我正在尝试创建一个将数据存储在本地缓冲区中的类,以及充当数据库的接口。我有以下代码:
class Table(object):
def __init__(self, tableName, **columnDict):
self.tableName = tableName
self.columns = {}
self.types = {}
self.columns['id'] = []
self.types['id'] = 'INT PRIMARY KEY NOT NULL'
for name in columnDict:
self.columns[name] = []
self.types[name] = columnDict[name]
def updateBufferRow(self, index, updateDict):
for key in updateDict:
self.columns[key][index] = updateDict[key]
def getBufferRow(self, index):
row = {}
for key in self.columns:
row[key] = self.columns[key][index]
return row
def __getitem__(self, key, **args):
""" Allows using self[key] method """
return self.getBufferRow(key)
def __setitem__(self, key, value, **args):
""" Allows using self[key] = value method """
self.updateBufferRow(key, value)
以下是我初始化表的方法:
testTable = Table('BestTable', test = 'TestType', test2='INT')
如果我尝试的话,它就像预期的那样工作:
testTable[0]['test'] = "LALALA"
它没有做任何事情,另一方面这更新而不是覆盖表:
testTable[0] = {"test": "LALALA"}
我知道我必须重写updateBufferRow()和getBufferRow()方法,我唯一不确定的是如何使用__getitem__和__setitem__方法获取多个键 任何帮助/提示将不胜感激。谢谢你们!
答案 0 :(得分:3)
dict
返回的__getitem__
与您的列无关。您需要返回可能看起来像dict
的内容,但将__setattr__
次调用回到您的表格列:
class Row(dict):
def __init__(self, table, index, *args, **kw):
self._table, self._index = table, index
super(Row, self).__init__(*args, **kw)
def __setitem__(self, key, value):
super(Row, self).__setitem__(key, value)
self._table.columns[key][self._index] = value
然后返回而不是常规dict
:
def getBufferRow(self, index):
row = {}
for key in self.columns:
row[key] = self.columns[key][index]
return Row(self, index, row)