title: Does OpenERP convert False value to NULL when affected to integer?
body: <p>Within <code>OpenERP</code>, when you define a new char field in python and set <code>False</code> as default value, the field will be set to <code>NULL</code> in the db, the <code>ORM</code> taking care of the conversion. Does the <code>ORM</code> also convert integer type the same way, or should I be careful that it may convert it to 0 instead of <code>NULL</code>?</p>
  
  <p>Where could I find the on the fly value conversion rules of <code>OSV</code> (<code>OpenERP ORM</code>)?</p>