def __update_index(self, by_attr, key, value):
current_dir = os.path.dirname(os.path.abspath(__file__))
index_file_path = os.path.join(current_dir, 'indexes', '%s_%s.txt' % (self.table_name, by_attr))
with open(index_file_path, 'r+b') as index_file:
btree = SBplusTree(index_file)
btree.open()
btree[key] = value
def __update_index(self, by_attr, key, value):
current_dir = os.path.dirname(os.path.abspath(__file__))
index_file_path = os.path.join(
current_dir, 'indexes', '%s_%s.txt' % (self.table_name, by_attr))
with open(index_file_path, 'r+b') as index_file:
btree = SBplusTree(index_file)
btree.open()
btree[key] = value
def index(table_name, by_attr):
current_dir = os.path.dirname(os.path.abspath(__file__))
table_file_path = os.path.join(current_dir, 'tables',
'%s.txt' % table_name)
index_file_path = os.path.join(current_dir, 'indexes',
'%s_%s.txt' % (table_name, by_attr))
if not os.path.isfile(table_file_path):
raise FileNotFoundError('No such table')
with open(index_file_path, 'w+b') as index_file:
btree = SBplusTree(index_file, 0, 20, 42)
btree.startup()
with open(table_file_path, 'rb') as table:
# read metadata size
table.seek(-Metadata.header_length, os.SEEK_END)
meta_length = int(table.read(Metadata.header_length))
# read all metadata
table.seek(-(meta_length + Metadata.header_length),
os.SEEK_END)
meta = table.read().split()
table_schema = to_string_list(meta[0].split(Delimiters.attr))
attr_index = table_schema.index(by_attr)
indicies = []
for index in meta[3:-1]:
index_obj = index.split(Delimiters.offset)
indicies.append(
Metadata.Index(offset=int(index_obj[0]),
limit=int(index_obj[1]),
attr_limits=to_int_list(
index_obj[2].split(
Delimiters.attr))))
for index in indicies:
table.seek(index.offset)
for i, limit in enumerate(index.attr_limits):
if i < attr_index:
table.seek(limit, os.SEEK_CUR)
else:
attr = table.read(limit)
btree[attr.decode(DBMS_ENCODING)] = index.as_dict()
break
def index(table_name, by_attr):
current_dir = os.path.dirname(os.path.abspath(__file__))
table_file_path = os.path.join(current_dir, 'tables', '%s.txt' % table_name)
index_file_path = os.path.join(current_dir, 'indexes', '%s_%s.txt' % (table_name, by_attr))
if not os.path.isfile(table_file_path):
raise FileNotFoundError('No such table')
with open(index_file_path, 'w+b') as index_file:
btree = SBplusTree(index_file, 0, 20, 42)
btree.startup()
with open(table_file_path, 'rb') as table:
# read metadata size
table.seek(-Metadata.header_length, os.SEEK_END)
meta_length = int(table.read(Metadata.header_length))
# read all metadata
table.seek(-(meta_length + Metadata.header_length), os.SEEK_END)
meta = table.read().split()
table_schema = to_string_list(meta[0].split(Delimiters.attr))
attr_index = table_schema.index(by_attr)
indicies = []
for index in meta[3:-1]:
index_obj = index.split(Delimiters.offset)
indicies.append(Metadata.Index(
offset=int(index_obj[0]),
limit=int(index_obj[1]),
attr_limits=to_int_list(index_obj[2].split(Delimiters.attr))
))
for index in indicies:
table.seek(index.offset)
for i, limit in enumerate(index.attr_limits):
if i < attr_index:
table.seek(limit, os.SEEK_CUR)
else:
attr = table.read(limit)
btree[attr.decode(DBMS_ENCODING)] = index.as_dict()
break