def left_join(current_database_name,infos,left_table_name,right_table_name,condition):
global data
left_table = data.joinpath(current_database_name,left_table_name+".csv")
right_table = data.joinpath(current_database_name,right_table_name+".csv")
if (not left_table.exists()) or (not right_table.exists()):
print("Error : Unknown table")
return
left_reader = csv.DictReader(left_table.open("r",newline=""),delimiter="|")
right_reader = csv.DictReader(right_table.open("r",newline=""),delimiter="|")
is_single_condition = re.compile(r"([\w\s\.]+)=([\w\s\.]+)",re.IGNORECASE).match(condition)
if not is_single_condition:
print("ERROR!")
return
left = is_single_condition.group(1).strip()
right = is_single_condition.group(2).strip()
try:
tableA,parmA = left.split(".")
tableB,parmB = right.split(".")
if tableA == left_table_name:
parm_left = parmA
parm_right = parmB
else:
parm_left = parmB
parm_right = parmA
# infos
left_info = []
right_info = []
infos = infos.split(",")
for info in infos:
table,parm = info.split(".")
if table == left_table_name:
left_info.append(parm)
else:
right_info.append(parm)
left_info = ",".join(left_info)
right_info = ",".join(right_info)
except:
left_info = "*"
right_info = "*"
l = []
for i in left_reader:
l.append(i)
r = []
for j in right_reader:
r.append(j)
for left_row in l:
print_infos(left_info,left_row)
for right_row in r:
if left_row[parm_left] == right_row[parm_right]:
print_infos(right_info,right_row)
print("OPERATOR SUCCESS")
def select_from_group_by_having(current_database_name, infos, table_name,
parms, condition):
global data
table = data.joinpath(current_database_name, table_name + ".csv")
if not table.exists():
print("ERROR : Unknown table '%s.%s'" %
(current_database_name, table_name))
return
parms = parms.split(",")
# 所有不同的种类
cate = []
with open(table, "r", newline="") as csvfile:
reader = csv.DictReader(csvfile, delimiter="|")
for item in reader:
tup = tuple(item[parm] for parm in parms)
if tup not in cate:
cate.append(tup)
# 对每一类，用一个列表装起来
l = [[] for i in range(len(cate))]
with open(table, "r", newline="") as csvfile:
reader = csv.DictReader(csvfile, delimiter="|")
for item in reader:
for i in range(len(cate)):
if tuple(item[parm] for parm in parms) == cate[i]:
l[i].append(item)
for i in l:
if check_item_condition(i[0], condition):
print_infos(infos, i[0])
print("OPERATOR SUCCESS")
def select_from_limit(current_database_name, infos, table_name, limit):
global data
table = data.joinpath(current_database_name, table_name + ".csv")
if not table.exists():
print("ERROR : Unknown table '%s.%s'" %
(current_database_name, table_name))
return
if len(limit.split(",")) == 1:
limit_offset = 0
limit_count = int(limit)
else:
limit_offset = int(limit.split(",")[0])
limit_count = int(limit.split(",")[1])
with open(table, "r", newline="") as csvfile:
reader = csv.DictReader(csvfile, delimiter="|")
for i in range(limit_offset):
next(reader)
for i in range(limit_count):
try:
item = next(reader)
print_infos(infos, item)
except:
break
print("OPERATOR SUCCESS")
def select_from_order_by(current_database_name, infos, table_name, order_key):
global data
table = data.joinpath(current_database_name, table_name + ".csv")
if not table.exists():
print("ERROR : Unknown table '%s.%s'" %
(current_database_name, table_name))
return
def order_by_key(item):
return item[order_key]
l = None
with open(table, "r", newline="") as csvfile:
reader = csv.DictReader(csvfile, delimiter="|")
l = sorted(reader, key=order_by_key)
for item in l:
print_infos(infos, item)
print("OPERATOR SUCCESS")
def select_from_where_order_by(current_database_name, infos, table_name,
condition, order_key):
global data
table = data.joinpath(current_database_name, table_name + ".csv")
if not table.exists():
print("ERROR : Unknown table '%s.%s'" %
(current_database_name, table_name))
return
def order_by_key(item):
return item[order_key]
l = []
with open(table, "r", newline="") as csvfile:
reader = csv.DictReader(csvfile, delimiter="|")
for i in reader:
if check_item_condition(i, condition):
l.append(i)
l.sort(key=order_by_key)
for i in l:
print_infos(infos, i)
print("OPERATOR SUCCESS")
def select_from(current_database_name, infos, table_name, condition):
global data
table = data.joinpath(current_database_name, table_name + ".csv")
if not table.exists():
print("ERROR : Unknown table '%s.%s'" %
(current_database_name, table_name))
return
# print(condition)
# and or between and in
# id between 1 and 3
is_between_and = re.compile(r"(\w+) between (\w+) and (\w+)",
re.IGNORECASE).match(condition)
# id = 1
is_single_condition = re.compile(r"([\w\s]+)([=<>]+)([\w\s]+)",
re.IGNORECASE).match(condition)
if is_between_and:
parm = is_between_and.group(1)
begin = int(is_between_and.group(2))
end = int(is_between_and.group(3))
# print(begin)
# print(end)
firstrow = None
with open(table, "r", newline="") as csvfile:
reader = csv.reader(csvfile, delimiter="|")
firstrow = next(reader)
if parm not in firstrow:
print("Error parm!")
return
reader = csv.DictReader(table.open("r", newline=""), delimiter="|")
read_list = []
for i in reader:
read_list.append(i)
for i in read_list:
# print(i)
if int(i[parm]) <= end and int(i[parm]) > begin:
print_infos(infos, i)
if is_single_condition:
left = is_single_condition.group(1).strip()
right = is_single_condition.group(3).strip()
operator = is_single_condition.group(2).strip()
firstrow = None
with open(table, "r", newline="") as csvfile:
reader = csv.reader(csvfile, delimiter="|")
firstrow = next(reader)
if left not in firstrow:
print("Error parm!")
return
reader = csv.DictReader(table.open("r", newline=""), delimiter="|")
for item in reader:
if operator == "=" and item[left] == right:
print_infos(infos, item)
elif operator == ">" and item[left] > right:
print_infos(infos, item)
elif operator == "<" and item[left] < right:
print_infos(infos, item)
elif operator == ">=" and item[left] >= right:
print_infos(infos, item)
elif operator == "<=" and item[left] <= right:
print_infos(infos, item)
else:
pass
print("OPERATOR SUCCESS")