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 select_record_all(table_name):
metadata = load_metadata()
RecordManager.set_file_dir('schema/tables/' + table_name + '/')
records = RecordManager.select(table_name,
metadata.tables[table_name].fmt,
with_index=False,
conditions={})
return records
def _convert_conditions(table_name, condition):
metadata = load_metadata()
key_pos = list(metadata.tables[table_name].columns.keys()).index(
condition[0])
condition_inter = dict()
condition_convert = dict()
condition_inter[condition[1]] = condition[2]
condition_convert[key_pos] = condition_inter
return condition_convert
def select_record_conditionally_without_index(
table_name, condition): # support only equivalent search
metadata = load_metadata()
condition_convert = MinisqlFacade._convert_conditions(
table_name, condition)
records = RecordManager.select(table_name,
metadata.tables[table_name].fmt,
with_index=False,
conditions=condition_convert)
return records
def _select_single_condition(table_name, condition):
metadata = load_metadata()
index_name = MinisqlFacade._has_index(condition[0], table_name)
if index_name:
print('select 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)
records = list()
if operator == '=':
try:
itr = manager.find(key_list)
it_key, value = next(itr)
if it_key[0] == key_list[0]:
records.append(
RecordManager.select(
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]
records.append(
RecordManager.select(
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]
records.append(
RecordManager.select(
table_name,
metadata.tables[table_name].fmt,
with_index=True,
record_offset=value))
else:
break
else:
pass
else:
records = MinisqlFacade.select_record_conditionally_without_index(
table_name, condition)
return records
def drop_table(table_name):
metadata = load_metadata()
buffer_manager = BufferManager()
MinisqlFacade.delete_record_all(table_name)
shutil.rmtree('schema/tables/' + table_name + '/', True)
buffer_manager.detach_from_file('schema/tables/' + table_name + '/' +
table_name + '.table')
for index_name in metadata.tables[table_name].indexes:
buffer_manager.detach_from_file('schema/tables/' + table_name +
'/' + index_name + '.index')
metadata.drop_table(table_name)
metadata.dump()
def _delete_stupid_index(record, table_name):
metadata = load_metadata()
for index_name, index in metadata.tables[table_name].indexes.items():
key_pos = list(metadata.tables[table_name].columns.keys()).index(
index.columns[0])
attribute_name = index.columns[0]
key_list = list()
key_list.append(record[key_pos])
file_path = RecordManager.file_dir + index_name + '.index'
fmt = metadata.tables[table_name].columns[attribute_name].fmt
in_manager = IndexManager(file_path, fmt)
in_manager.delete(key_list)
def delete_record_conditionally_without_index(table_name, condition):
metadata = load_metadata()
condition_convert = MinisqlFacade._convert_conditions(
table_name, condition)
records = RecordManager.select(table_name,
metadata.tables[table_name].fmt,
with_index=False,
conditions=condition_convert)
for record in records:
MinisqlFacade._delete_stupid_index(record, table_name)
RecordManager.delete(table_name,
metadata.tables[table_name].fmt,
with_index=False,
conditions=condition_convert)
def _has_index(attribute_name, table_name):
metadata = load_metadata()
for index_name, index in metadata.tables[table_name].indexes.items():
if attribute_name in index.columns:
file_path = RecordManager.file_dir + index_name + '.index'
fmt = metadata.tables[table_name].columns[attribute_name].fmt
manager = IndexManager(file_path, fmt)
try:
manager.iter_leaves()
return index_name
except RuntimeError:
pass
else:
pass
return None
def drop_index(index_name):
metadata = load_metadata()
for table_name, table in metadata.tables.items():
if index_name in table.indexes:
file_path = 'schema/tables/' + table_name + '/' + index_name + '.index'
fmt = ''.join(metadata.tables[table_name].columns[column].fmt
for column in table.indexes[index_name].columns)
manager = IndexManager(file_path, fmt)
metadata.drop_index(table_name, index_name)
try:
for i in manager.iter_leaves():
key_list = list()
key_list.append(i[0][0])
manager.delete(key_list)
except RuntimeError:
pass
metadata.dump()
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 delete_record_all(table_name):
RecordManager.set_file_dir('schema/tables/' + table_name + '/')
metadata = load_metadata()
RecordManager.delete(table_name,
metadata.tables[table_name].fmt,
with_index=False,
conditions={})
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)
try:
for i in manager.iter_leaves():
key_list = list()
key_list.append(i[0][0])
manager.delete(key_list)
except RuntimeError:
pass
def create_table(table_name, primary_key, columns):
os.makedirs('schema/tables/' + table_name, exist_ok=True)
metadata = load_metadata() # PK can be set on only one attribute
columns_lst = []
for column in columns:
# generate the fmt for this column
if column[1][0] == 'char':
fmt = str(column[1][1]) + 's'
elif column[1][0] == 'int':
fmt = str(column[1][1]) + 'i'
else:
fmt = str(column[1][1]) + 'd'
columns_lst.append(
Column(column[0],
fmt,
primary_key=(column[0] == primary_key),
unique=column[2]))
metadata.add_table(table_name, *columns_lst)
RecordManager.set_file_dir('schema/tables/' + table_name + '/')
RecordManager.init_table(table_name)
metadata.dump()
def _convert_conditions_dual(table_name, *conditions):
metadata = load_metadata()
if conditions[0][0] == conditions[1][0]:
key_pos = list(metadata.tables[table_name].columns.keys()).index(
conditions[0][0])
condition_inter = dict()
condition_convert = dict()
condition_inter[conditions[0][1]] = conditions[0][2]
condition_inter[conditions[1][1]] = conditions[1][2]
condition_convert[key_pos] = condition_inter
return condition_convert
else:
condition_convert = dict()
for condition in conditions:
key_pos = list(
metadata.tables[table_name].columns.keys()).index(
condition[0])
condition_inter = dict()
condition_inter[condition[1]] = condition[2]
condition_convert[key_pos] = condition_inter
return condition_convert
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()
from catalog_manager import load_metadata meta = load_metadata()
def get_columns_name(table_name):
metadata = load_metadata()
columns = list(metadata.tables[table_name].columns.keys())
return columns
