db.create_tables causes exception in MySQLdb

After creating model classes, I attempted to run db.create_tables and received the following error:

Traceback (most recent call last):
  File "/Applications/PyCharm.app/Contents/helpers/pydev/pydevd.py", line 1580, in <module>
    globals = debugger.run(setup['file'], None, None, is_module)
  File "/Applications/PyCharm.app/Contents/helpers/pydev/pydevd.py", line 964, in run
    pydev_imports.execfile(file, globals, locals)  # execute the script
  File "/Users/codylandry/PycharmProjects/servicefusion/web2py/applications/servicefusion2/modules/create_db.py", line 197, in <module>
    pw_db.create_tables(tables, safe=True)
  File "/Users/codylandry/PycharmProjects/servicefusion/venv/lib/python2.7/site-packages/peewee.py", line 3772, in create_tables
    create_model_tables(models, fail_silently=safe)
  File "/Users/codylandry/PycharmProjects/servicefusion/venv/lib/python2.7/site-packages/peewee.py", line 5176, in create_model_tables
    m.create_table(**create_table_kwargs)
  File "/Users/codylandry/PycharmProjects/servicefusion/venv/lib/python2.7/site-packages/peewee.py", line 4857, in create_table
    db.create_table(cls)
  File "/Users/codylandry/PycharmProjects/servicefusion/venv/lib/python2.7/site-packages/peewee.py", line 3769, in create_table
    return self.execute_sql(*qc.create_table(model_class, safe))
  File "/Users/codylandry/PycharmProjects/servicefusion/venv/lib/python2.7/site-packages/peewee.py", line 3683, in execute_sql
    cursor.execute(sql, params or ())
  File "/Users/codylandry/PycharmProjects/servicefusion/venv/lib/python2.7/site-packages/MySQLdb/cursors.py", line 187, in execute
    query = query % tuple([db.literal(item) for item in args])
TypeError: not enough arguments for format string

Tracing this to cursors.py I found that the args keyword argument in the execute function is an empty tuple instead of None.

    def execute(self, query, args=None):

        """Execute a query.

        query -- string, query to execute on server
        args -- optional sequence or mapping, parameters to use with query.

        Note: If args is a sequence, then %s must be used as the
        parameter placeholder in the query. If a mapping is used,
        %(key)s must be used as the placeholder.

        Returns long integer rows affected, if any

        """
        del self.messages[:]
        db = self._get_db()
        if isinstance(query, unicode):
            query = query.encode(db.unicode_literal.charset)
        if args is not None:
            if isinstance(args, dict):
                query = query % dict((key, db.literal(item))
                                     for key, item in args.iteritems())
            else:
                query = query % tuple([db.literal(item) for item in args])
        try:
            r = None
            r = self._query(query)
        except TypeError, m:
            if m.args[0] in ("not enough arguments for format string",
                             "not all arguments converted"):
                self.messages.append((ProgrammingError, m.args[0]))
                self.errorhandler(self, ProgrammingError, m.args[0])
            else:
                self.messages.append((TypeError, m))
                self.errorhandler(self, TypeError, m)
        except (SystemExit, KeyboardInterrupt):
            raise
        except:
            exc, value, tb = sys.exc_info()
            del tb
            self.messages.append((exc, value))
            self.errorhandler(self, exc, value)
        self._executed = query
        if not self._defer_warnings: self._warning_check()
        return r

If this is being caused by my model, I’m unclear as to how. I ran the generated sql and was able to create the table the debugger had broke at, so I believe the model is written correctly. I think this just a matter of passing None if there are no arguments to the execute function.

I found this in peewee.py. I’d submit a PR to change it, but I can only test it against mysql.

 def execute_sql(self, sql, params=None, require_commit=True):
        logger.debug((sql, params))
        with self.exception_wrapper:
            cursor = self.get_cursor()
            try:
                cursor.execute(sql, params or ())  # <== should be params or None ?
            except Exception:
                if self.autorollback and self.get_autocommit():
                    self.rollback()
                raise
            else:
                if require_commit and self.get_autocommit():
                    self.commit()
        return cursor

[codylandry]

I verified that double % works. Sorry to waste your time. It wasn’t obvious to me at first why that would fail. Thanks for looking into it though.

[pylipp]

I have an application that must support both Sqlite and MySQL. How can I make the above EnumField compatible with SqliteDatabase? When I use the option field_types={"ENUM": "TEXT"}, the produced DDL is not valid for Sqlite:

customerType TEXT("Customer", "LEAD")

Instead I want customerType TEXT.