change CLIENT_FOUND_ROWS flag in django for mysql-python (MySQLdb)?

问题

I have a problem with MySQL 5.5 INSERT ... ON DUPLICATE KEY UPDATE rows effected mismatch cursor.rowcount in a normal Django project

According to doc:

For INSERT ... ON DUPLICATE KEY UPDATE statements, the affected-rows value per row is 1 if the row is inserted as a new row, 2 if an existing row is updated, and 0 if an existing row is set to its current values. If you specify the CLIENT_FOUND_ROWS flag, the affected-rows value is 1 (not 0) if an existing row is set to its current values.

So I tried in out, it seems that in mysql shell, repeating the INSERT ... ON DUPLICATE KEY UPDATE statement will show

Query OK, 0 rows affected (0.00 sec)

In mysql-python (import MySQLdb),

cursor.rowcount will always be 1 regardless of insert/update/nothing updated

I searched everywhere and can not find a way to change the CLIENT_FOUND_ROWS flag in Django. Anyone know how?

回答1:

Okay, I found out how.

In django/db/backends/mysql/base.py there's

kwargs['client_flag'] = CLIENT.FOUND_ROWS
kwargs.update(settings_dict['OPTIONS'])

From the source code we could just change django project settings.py like this

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.',
        'NAME': '',                      
        'USER': '',                      
        'PASSWORD': '',                  
        'HOST': '', 
        'PORT': '',                      
        'OPTIONS': {
            'client_flag': 0
        }
    }
}

来源：https://stackoverflow.com/questions/19062530/change-client-found-rows-flag-in-django-for-mysql-python-mysqldb