def delete_table_from_db(table_name):
db_data = read_from_json("db_files/db.json")
num_of_files = db_data[table_name]['num of files']
del (db_data[table_name])
db_data['num of tables'] -= 1
write_to_json("db_files/db.json", db_data)
return num_of_files
def create_table(self, table_name: str, fields: List[DBField],
key_field_name: str) -> DBTable:
if os.path.isfile(f"db_files/{table_name}_1.json"):
raise ValueError
if key_field_name not in [field.name for field in fields]:
raise ValueError
db_data = read_from_json("db_files/db.json")
if table_name in db_data.keys():
raise ValueError
write_to_json(f"db_files/{table_name}_1.json", {})
db_data['num of tables'] += 1
db_data[table_name] = \
{'num of files': 1,
'num of lines': 0,
'fields': convert_from_DBfield_to_dict(fields),
'primary key': key_field_name,
'indexes': []
}
write_to_json("db_files/db.json", db_data)
table = DBTable(table_name, fields, key_field_name)
table.create_index(key_field_name)
return table
def insert_record(self, values: Dict[str, Any]) -> None:
db_data = read_from_json("db_files/db.json")
flag = None
primary_key = db_data[self.name]['primary key']
try:
flag = self.get_record(values[primary_key])
except:
db_data = read_from_json("db_files/db.json")
primary_key = get_primary_key(db_data, self.name)
record_to_insert = {
values[primary_key]:
{k: str(v)
for k, v in values.items() if k != primary_key}
}
if end_place_in_file(
db_data,
self.name) and db_data[self.name]['num of lines'] != 0:
db_data[self.name]['num of files'] += 1
write_to_json(
f"db_files/{self.name}_{db_data[self.name]['num of files']}.json",
record_to_insert)
else:
add_to_json(
f"db_files/{self.name}_{db_data[self.name]['num of files']}.json",
record_to_insert)
if flag is not None:
raise ValueError
db_data[self.name]['num of lines'] += 1
write_to_json("db_files/db.json", db_data)
def update_record(self, key: Any, values: Dict[str, Any]) -> None:
db_data = read_from_json("db_files/db.json")
num_of_files = db_data[self.name]['num of files']
for file_num in range(num_of_files):
file_data = read_from_json(
f"db_files/{self.name}_{file_num + 1}.json")
for k in file_data.keys():
if k == str(key):
for field in values.keys():
file_data[k][field] = values[field]
write_to_json(f"db_files/{self.name}_{file_num + 1}.json",
file_data)
return
raise ValueError
def delete_record(self, key: Any) -> None:
db_data = read_from_json("db_files/db.json")
num_of_files = db_data[self.name]['num of files']
flag = False
for file_num in range(num_of_files):
file_data = read_from_json(
f"db_files/{self.name}_{file_num + 1}.json")
for k in file_data.keys():
if k == str(key):
flag = True
del_key = k
break
if flag:
del file_data[del_key]
write_to_json(f"db_files/{self.name}_{file_num + 1}.json",
file_data)
if not flag:
raise ValueError
db_data[self.name]['num of lines'] -= 1
write_to_json("db_files/db.json", db_data)
def update_data(table_name, num, file_data, file_num):
db_data = read_from_json("db_files/db.json")
db_data[table_name]['num of lines'] -= num
write_to_json(f"db_files/{table_name}_{file_num + 1}.json", file_data)
write_to_json("db_files/db.json", db_data)
def __init__(self):
if not os.path.isfile("db_files/db.json"):
write_to_json("db_files/db.json", {'num of tables': 0})