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Only holds for union 

Does not hold for other operations.
master
Salvo 'LtWorf' Tomaselli 2016-04-09 10:07:44 +07:00
parent 3139031611
commit 002aca3f68
1 changed files with 2 additions and 2 deletions
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4
relational/optimizations.py
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@ -546,14 +546,14 @@ def projection_and_union(n, rels):
if A and B are union compatible if A and B are union compatible
''' '''
changes = 0 changes = 0
if n.name in {UNION, INTERSECTION, DIFFERENCE} and \ if n.name == UNION and \
n.left.name == PROJECTION and \ n.left.name == PROJECTION and \
n.right.name == PROJECTION and \ n.right.name == PROJECTION and \
set(n.left.child.result_format(rels)) == set(n.right.child.result_format(rels)): set(n.left.child.result_format(rels)) == set(n.right.child.result_format(rels)):
newchild = parser.Node() newchild = parser.Node()
newchild.kind = parser.BINARY newchild.kind = parser.BINARY
newchild.name = n.name newchild.name = UNION
newchild.left = n.left.child newchild.left = n.left.child
newchild.right = n.right.child newchild.right = n.right.child