Please tell me how to store char in a field so i can relate it to other field in other model but same module

My py :

from osv import fields, osv
import time

class notebook_project(osv.osv):
    _name = "notebook.project"
    _description = "Notebook Project ID"
    _columns = {
        'project_name' : fields.many2one('project.project', 'Project Name'),
        'project_name_id' : fields.char('Project ID', size=32, required=True, store=True),
        }


notebook_project()

class notebook_member(osv.osv):
    _name = "notebook.member"
    _description = "Notebook Member of Project"
    _columns = {
        'project_member' : fields.many2one('hr.employee', 'Member Name',required=True, store=True),
        'project_id' : fields.related('project_name_id', 'project_id', type='many2one', relation='notebook.project', string='Project ID', store=True, readonly=True',),
        }


notebook_member()

I need the value of project ID ( char ) to be stored so I can call it on other model ( in notebook.member , from notebook.project ) . Thanks in advance :)