def execute_delete(node):
if not __check_power(node.type, [node.table_name]):
return
if not __check_table([node.table_name]):
print("Error: This table isn't exists.")
return
data_dict = DataDict(node.table_name)
names = data_dict.table_attr_names()
table = TableFile(data_dict, node.table_name)
table_data = table.load_data()
old_len = len(table_data)
print("where_list: ", node.where_list, type(node.where_list))
# for where_item in node.where_list:
# print("where_item", where_item)
try:
table.data_list = []
for line in table_data:
is_true = check_where(node.where_list, names, line)
print("is_true: ", is_true) if VISIBLE is True else None
if not is_true:
table.data_list.append(line)
except Exception as ex:
print("Error: %s." % ex)
return
new_len = len(table.data_list)
table.write_back()
index_dict.load_index() # 表中记录删除后，索引文件也要相应的发生改变
print("%d line(s) are deleted." % (old_len - new_len))
def execute_alert(node):
if not __check_power(node.type, [node.table_name]):
return
if not data_dict.has_table(node.table_name):
print "Error: The table does not exist."
return
names = data_dict.table_attr_names(node.table_name)
table = TableFile(data_dict, node.table_name)
data = table.load_data()
if node.op == "ADD":
if node.attr_list.attr_name in names:
print "Error: The attr's name already exists."
return
data_dict.dict[node.table_name] += [node.attr_list]
for idx in range(len(data)): data[idx].append("NULL")
elif node.op == "DROP":
attr_name = node.attr_list[0]
if attr_name not in names:
print "Error: The attr's name does not exist."
return
old_list = data_dict.dict[node.table_name]
data_dict.dict[node.table_name] = [attr for attr in old_list if attr.attr_name != attr_name]
idx_remove = names.index(attr_name)
for idx in range(len(data)): del data[idx][idx_remove]
index_dict.drop_index(node.table_name, attr_name)
table.data_list = data
table.write_back()
data_dict.write_back()
print "Alert table successful."
def execute_alert(node):
if not __check_power(node.type, [node.table_name]):
return
if not data_dict.has_table(node.table_name):
print "Error: The table does not exist."
return
names = data_dict.table_attr_names(node.table_name)
table = TableFile(data_dict, node.table_name)
data = table.load_data()
if node.op == "ADD":
if node.attr_list.attr_name in names:
print "Error: The attr's name already exists."
return
data_dict.dict[node.table_name] += [node.attr_list]
for idx in range(len(data)):
data[idx].append("NULL")
elif node.op == "DROP":
attr_name = node.attr_list[0]
if attr_name not in names:
print "Error: The attr's name does not exist."
return
old_list = data_dict.dict[node.table_name]
data_dict.dict[node.table_name] = [
attr for attr in old_list if attr.attr_name != attr_name
]
idx_remove = names.index(attr_name)
for idx in range(len(data)):
del data[idx][idx_remove]
index_dict.drop_index(node.table_name, attr_name)
table.data_list = data
table.write_back()
data_dict.write_back()
print "Alert table successful."
def execute_delete(node):
if not __check_power(node.type, [node.table_name]):
return
if not data_dict.has_table(node.table_name):
print("Error: The table does not exist.")
return
names = data_dict.table_attr_names(node.table_name)
table = TableFile(data_dict, node.table_name)
data = table.load_data()
old_len = len(data)
try:
table.data_list = [line for line in data if not check_where(node.where_list, names, line)]
except Exception as e:
print("Error: %s." % e)
# print traceback.format_exc()
return
new_len = len(table.data_list)
table.write_back()
index_dict.load_index()
print("%d line(s) are deleted." % (old_len - new_len))
def execute_alert(node):
if not __check_power(node.type, [node.table_name]):
return
if not __check_table([node.table_name]):
print("Error: This table isn't exists.")
return
data_dict = DataDict(node.table_name)
names = data_dict.table_attr_names()
table = TableFile(data_dict, node.table_name)
table_data = table.load_data()
if node.op == "ADD":
if node.attr_list.attr_name in names:
print("Error: The attr's name already exists.")
return
data_dict.dict[node.table_name] += [node.attr_list]
for line in table_data:
line.append("NULL")
# for idx in range(len(table_data)): table_data[idx].append("NULL")
elif node.op == "DROP":
attr_name = node.attr_list[0]
# for it in node.attr_list:
# print(it, type(it))
if attr_name not in names:
print("Error: The attr's name does not exist.")
return
old_list = data_dict.dict[node.table_name]
data_dict.dict[node.table_name] = [
attr for attr in old_list if attr.attr_name != attr_name
]
index_remove = names.index(attr_name)
for line in table_data:
line.pop(index_remove)
# 当某个属性drop是，如果其有索引，则也要相应的drop
index_dict.drop_index(node.table_name, attr_name)
# print("table.data_list: ")
# for it in table.data_list:
# print(it)
# table.data_list = table_data
table.write_back()
data_dict.write_back()
print("Alert table successful.")
def execute_update(node):
if not __check_power(node.type, [node.table_name]):
return
if not data_dict.has_table(node.table_name):
print("Error: The table does not exist.")
return
names = data_dict.table_attr_names(node.table_name)
table = TableFile(data_dict, node.table_name)
data = table.load_data()
updated_lines = 0
try:
for idx in range(len(data)):
if check_where(node.where_list, names, data[idx]):
updated_lines += 1
set_value(data[idx], names, node.set_list)
except Exception as e:
print("Error: %s." % e)
# print traceback.format_exc()
return
table.write_back()
print("%d line(s) are updated." % updated_lines)
def execute_update(node):
if not __check_power(node.type, [node.table_name]):
return
if not __check_table([node.table_name]):
print("Error: This table isn't exists.")
return
data_dict = DataDict(node.table_name)
names = data_dict.table_attr_names()
table = TableFile(data_dict, node.table_name)
table_data = table.load_data()
update_line = 0
try:
for line in table_data:
# 如果line符合where的条件，则返回True
if check_where(node.where_list, names, line):
set_value(line, names, node.set_list)
print("node.where_list: ", node.where_list)
update_line += 1
except Exception as ex:
print("Error: %s." % ex)
return
table.write_back()
index_dict.load_index() # 表中记录更新后，索引文件也要相应的发生改变
print("%d line(s) are updated." % update_line)