     get_mapper,

sqlalchemy_utils/functions/__init__.py

@@ -20,6 +20,7 @@ from .foreign_keys import (
 )
 from .orm import (
     get_bind,
+    get_column_key,
     get_columns,
     get_declarative_base,
     get_mapper,

sqlalchemy_utils/functions/orm.py

@@ -17,6 +17,33 @@ from sqlalchemy.orm.session import object_session
 from sqlalchemy.orm.util import AliasedInsp
 
 
+def get_column_key(model, column):
+    """
+    Return the key for given column in given model.
+
+    :param model: SQLAlchemy declarative model object
+
+    ::
+
+        class User(Base):
+            __tablename__ = 'user'
+            id = sa.Column(sa.Integer, primary_key=True)
+            name = sa.Column('_name', sa.String)
+
+
+        get_column_key(User, User.__table__.c.name)  # 'name'
+
+    .. versionadded: 0.26.5
+    """
+    for key, c in sa.inspect(model).columns.items():
+        if c is column:
+            return key
+    raise ValueError(
+        "Class %s doesn't have a column 'column.key'",
+        model.__name__
+    )
+
+
 def get_mapper(mixed):
     """
     Return related SQLAlchemy Mapper for given SQLAlchemy object.

tests/functions/test_get_column_key.py

@@ -0,0 +1,34 @@
+from pytest import raises
+
+import sqlalchemy as sa
+from sqlalchemy.ext.declarative import declarative_base
+
+from sqlalchemy_utils import get_column_key
+
+
+class TestGetColumnKey(object):
+    def setup_method(self, method):
+        Base = declarative_base()
+
+        class Building(Base):
+            __tablename__ = 'building'
+            id = sa.Column(sa.Integer, primary_key=True)
+            name = sa.Column('_name', sa.Unicode(255))
+
+        self.Building = Building
+
+    def test_supports_aliases(self):
+        assert (
+            get_column_key(self.Building, self.Building.__table__.c.id)
+            ==
+            'id'
+        )
+        assert (
+            get_column_key(self.Building, self.Building.__table__.c._name)
+            ==
+            'name'
+        )
+
+    def test_throws_value_error_for_unknown_column(self):
+        with raises(ValueError):
+            get_column_key(self.Building, 'unknown')