To merge the fields in one you can use compute on field. for example.

class res_partner(models.Model):
    _inherit = 'res.partner' # extending partner model

    def merge_string(self):
        if self.name
        return self.title or '' + self.name or '' # will return Partner Title + Partner Name(Mr. Openies)

    merged_string = fields.Char(compute='merge_string') # adding one field which merges string

Note: Compute field will get computed when the record is getting saved.

you can also refer the odoo new api doc: http://odoo-new-api-guide-line.readthedocs.org/en/latest/fields.html#computed-fields