python mysql使用executemany()出现TypeError

Question

    def insertData(self,table,param):
        try:
            self.db.set_character_set('utf8')
            q= []
            for x in param:
                cols = ', '.join(x.keys())
                values = '"," '.join(x.values())
                q.append((table, cols, '"'+values+'"'))
            sql = "INSERT INTO %s(%s) VALUES(%s)"
            try:
                result = self.cur.executemany(sql,q)
                insert_id = self.db.insert_id()
                self.db.commit()
            except MySQLdb.Error,e:
                #发生错误时回滚
                self.db.rollback()
        except MySQLdb.Error,e:
            print self.getCurrentTime(),"数据库错误，原因%d: %s" % (e.args[0], e.args[1])

其中q的部分内容为[('houseurl', 'url', u'"/ershoufang/szlh11469938.html"'), ('houseurl', 'url', u'"/ershoufang/szlh11470634.html"')]

执行以上代码后，出现以下问题：

     29                         sql = "INSERT INTO %s(%s) VALUES(%s)"
     30                         try:
---> 31                                 result = self.cur.executemany(sql,q)
     32                                 insert_id = self.db.insert_id()
     33                                 self.db.commit()

/usr/lib/python2.7/dist-packages/MySQLdb/cursors.pyc in executemany(self, query, args)
    274                 self.errorhandler(self, ProgrammingError, msg.args[0])
    275             else:
--> 276                 self.errorhandler(self, TypeError, msg)
    277         except (SystemExit, KeyboardInterrupt):
    278             raise

/usr/lib/python2.7/dist-packages/MySQLdb/connections.pyc in defaulterrorhandler(***failed resolving arguments***)
     34     del connection
     35     if isinstance(errorvalue, BaseException):
---> 36         raise errorvalue
     37     if errorclass is not None:
     38         raise errorclass(errorvalue)

TypeError: not all arguments converted during string formatting

但是我一条条插入使用execute()就没问题。

Answer 1

"INSERT INTO %s(%s) VALUES(%s)"

這種寫法是錯誤的。佔位符 %s 只能出現在值的地方，不能以表名、欄位名稱出現。 .execute* 不會幫你處理這些事。

你可以預先建構好合適的 SQL 模板，再傳給 .execute*。前提是，你的表名、欄位名稱是確定不會有特殊字元的：

fields = ...
data = ...
sql = 'INSERT INTO {}({}) VALUES(%s)'.format(table, fields)
cur.executemany(sql, data)