Hello Ken Kasai,

This below code may be very helpfull.

create new .xml file

<?xml version="1.0" encoding="utf-8"?>
<openerp>
    <data noupdate="1">
        <record id="test_base_sequence_type" model="ir.sequence.type">
            <field name="name">Test Base Sequence</field>
            <field name="code">test.base.code</field>
        </record>

        <record id="test_base_sequence" model="ir.sequence">
            <field name="name">Test Base Sequence</field>
            <field name="padding">5</field>
            <field name="prefix">TB/%(year)s/</field>
            <field name="suffix">/Ankit</field>
            <field name="code">test.base.code</field>
            <field name="implementation">no_gap</field>
        </record>

    </data>
</openerp>

and create new .py file

class test_base(osv.Model):

      _name = 'test.base'

     _columns = {

           'code' : fields.char("Code", size=25, readonly=True)

     }

    def create(self, cr, uid, vals, context=None):
        sequence = self.pool.get('ir.sequence').get(cr, uid, 'test.base.code')
        vals['code'] = sequence
        res = super(test_base, self).create(cr, uid, vals, context=context)
        return res

if you find this answer helpful, please give me a thumbs up vote    

Regards,

Ankit H Gandhi