Abdelwahed,

You should first understand the important basics/conventions on Odoo/OpenERP.

When you use a many2one field,try doing this:

'project_service_id': fields.many2one('project.service', 'Service')

With whatever object/handle you print, are you sure you are browsing through the righ model and reaching to this field?

If this field has a value, then you must do this:

<YourObject>.project_service_id and <YourObject>.project_service_id.name or '' .

Hope this helps.

SerpentCS

(contact@serpentcs.com)

first, i think that yur definition of a m2o field should be dot notated , not underscore... like:
'project_service': fields.many2one('project.service', string='service')

second... if that fields has no value (or it has Null value) it is interpreted as False. so in your report parser, you should check if the field value exists, and suggest some value for cases where it does not exist...

as noted in Tom's answer... in your report (rml or qweb) in part where you call a m2o field value 
(let's say it is o.project_service ) you should do something like:

if o.project_service != Null or o.project_service Is Not False:
    print o.project_service
else:
    print ''

to put it in short (pythonic form) jou can just write:

o.project_service and o.project_service or ''

(in human readable format it would read like: if there is a o.project_service value, write thta value othervise write '' or any other desired value/blank string...)

hope this will explain why and what you need to do in report:)

Hi,

I think you can ues the same example:

object.project_service and object.project_service.name or ''