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fixed error that caused an infinite loop

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git-svn-id: http://galileo.dmi.unict.it/svn/relational/trunk@166 014f5005-505e-4b48-8d0a-63407b615a7c
This commit is contained in:
LtWorf 2009-05-12 13:49:43 +00:00
parent bc60be3ace
commit e5e7dcddd2
2 changed files with 35 additions and 11 deletions
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9
relational/optimizations.py
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@ -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=''

37
relational/optimizer.py
View File

@ -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))")