- added literal_column() to specify a column clause that should not undergo any quoting

- straight text sent to select() added as literal_column
- fix for issue in [ticket:450]

4 files changed, 16 insertions, 13 deletions

diff --git a/lib/sqlalchemy/ansisql.py b/lib/sqlalchemy/ansisql.py
index 40ea5b00a..63ee5f7fd 100644
--- a/lib/sqlalchemy/ansisql.py
+++ b/lib/sqlalchemy/ansisql.py
@@ -932,9 +932,7 @@ class ANSIIdentifierPreparer(object):
     
     def format_column(self, column, use_table=False):
         """Prepare a quoted column name """
-        # TODO: isinstance alert !  get ColumnClause and Column to better
-        # differentiate themselves
-        if isinstance(column, schema.SchemaItem):
+        if not getattr(column, 'is_literal', False):
             if use_table:
                 return self.format_table(column.table, use_schema=False) + "." + self.__generic_obj_format(column, column.name)
             else:
diff --git a/lib/sqlalchemy/databases/oracle.py b/lib/sqlalchemy/databases/oracle.py
index 8730ecdb1..7221d5662 100644
--- a/lib/sqlalchemy/databases/oracle.py
+++ b/lib/sqlalchemy/databases/oracle.py
@@ -394,7 +394,7 @@ class OracleCompiler(ansisql.ANSICompiler):
                 orderby = self.strings[orderby]
             class SelectVisitor(sql.ClauseVisitor):
                 def visit_select(self, select):
-                    select.append_column(sql.column("ROW_NUMBER() OVER (ORDER BY %s)" % orderby).label("ora_rn"))
+                    select.append_column(sql.literal_column("ROW_NUMBER() OVER (ORDER BY %s)" % orderby).label("ora_rn"))
             select.accept_visitor(SelectVisitor())
             limitselect = sql.select([c for c in select.c if c.key!='ora_rn'])
             if select.offset is not None:
@@ -429,7 +429,7 @@ class OracleCompiler(ansisql.ANSICompiler):
                 orderby = select.oid_column
                 orderby.accept_visitor(self)
                 orderby = self.strings[orderby]
-            select.append_column(sql.column("ROW_NUMBER() OVER (ORDER BY %s)" % orderby).label("ora_rn"))
+            select.append_column(sql.literal_column("ROW_NUMBER() OVER (ORDER BY %s)" % orderby).label("ora_rn"))
             limitselect = sql.select([c for c in select.c if c.key!='ora_rn'])
             if select.offset is not None:
                 limitselect.append_whereclause("ora_rn>%d" % select.offset)
diff --git a/lib/sqlalchemy/schema.py b/lib/sqlalchemy/schema.py
index 44ba85453..ae712252b 100644
--- a/lib/sqlalchemy/schema.py
+++ b/lib/sqlalchemy/schema.py
@@ -193,9 +193,9 @@ class Table(SchemaItem, sql.TableClause):
         quote_schema=False : indicates that the Namespace identifier must be properly escaped and quoted before being sent 
         to the database. This flag overrides all other quoting behavior.
         
-        case_sensitive=True : indicates quoting should be used if the identifier needs it.
+        case_sensitive=True : indicates quoting should be used if the identifier contains mixed case.
         
-        case_sensitive_schema=True : indicates quoting should be used if the identifier needs it.
+        case_sensitive_schema=True : indicates quoting should be used if the identifier contains mixed case.
         """
         super(Table, self).__init__(name)
         self._metadata = metadata
@@ -362,7 +362,7 @@ class Column(SchemaItem, sql._ColumnClause):
         to the database.  This flag should normally not be required as dialects can auto-detect conditions where quoting
         is required.
 
-        case_sensitive=True : indicates quoting should be used if the identifier needs it.
+        case_sensitive=True : indicates quoting should be used if the identifier contains mixed case.
         """
         name = str(name) # in case of incoming unicode        
         super(Column, self).__init__(name, None, type)
diff --git a/lib/sqlalchemy/sql.py b/lib/sqlalchemy/sql.py
index a59b91b4c..259ef00b6 100644
--- a/lib/sqlalchemy/sql.py
+++ b/lib/sqlalchemy/sql.py
@@ -10,7 +10,7 @@ from sqlalchemy import types as sqltypes
 import string, re, random, sets
 
 
-__all__ = ['text', 'table', 'column', 'func', 'select', 'update', 'insert', 'delete', 'join', 'and_', 'or_', 'not_', 'between_', 'case', 'cast', 'union', 'union_all', 'except_', 'except_all', 'intersect', 'intersect_all', 'null', 'desc', 'asc', 'outerjoin', 'alias', 'subquery', 'literal', 'bindparam', 'exists', 'extract','AbstractDialect', 'ClauseParameters', 'ClauseVisitor', 'Executor', 'Compiled', 'ClauseElement', 'ColumnElement', 'ColumnCollection', 'FromClause', 'TableClause', 'Select', 'Alias', 'CompoundSelect','Join', 'Selectable']
+__all__ = ['text', 'table', 'column', 'literal_column', 'func', 'select', 'update', 'insert', 'delete', 'join', 'and_', 'or_', 'not_', 'between_', 'case', 'cast', 'union', 'union_all', 'except_', 'except_all', 'intersect', 'intersect_all', 'null', 'desc', 'asc', 'outerjoin', 'alias', 'subquery', 'literal', 'bindparam', 'exists', 'extract','AbstractDialect', 'ClauseParameters', 'ClauseVisitor', 'Executor', 'Compiled', 'ClauseElement', 'ColumnElement', 'ColumnCollection', 'FromClause', 'TableClause', 'Select', 'Alias', 'CompoundSelect','Join', 'Selectable']
 
 def desc(column):
     """return a descending ORDER BY clause element, e.g.:
@@ -220,10 +220,14 @@ def label(name, obj):
     return _Label(name, obj)
     
 def column(text, table=None, type=None, **kwargs):
-    """returns a textual column clause, relative to a table.  this is also the primitive version of
+    """return a textual column clause, relative to a table.  this is also the primitive version of
     a schema.Column which is a subclass. """
     return _ColumnClause(text, table, type, **kwargs)
 
+def literal_column(text, table=None, type=None, **kwargs):
+    """return a textual column clause with the 'literal' flag set.  this column will not be quoted"""
+    return _ColumnClause(text, table, type, is_literal=True, **kwargs)
+    
 def table(name, *columns):
     """returns a table clause.  this is a primitive version of the schema.Table object, which is a subclass
     of this object."""
@@ -1251,13 +1255,14 @@ legal_characters = util.Set(string.ascii_letters + string.digits + '_')
 class _ColumnClause(ColumnElement):
     """represents a textual column clause in a SQL statement.  May or may not
     be bound to an underlying Selectable."""
-    def __init__(self, text, selectable=None, type=None, _is_oid=False, case_sensitive=True):
+    def __init__(self, text, selectable=None, type=None, _is_oid=False, case_sensitive=True, is_literal=False):
         self.key = self.name = text
         self.table = selectable
         self.type = sqltypes.to_instance(type)
         self._is_oid = _is_oid
         self.__label = None
-        self.case_sensitive = False #text.isalpha() and not text.islower()
+        self.case_sensitive = case_sensitive
+        self.is_literal = is_literal
     def _get_label(self):
         if self.__label is None:
             if self.table is not None and self.table.named_with_column():
@@ -1524,7 +1529,7 @@ class Select(_SelectBaseMixin, FromClause):
                 
     def append_column(self, column):
         if _is_literal(column):
-            column = _ColumnClause(str(column), self)
+            column = literal_column(str(column), table=self)
 
         self._raw_columns.append(column)