Added __eq__ to relation object

git-svn-id: http://galileo.dmi.unict.it/svn/relational/trunk@66 014f5005-505e-4b48-8d0a-63407b615a7c

CHANGELOG

@@ -45,3 +45,6 @@
 - Outer join methods simplified
 - Form to send a survey
 - Makefile to create .deb package
+
+0.8
+- Added __eq__ to relation object, will compare ignoring order.

relation.py

@@ -335,6 +335,27 @@ class relation (object):
                     newt.content.append(item)
         
         return newt
+    def __eq__(self,other):
+        '''Returns true if the relations are the same, ignoring order of items.
+        This operation is rather heavy, since it requires sorting and comparing.'''
+        other=self.rearrange(other) #Rearranges attributes' order so can compare tuples directly
+        if (self.__class__!=other.__class__)or(self.header!=other.header):
+            return False #Both parameters must be a relation
+        
+        #Comparing header
+        if len(self.header.attributes) != len(other.header.attributes):
+            return False #Not the same number of attributes -> not equals
+        for i in self.header.attributes:
+            if i not in other.header.attributes:
+                return False #Non shared attribute
+        
+        #comparing content
+        if len(self.content) != len(other.content):
+            return False #Not the same 
+        for i in self.content:
+            if i not in other.content:
+                return False
+        return True
         
     def __str__(self):
         '''Returns a string representation of the relation, can be printed with