Accountability with MySQL

[Bruno B B Magalháes]

I am designing a simple accountability system so all the partners can have
direct access to it by intranet.

I was designing the data model, and came up with this:

CREATE TABLE `moviments` (
  `moviment_id` int(20) NOT NULL auto_increment,
  `moviment_date` date NOT NULL default '0000-00-00',
  `moviment_description` char(200) NOT NULL default '',
  `moviment_assignor` char(80) NOT NULL default '',
  `moviment_drawee` char(80) NOT NULL default '',
  `moviment_amount` int(20) NOT NULL default '0',
  PRIMARY KEY  (`moviment_id`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1

But I am a little bit stuck with this:

Should I use a column to mark if the moviment has been executed?
About income and outcome, should I use a column called moviment_type or
just put a negative value when is an outcome for exampe?

Does anyone ever made something like that, any other idea that could
improve my little system?

Best regards,
Bruno B B Magalhães