def insert_record(table_name, attributes):
RecordManager.set_file_dir('schema/tables/' + table_name + '/')
metadata = load_metadata()
position = RecordManager.insert(table_name,
metadata.tables[table_name].fmt,
tuple(attributes))
for index_name, index in metadata.tables[table_name].indexes.items():
file_path = RecordManager.file_dir + index_name + '.index'
fmt = ''.join(metadata.tables[table_name].columns[column].fmt
for column in index.columns)
manager = IndexManager(file_path, fmt)
key_pos = list(metadata.tables[table_name].columns.keys()).index(
index.columns[0])
key_list = list()
key_list.append(attributes[key_pos])
try:
manager.insert(
key_list, position) # index can be set on single attribute
manager.dump_header()
except ValueError: # duplicated key, the inserted record should be deleted
RecordManager.delete(table_name,
metadata.tables[table_name].fmt,
with_index=True,
record_offset=position)
raise
def delete_record_conditionally(table_name, conditions):
RecordManager.set_file_dir('schema/tables/' + table_name + '/')
metadata = load_metadata()
if len(conditions) == 1:
MinisqlFacade._delete_single_condition(table_name, conditions[0])
elif len(conditions) == 3:
if conditions[1] == 'and':
records = MinisqlFacade.select_record_conditionally(
table_name, conditions)
for record in records:
for index_name, index in metadata.tables[
table_name].indexes.items():
file_path = RecordManager.file_dir + index_name + '.index'
fmt = ''.join(
metadata.tables[table_name].columns[column].fmt
for column in index.columns)
manager = IndexManager(file_path, fmt)
pos = list(
metadata.tables[table_name].columns.keys()).index(
index.columns[0])
key_list = list()
key_list.append(record[pos])
itr = manager.find(key_list)
trash, value = next(itr)
manager.delete(key_list)
manager.dump_header()
RecordManager.delete(table_name,
metadata.tables[table_name].fmt,
with_index=1,
record_offset=value)
# each tuple has its PRIMARY KEY index
# actually only support single attribute index
elif conditions[1] == 'or':
MinisqlFacade._delete_single_condition(table_name,
conditions[0])
MinisqlFacade._delete_single_condition(table_name,
conditions[2])
else:
pass
# link the records outside
else:
pass
def test_persistence(self):
manager = IndexManager('spam', '<id')
manager.insert([42, 7.6], 518)
manager.insert([233, 66.6], 7)
manager.delete([42, 7.6])
manager.dump_header()
manager._manager.flush_all()
del manager
manager = IndexManager('spam', '<id')
self.assertEqual(manager.root, 1)
self.assertEqual(manager.first_deleted_block, 0)
self.assertEqual(manager.total_blocks, 2)
block = BufferManager().get_file_block('spam', 1)
Node = manager.Node
node = Node.frombytes(block.read())
self.assertEqual(node.is_leaf, True)
self.assertEqual(node.keys, [(233, 66.6)])
self.assertEqual(node.children, [7, 0])
def create_index(table_name, index_name, column_name):
RecordManager.set_file_dir('schema/tables/' + table_name + '/')
offset = -1
metadata = load_metadata()
metadata.add_index(table_name, index_name, column_name)
records = RecordManager.select(table_name,
metadata.tables[table_name].fmt,
with_index=False,
conditions={})
file_path = RecordManager.file_dir + index_name + '.index'
table_target = metadata.tables[table_name]
fmt = ''.join(table_target.columns[column].fmt
for column in table_target.indexes[index_name].columns)
manager = IndexManager(file_path, fmt)
key_pos = list(
metadata.tables[table_name].columns.keys()).index(column_name)
for record in records:
key_list = list()
key_list.append(record[key_pos])
offset += 1
manager.insert(key_list, offset)
metadata.dump()
manager.dump_header()
def _delete_single_condition(table_name, condition):
metadata = load_metadata()
index_name = MinisqlFacade._has_index(condition[0], table_name)
if index_name:
print('delete with index on ', condition[0])
attribute_name = condition[0]
operator = condition[1]
key_list = list()
key_list.append(condition[2])
file_path = RecordManager.file_dir + index_name + '.index' #
fmt = metadata.tables[table_name].columns[attribute_name].fmt
manager = IndexManager(file_path, fmt)
if operator == '=':
try:
itr = manager.find(key_list)
it_key, value = next(itr)
record = RecordManager.select(
table_name,
metadata.tables[table_name].fmt,
with_index=True,
record_offset=value)
if it_key[0] == key_list[0]:
MinisqlFacade._delete_stupid_index(record, table_name)
RecordManager.delete(table_name,
metadata.tables[table_name].fmt,
with_index=True,
record_offset=value)
except StopIteration:
pass
elif operator == '>':
for i in manager.find(key_list):
if i[0][0] > key_list[0]:
value = i[1]
record = RecordManager.select(
table_name,
metadata.tables[table_name].fmt,
with_index=True,
record_offset=value)
MinisqlFacade._delete_stupid_index(record, table_name)
RecordManager.delete(table_name,
metadata.tables[table_name].fmt,
with_index=True,
record_offset=value)
elif operator == '<':
for i in manager.iter_leaves():
if i[0][0] < key_list[0]:
value = i[1]
record = RecordManager.select(
table_name,
metadata.tables[table_name].fmt,
with_index=True,
record_offset=value)
MinisqlFacade._delete_stupid_index(record, table_name)
RecordManager.delete(table_name,
metadata.tables[table_name].fmt,
with_index=True,
record_offset=value)
else:
break
manager.dump_header()
else:
MinisqlFacade.delete_record_conditionally_without_index(
table_name, condition)