--- ZSQLExtend/ZSQLExtend.py	2007/08/09 15:09:27	1.119
+++ ZSQLExtend/ZSQLExtend.py	2007/11/05 18:45:35	1.120
@@ -474,6 +474,25 @@ class ZSQLExtendFolder(Folder,Persistent
         """
         return urllib.quote(txt)
     
+    
+    def createIdSet(self, resultset, idField=None):
+        """returns a (frozen)set of IDs from a SQL-resultset (using idField) or a list (if idField=None)"""
+        if idField is None:
+            return frozenset(resultset)
+        else:
+            idlist = [r[idField] for r in resultset]
+            return frozenset(idlist)
+        
+    def opIdSet(self, a, b, op):
+        """operate on sets a and b"""
+        if (op == 'intersect'):
+            return a.intersection(b)
+        elif (op == 'union'):
+            return a.union(b)
+        elif (op == 'diff'):
+            return a.difference(b)
+    
+    
     def searchRel(self,relStatement,statement,wherePart,classes):
         """suche relative haufigkeiten (experimental)"""
         ret={}