使用MySQL Connector更新数据库详情时遇到'TypeError: 'NoneType' object is not subscriptable'错误求助

这个报错的根源很明确：你在循环遍历SELECT查询结果的过程中，复用了同一个cursor对象去执行UPDATE语句，这会直接清空之前SELECT生成的结果集。当循环尝试获取下一条数据时，cursor内部的_rows已经变成了None，自然就触发了“不能对None做下标操作”的错误——哪怕你设置了buffered=True也没用，因为同一个cursor执行新的SQL语句后，旧的结果集就会被释放。

给你两个简单有效的解决办法：

方法一：提前读取所有查询结果 #

先把SELECT的结果全部取出来存到一个列表里，之后遍历这个列表处理更新，这样cursor的后续操作就不会影响到已经拿到的结果：

def getRepos():
    cursor.execute("select repo_name,github_id from user_repo WHERE Processed = 'N'")
    # 一次性取出所有结果存入列表
    repos_list = cursor.fetchall()
    
    for repo in repos_list:
        username = repo[1]
        repo_name = repo[0]
        total_commit = total_commit_fetch_web_scrap(repo_name, username)
        total_commit_user = total_commit_user_func(repo_name, username)
        total_contributors = total_contributors_func(repo_name, username)
        language_dict = {}
        fetch_language(username, repo_name, language_dict)
        
        sql = 'UPDATE user_repo SET contributors=%s, total_commits=%s, commit_by_user=%s, language_1=%s, language_2=%s, language_3=%s, language_4=%s, language_5=%s, language_6=%s, language_7=%s WHERE repo_name=%s AND github_id=%s;'
        val = (total_contributors, total_commit, total_commit_user, language_dict['languages1'], language_dict['languages2'], language_dict['languages3'], language_dict['languages4'], language_dict['languages5'], language_dict['languages6'], language_dict['languages7'], repo_name, username)
        cursor.execute(sql,val)
        connection.commit()

方法二：使用两个独立的cursor #

创建两个不同的cursor对象，一个专门负责执行SELECT查询和遍历结果，另一个专门处理UPDATE操作，这样两个操作的结果集完全不会互相干扰：

def getRepos():
    # 分别创建查询和更新用的cursor
    select_cursor = connection.cursor(buffered=True)
    update_cursor = connection.cursor()
    
    select_cursor.execute("select repo_name,github_id from user_repo WHERE Processed = 'N'")
    for repo in select_cursor:
        username = repo[1]
        repo_name = repo[0]
        total_commit = total_commit_fetch_web_scrap(repo_name, username)
        total_commit_user = total_commit_user_func(repo_name, username)
        total_contributors = total_contributors_func(repo_name, username)
        language_dict = {}
        fetch_language(username, repo_name, language_dict)
        
        sql = 'UPDATE user_repo SET contributors=%s, total_commits=%s, commit_by_user=%s, language_1=%s, language_2=%s, language_3=%s, language_4=%s, language_5=%s, language_6=%s, language_7=%s WHERE repo_name=%s AND github_id=%s;'
        val = (total_contributors, total_commit, total_commit_user, language_dict['languages1'], language_dict['languages2'], language_dict['languages3'], language_dict['languages4'], language_dict['languages5'], language_dict['languages6'], language_dict['languages7'], repo_name, username)
        update_cursor.execute(sql,val)
        connection.commit()
    
    # 使用完毕后关闭cursor，养成好习惯
    select_cursor.close()
    update_cursor.close()

两种方法都能解决你的问题，选哪个看你个人习惯——方法一更简洁，方法二更清晰，适合复杂场景下区分不同操作的职责。

内容的提问来源于stack exchange，提问作者lex