CCF_100/relational
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

removed debug prints and added comments

Browse Source 
git-svn-id: http://galileo.dmi.unict.it/svn/relational/trunk@158 014f5005-505e-4b48-8d0a-63407b615a7c
This commit is contained in:
LtWorf 2009-05-11 16:51:43 +00:00
parent f273425312
commit e1d02bcd4c
1 changed files with 15 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
relational/optimizations.py
View File

@ -99,9 +99,7 @@ def duplicated_projection(n):
def selection_inside_projection(n):
'''This function locates things like σ j (π k(R)) and
converts them into π k(σ j (R))'''
#TODO Document this in the wiki.
converts them into π k(σ j (R))'''
changes=0
if n.name=='σ' and n.child.name=='π':
@ -125,30 +123,34 @@ def subsequent_renames(n):
changes=0
if n.name=='ρ' and n.child.name==n.name:
#Located two nested renames.
changes=1
print "PROP",n.prop,"==========",n.child.prop
#Joining the attribute into one
n.prop+=','+n.child.prop
n.child=n.child.child
#Creating a dictionary with the attributes
_vars={}
for i in n.prop.split(','):
q=i.split('➡')
_vars[q[0].strip()]=q[1].strip()
n.child=n.child.child
print _vars
#Scans dictionary to locate things like "a->b,b->c" and replace them with "a->c"
for i in list(_vars.keys()):
print i
if _vars[i] in _vars.keys():
#Double rename on attribute
print "i:%s\tvars[i]:%s\t_vars[_vars[i]]: %s\n" % (i,_vars[i],_vars[_vars[i]])
_vars[i] = _vars[_vars[i]]
_vars.pop(i)
_vars[i] = _vars[_vars[i]] #Sets value
_vars.pop(i) #Removes the unused one
#Reset prop var
n.prop=""
print _vars
#Generates new prop var
for i in _vars.items():
n.prop+="%s➡%s," % (i[0],i[1])
n.prop=n.prop[:-1] #Removing ending comma
#recoursive scan
if n.kind==optimizer.UNARY:
changes+=subsequent_renames(n.child)