def import_students(upload):
"""
Importer Statistics from file.
Additionally imports all new object, which will be found.
:param upload:
:return:
"""
success = False
try:
# check format
header = upload.file.readline().decode()
assert header.startswith(HEADER)
except:
header = None
if header:
session = create_session()
subject_ids = []
# collect existing objects and map it
for subject in header.replace(HEADER, '').split(','):
obj, new = get_or_create_by_required(Subject, name=subject)
subject_ids.append(obj.id)
statistics = {(x.student_id, x.room_id, x.quarter_id, x.subject_id): x
for x in session.query(Statistic).filter(
Statistic.subject_id.in_(subject_ids)).all()}
students = {(x.name, x.birth): x.id
for x in session.query(Student).all()}
quarters = {(x.year, x.quarter): x.id
for x in session.query(Quarter).all()}
rooms = {x.name: x.id for x in session.query(Room).all()}
# look at new row from the file
nextline = upload.file.readline()
while nextline:
fields = nextline.decode().replace('\n', '').split(',')
_id, name, birth, room, year, quarter = fields[:6]
birth = datetime.datetime.strptime(birth, "%d/%m/%Y").date()
year = int(year)
stats = fields[6:]
if room in rooms:
room_id = rooms[room]
else:
obj = Room(name=room)
session.add(obj)
session.flush()
room_id = obj.id
rooms[room] = room_id
student_key = (name, birth)
if student_key in students:
student_id = students[student_key]
else:
obj = Student(name=name, birth=birth)
session.add(obj)
session.flush()
student_id = obj.id
students[student_key] = student_id
quarter_key = (year, quarter)
if quarter_key in quarters:
quarter_id = quarters[quarter_key]
else:
obj = Quarter(year=year, quarter=quarter)
session.add(obj)
session.flush()
quarter_id = obj.id
quarters[quarter_key] = quarter_id
# look at every subject column
for subject_id, value in itertools.zip_longest(subject_ids, stats):
value = int(value)
statistic_key = (student_id, room_id, quarter_id, subject_id)
if statistic_key in statistics:
obj = statistics[statistic_key]
if obj.value != value:
obj.value = value
session.flush()
else:
obj = Statistic(student_id=student_id,
room_id=room_id,
quarter_id=quarter_id,
subject_id=subject_id,
value=value)
session.add(obj)
session.flush()
# commit new row objects
session.commit()
nextline = upload.file.readline()
success = True
return success
