[Tutor] mod_python & mysqldb problem

[Danny Yoo]

On Thu, 23 Feb 2006, Patty wrote:

> def addpercent(mp, lp):
>     conn = MySQLdb.connect(host = "localhost", user = "root", passwd =
> "",db ="my_db")
>     cursor = conn.cursor()
>     cursor.execute ("""
>                     UPDATE targets
>                     SET mario_percent = %d, lizard_percent = %d
>                     WHERE target_name = 'anyname'
>                     """, (mp, lp))
>     db.commit()
>     cursor.close()
>     db.close()


Hi Patty,

Does this code work outside of the context of mod_python?

There's something slightly suspicious here in the use of the '%d' format
string:  I'm not sure MySQLdb will accept it.  Let me check...

According to the DB API on parameter styles:
    """
        paramstyle

            String constant stating the type of parameter marker
            formatting expected by the interface. Possible values are
            [2]:

                'qmark'         Question mark style,
                                e.g. '...WHERE name=?'
                'numeric'       Numeric, positional style,
                                e.g. '...WHERE name=:1'
                'named'         Named style,
                                e.g. '...WHERE name=:name'
                'format'        ANSI C printf format codes,
                                e.g. '...WHERE name=%s'
                'pyformat'      Python extended format codes,
                                e.g. '...WHERE name=%(name)s'
    """

    (http://www.python.org/peps/pep-0249.html)

So '%s' acts as a placeholder --- a parameter marker --- where MySQLdb
will later substitute parameters into.  So I'm not certain that '%d' will
work properly.


In any case, you should never get a segfault in Python code, so something
strange is happening.  Try seeing if your code works outside of mod_python
first; that'll give us at least a little more assurance that it isn't
MySQLdb that's doing funny things.  You might also want to talk with the
mod_python folks, since they'll probably be able to give you ideas on how
to get better debugging output here.


Good luck to you!