- The :attr:`.Column.key` attribute is now used as the source of

anonymous bound parameter names within expressions, to match the
existing use of this value as the key when rendered in an INSERT
or UPDATE statement.   This allows :attr:`.Column.key` to be used
as a "substitute" string to work around a difficult column name
that doesn't translate well into a bound parameter name.   Note that
the paramstyle is configurable on :func:`.create_engine` in any case,
and most DBAPIs today support a named and positional style.
fixes #3245

4 files changed, 30 insertions, 4 deletions

diff --git a/doc/build/changelog/changelog_10.rst b/doc/build/changelog/changelog_10.rst
index e63e023d9..4e5e1ba1d 100644
--- a/doc/build/changelog/changelog_10.rst
+++ b/doc/build/changelog/changelog_10.rst
@@ -23,6 +23,19 @@
 
     .. change::
         :tags: bug, sql
+        :tickets: 3245
+
+        The :attr:`.Column.key` attribute is now used as the source of
+        anonymous bound parameter names within expressions, to match the
+        existing use of this value as the key when rendered in an INSERT
+        or UPDATE statement.   This allows :attr:`.Column.key` to be used
+        as a "substitute" string to work around a difficult column name
+        that doesn't translate well into a bound parameter name.   Note that
+        the paramstyle is configurable on :func:`.create_engine` in any case,
+        and most DBAPIs today support a named and positional style.
+
+    .. change::
+        :tags: bug, sql
         :pullreq: github:146
 
         Fixed the name of the :paramref:`.PoolEvents.reset.dbapi_connection`
diff --git a/lib/sqlalchemy/sql/elements.py b/lib/sqlalchemy/sql/elements.py
index fa9b66024..734f78632 100644
--- a/lib/sqlalchemy/sql/elements.py
+++ b/lib/sqlalchemy/sql/elements.py
@@ -1092,7 +1092,7 @@ class BindParameter(ColumnElement):
         """
         if isinstance(key, ColumnClause):
             type_ = key.type
-            key = key.name
+            key = key.key
         if required is NO_ARG:
             required = (value is NO_ARG and callable_ is None)
         if value is NO_ARG:
@@ -3335,7 +3335,7 @@ class ColumnClause(Immutable, ColumnElement):
             return name
 
     def _bind_param(self, operator, obj):
-        return BindParameter(self.name, obj,
+        return BindParameter(self.key, obj,
                              _compared_to_operator=operator,
                              _compared_to_type=self.type,
                              unique=True)
diff --git a/test/dialect/mssql/test_reflection.py b/test/dialect/mssql/test_reflection.py
index e93162a8e..0ef69f656 100644
--- a/test/dialect/mssql/test_reflection.py
+++ b/test/dialect/mssql/test_reflection.py
@@ -187,7 +187,7 @@ class InfoCoerceUnicodeTest(fixtures.TestBase, AssertsCompiledSQL):
         stmt = tables.c.table_name == 'somename'
         self.assert_compile(
             stmt,
-            "[TABLES_1].[TABLE_NAME] = :TABLE_NAME_1",
+            "[TABLES_1].[TABLE_NAME] = :table_name_1",
             dialect=dialect
         )
 
@@ -197,7 +197,7 @@ class InfoCoerceUnicodeTest(fixtures.TestBase, AssertsCompiledSQL):
         stmt = tables.c.table_name == 'somename'
         self.assert_compile(
             stmt,
-            "[TABLES_1].[TABLE_NAME] = CAST(:TABLE_NAME_1 AS NVARCHAR(max))",
+            "[TABLES_1].[TABLE_NAME] = CAST(:table_name_1 AS NVARCHAR(max))",
             dialect=dialect
         )
 
diff --git a/test/sql/test_compiler.py b/test/sql/test_compiler.py
index bfafed599..5d1afe616 100644
--- a/test/sql/test_compiler.py
+++ b/test/sql/test_compiler.py
@@ -435,6 +435,19 @@ class SelectTest(fixtures.TestBase, AssertsCompiledSQL):
             dialect=default.DefaultDialect(paramstyle='pyformat')
         )
 
+    def test_anon_param_name_on_keys(self):
+        self.assert_compile(
+            keyed.insert(),
+            "INSERT INTO keyed (x, y, z) VALUES (%(colx)s, %(coly)s, %(z)s)",
+            dialect=default.DefaultDialect(paramstyle='pyformat')
+        )
+        self.assert_compile(
+            keyed.c.coly == 5,
+            "keyed.y = %(coly_1)s",
+            checkparams={'coly_1': 5},
+            dialect=default.DefaultDialect(paramstyle='pyformat')
+        )
+
     def test_dupe_columns(self):
         """test that deduping is performed against clause
         element identity, not rendered result."""