sql_column changed to sql_predicate and now generates full predicate …

…of multiple columns and directions

django_sortable/sortable.py

@@ -70,25 +70,26 @@ def comparer(left, right):
     return result
 
 
-  def sql_column(self, field_name, direction='asc', default=None):
-    """Returns a column for use in a SQL ORDER BY clause."""
+  def sql_predicate(self, field_name, direction='asc', default=None):
+    """Returns a predicate for use in a SQL ORDER BY clause."""
 
     if self.fields:
       try:
-        field = self.fields[field_name]
+        fields = self.fields[field_name]
       except KeyError:
-        return default
+        fields = default
     else:
-      field = field_name
+      fields = field_name
 
     if direction not in ('asc', 'desc'):
-      return default
+      fields = default
 
-    return '%s %s' % (field, direction.upper())
+    fields = Sortable.prepare_fields(fields, direction, sql_predicate=True)
+    return ', '.join(fields)
 
 
   @staticmethod
-  def prepare_fields(fields, direction):
+  def prepare_fields(fields, direction, sql_predicate=False):
     """Given a list or tuple of fields and direction, return a list of fields 
     with their appropriate order_by direction applied.
 
@@ -99,6 +100,8 @@ def prepare_fields(fields, direction):
     ['one', '-two', '-three', '-four', 'five']
     >>> Sortable.prepare_fields(fields, 'not_asc_or_desc')
     ['one', '-two', 'three', 'four', '-five']
+    >>> Sortable.prepare_fields(fields, 'desc', True)
+    ['one ASC', 'two DESC', 'three DESC', 'four DESC', 'five ASC']
     """
 
     if direction not in ('asc', 'desc'):
@@ -115,4 +118,15 @@ def prepare_fields(fields, direction):
       else:
         field = field[1:] if field.startswith('+') else field
         fields[i] = (direction == 'desc' and '-' or '') + field
+
+    if not sql_predicate:
+      return fields
+
+    # determine sql predicates from list
+    fields = list(fields)
+    for i, field in enumerate(fields):
+      if field.startswith('-'):
+        fields[i] = '%s DESC' % (field[1:],)
+      else:
+        fields[i] = '%s ASC' % (field,)
     return fields

readme.md

@@ -111,7 +111,7 @@ __authors.html__
 
 ##Raw SQL Usage
 
-You can use django-sortable with raw SQL queries by asking it for ordering columns. This way you can build the query yourself and append an `ORDER BY` clause. Here's an example:
+You can use django-sortable with raw SQL queries by asking it for ordering columns. This way you can build the query yourself and append a predicate generated by django-sortable in the `ORDER BY` clause. Here's an example:
 
 __views.py__
 
@@ -125,10 +125,10 @@ __views.py__
         direction = request.GET.get('dir', 'asc')
 
         # also, you can pass in a default ordering column(s)
-        order_col = sortable.sql_column(
+        order_col = sortable.sql_predicate(
             field_name=field_name, 
             direction=direction, 
-            default='m.title ASC, p.title ASC, t.condition DESC'
+            default=('m.title', 'p.title', '-t.condition')
         )
 
         sql = '''

setup.py

@@ -16,10 +16,10 @@
                 'Topic :: Software Development :: Libraries :: Python Modules' 
               ]
 
-KEYWORDS = 'sorting sortable queryset pagination django'
+KEYWORDS = 'sorting sortable queryset sql pagination django'
 
 setup(name='django-sortable',
-    version='0.2.1',
+    version='0.3.0',
     description='Flexible sorting for Django applications',
     long_description=LONG_DESCRIPTION,
     author='Drew Yeaton',