def find_by_syntax(cls, syntax, strict=True):
"""`
Formulates and executes the SQL necessary to retrieve
level data from the database given a complete syntax.
If the syntax refers to levels that do not exist, the function
returns None unless "strict" is set to False in which case
placeholder levels are returned for any not found in the
database.
"""
segments = syntax.split(":")
query = session.query(Level)
ors = []
for i in range(len(segments)-1, -1, -1):
name = segments[i].replace("+", "%")
if name.count("%"):
name_condition = Level.name.like(name)
else:
name_condition = Level.name==segments[i]
if i == len(segments)-1:
query = query.filter(and_(name_condition, Level.depth==i))
if i == len(segments) - 2:
query = query.join('parent', aliased=True).filter(and_(name_condition, Level.depth==i))
if i < len(segments) - 2:
query = query.join('parent', aliased=True, from_joinpoint=True).filter(and_(name_condition, Level.depth==i))
# sys.stderr.write("Query: " + str(query) + "\n")
results = query.all()
return results
def destroy_children(self):
"""
Destroys all child levels of the instance.
"""
if self.depth == pipeline.settings.depth():
# Level is a terminal level and has no children
return
query = session.query(Level)
# subquery = select([Taggable.c.id], query._criterion,
# from_obj= query._from_obj).as_scalar()
# query = query.filter( )
filters = []
subquery = Level.parent_id == self.id
final = subquery
# Somehow this shit works!
# for i in range(self.depth, len(pipeline.settings.hierarchy()) - 1, 1):
# alias = Level._table.alias()
# subquery = Level.parent_id.in_(select([alias.c.parent_id], subquery))
# final = final | subquery
for i in range(self.depth, len(pipeline.settings.hierarchy()) - 1, 1):
alias = Level._table.alias()
subquery = alias.c.parent_id == self.id
for j in range(self.depth, i, 1):
next_alias = Level._table.alias()
subquery = next_alias.c.parent_id.in_(select([alias.c.id], subquery))
alias = next_alias
subquery = Level.parent_id.in_(select([alias.c.id], subquery))
final = final | subquery
# alias = Level._table.alias()
# # alias2 = Level._table.alias()
# subquery = alias.c.parent_id == self.id
# subquery = Level.parent_id.in_(select([alias.c.id], subquery))
# final = final | subquery
# alias2 = Level._table.alias()
# subquery = alias2.c.parent_id == self.id
# subquery = alias.c.parent_id.in_(select([alias2.c.id], subquery))
# subquery = Level.parent_id.in_(select([alias.c.id], subquery))
# final = final | subquery
#
# alias3 = Level._table.alias()
# subquery = alias3.c.parent_id == self.id
# subquery = alias2.c.parent_id.in_(select([alias3.c.id], subquery))
# subquery = alias.c.parent_id.in_(select([alias2.c.id], subquery))
# subquery = Level.parent_id.in_(select([alias.c.id], subquery))
# final = final | subquery
query = query.filter(final)
# sys.stderr.write(str(query) + "\n\n")
level_list = query.all()
# Must be a better way of doing this!
for level in level_list:
session.delete(level)
session.flush()
