Python 操作数据库

下面这段代码和使用 ORM 操作有啥区别？

class DbCommonLibaray(object):

def executeQuery(self, sql):
    cursor = connection.cursor()  # 获得一个游标(cursor)对象
    cursor.execute(sql)
    rawData = cursor.fetchall()
    col_names = [desc[0] for desc in cursor.description]
    result = []
    for row in rawData:
        objDict = {}
        # 把每一行的数据遍历出来放到 Dict 中
        for index, value in enumerate(row):
            objDict[col_names[index]] = value
        result.append(objDict)
    return result

def GetDTByPage(tableName, conditions, orderby, selectField="*", pageIndex=1, pageSize=20):
    if not selectField:
        selectField = "*"
    if conditions:
        conditions = "WHERE " + conditions
    sqlStart = str((pageIndex - 1) * pageSize)
    sqlEnd = str(pageIndex * pageSize)
    sqlQuery = "SELECT " + str(selectField) + " FROM " + tableName + " " + str(conditions) + " ORDER BY " + str(
        orderby) + " LIMIT " + str(sqlStart) + ", " + str(sqlEnd)
    returnValue = DbCommonLibaray.executeQuery(None, sqlQuery)
    return returnValue