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

More type safety

Browse Source
This commit is contained in:
Salvo 'LtWorf' Tomaselli 2020-06-14 22:47:51 +02:00
parent c5a71be509
commit 9c3e012e71
No known key found for this signature in database
GPG Key ID: B3A7CF0C801886CF
1 changed files with 5 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
relational/optimizations.py
View File

@ -148,6 +148,7 @@ def down_to_unions_subtractions_intersections(n: parser.Node) -> Tuple[parser.No
changes = 0
_o = (UNION, DIFFERENCE, INTERSECTION)
if isinstance(n, parser.Unary) and n.name == SELECTION and n.child.name in _o:
assert isinstance(n.child, parser.Binary)
l = parser.Unary(SELECTION, n.prop, n.child.left)
r = parser.Unary(SELECTION, n.prop, n.child.right)
@ -159,7 +160,7 @@ def duplicated_projection(n: parser.Node) -> Tuple[parser.Node, int]:
'''This function locates thing like π i ( π j (R)) and replaces
them with π i (R)'''
if n.name == PROJECTION and n.child.name == PROJECTION:
if isinstance(n, parser.Unary) and n.name == PROJECTION and isinstance(n.child, parser.Unary) and n.child.name == PROJECTION:
return parser.Unary(
PROJECTION,
n.prop,
@ -170,7 +171,7 @@ def duplicated_projection(n: parser.Node) -> Tuple[parser.Node, int]:
def selection_inside_projection(n: parser.Node) -> Tuple[parser.Node, int]:
'''This function locates things like σ j (π k(R)) and
converts them into π k(σ j (R))'''
if isinstance(n, parser.Unary) and n.name == SELECTION and n.child.name == PROJECTION:
if isinstance(n, parser.Unary) and n.name == SELECTION and isinstance(n.child, parser.Unary) and n.child.name == PROJECTION:
child = parser.Unary(
SELECTION,
n.prop,
@ -305,7 +306,7 @@ def swap_rename_projection(n: parser.Node) -> Tuple[parser.Node, int]:
Will also eliminate fields in the rename that are cut in the projection.
'''
if n.name == PROJECTION and n.child.name == RENAME:
if isinstance(n, parser.Unary) and n.name == PROJECTION and n.child.name == RENAME:
# π index,name(ρ id➡index(R))
renames = n.child.get_rename_prop()
projections = set(n.get_projection_prop())
@ -515,7 +516,7 @@ def useless_projection(n: parser.Node, rels: Dict[str, Relation]) -> Tuple[parse
'''
Removes projections that are over all the fields
'''
if n.name == PROJECTION and \
if isinstance(n, parser.Unary) and n.name == PROJECTION and \
set(n.child.result_format(rels)) == set(i.strip() for i in n.prop.split(',')):
return n.child, 1