diff --git a/lib/galaxy/tools/data/__init__.py b/lib/galaxy/tools/data/__init__.py
index 11ad2759079..22edb89eba2 100644
--- a/lib/galaxy/tools/data/__init__.py
+++ b/lib/galaxy/tools/data/__init__.py
@@ -335,7 +335,7 @@ class TabularToolDataTable( ToolDataTable ):
         return rval
 
     def get_version_fields( self ):
-        return ( self._loaded_content_version, self.data )
+        return ( self._loaded_content_version, self.get_fields() )
 
     def parse_column_spec( self, config_element ):
         """
@@ -422,7 +422,7 @@ class TabularToolDataTable( ToolDataTable ):
             return default
         rval = default
         # Look for table entry.
-        for fields in self.data:
+        for fields in self.get_fields():
             if fields[ query_col ] == query_val:
                 rval = fields[ return_col ]
                 break
@@ -444,7 +444,7 @@ class TabularToolDataTable( ToolDataTable ):
         is_error = False
         if self.largest_index < len( fields ):
             fields = self._replace_field_separators( fields )
-            if fields not in self.data or allow_duplicates:
+            if fields not in self.get_fields() or allow_duplicates:
                 self.data.append( fields )
             else:
                 log.debug( "Attempted to add fields (%s) to data table '%s', but this entry already exists and allow_duplicates is False.", fields, self.name )