fixed error that caused an infinite loop

git-svn-id: http://galileo.dmi.unict.it/svn/relational/trunk@166 014f5005-505e-4b48-8d0a-63407b615a7c

relational/optimizations.py

@@ -258,8 +258,6 @@ def selection_and_product(n,rels):
     changes=0
     
     if n.name=='σ' and n.child.name=='*':
-        changes=1
-        
         l_attr=n.child.left.result_format(rels)
         r_attr=n.child.right.result_format(rels)
         
@@ -282,9 +280,6 @@ def selection_and_product(n,rels):
         right=[]
         both=[]
         
-        print "Attributi R",r_attr, "Attributi L",l_attr
-        print "Gruppi",groups
-        
         for i in groups:
             l_fields=False #has fields in left?
             r_fields=False #has fields in left?
@@ -304,10 +299,9 @@ def selection_and_product(n,rels):
             else:#Unknown.. adding in both
                 both.append(i)
         
-        print "left", left, "right",right,"both",both
-        
         #Preparing left selection
         if len(left)>0:
+            changes=1
             l_node=optimizer.node()
             l_node.name='σ'
             l_node.kind=optimizer.UNARY
@@ -323,6 +317,7 @@ def selection_and_product(n,rels):
         
         #Preparing right selection
         if len(right)>0:
+            changes=1
             r_node=optimizer.node()
             r_node.name='σ'
             r_node.prop=''

relational/optimizer.py

@@ -220,6 +220,33 @@ def tree(expression):
     the root node using the Node class defined in this module.'''
     return node(tokenize(expression))
 
+def optimize_all(expression,rels):
+    '''This function performs all the available optimizations'''
+    n=tree(expression) #Gets the tree
+    total=1
+    while total!=0:
+        total=0
+        for i in optimizations.specific_optimizations:
+            total+=i(n,rels) #Performs the optimization
+            print n
+        for i in optimizations.general_optimizations:
+            total+=i(n) #Performs the optimization
+            print n
+    return n.__str__()
+            
+
+def specific_optimize(expression,rels):
+    '''This function performs specific optimizations. Means that it will need to
+    know the fields used by the relations'''
+    n=tree(expression) #Gets the tree
+    total=1
+    while total!=0:
+        total=0
+        for i in optimizations.specific_optimizations:
+            total+=i(n,rels) #Performs the optimization
+    return n.__str__()
+            
+
 def general_optimize(expression):
     '''This function performs general optimizations. Means that it will not need to
     know the fields used by the relations'''
@@ -251,11 +278,13 @@ if __name__=="__main__":
     rels["S1"]= relation.relation("/home/salvo/dev/relational/trunk/samples/skillo.csv")
     print rels
     #n=tree("π indice,qq,name (ρ age➡qq,id➡indice (P1-P2))")
-    n=tree("σ id==3 and id==indice and indice==2 and name==5 or name<2(P1 * S1)")
-    print optimizations.selection_and_product(n,rels)
+    #n=tree("σ id==3 and indice==2 and name==5 or name<2(P1 * S1)")
+    #print optimizations.selection_and_product(n,rels)
     
-    print n
-    print n.result_format(rels)
+    print specific_optimize("σ id==3 and indice==2 and name==5 or name<2(P1 * S1)",rels)
+    
+    #print n
+    #print n.result_format(rels)
     
     #a=general_optimize("σ age==3 and qq<=2 or nome!='ciccio d\\'urso'(ρ ciccio➡age,nome➡nom(R-Q))")
     #a=general_optimize("σ i==2 (σ b>5 (d))")