Python: dbcur.execute 属性错误：'NoneType' 对象没有 'execute' 属性

Question

我正在尝试运行这段代码：

def getServerSetting(self, setting):
    self.dbcur.execute('select value from settings where setting = ?', [str(setting)])
    rrf = self.dbr.fetchone()
    if rrf is None:
        return False
    else:
        return rrf[0]

但是，当我运行这个Python脚本时，出现了这个错误：

dbcur.execute('select value from settings where setting = ?', [str(setting)])
AttributeError: 'NoneType' object has no attribute 'execute'

Answer 1

试着像这样写你的函数。如果还有错误，告诉我。

def getServerSetting(self, setting):

    if not self.dbcon:
        self.dbcon = MySQLdb.connect(host='localhost', user='removed', passwd='removed', db='removed', port=21)
    self.dbcur = self.dbcon.cursor()

    self.dbcur.execute('select value from settings where setting = ?', [str(setting)])
    rrf = self.dbr.fetchone()
    if rrf is None:
            return False
    else:
            return rrf[0]