ValueError Expected singleton in Odoo

Expected Singleton:

Class methods required single invoking object (Single Browsable Record) to invoke the method and suppose it will call by multiple invoking objects (Browsable Recordsets) then method is not able to identify for which object it should process, therefore it will raise an error Expected Singleton.

New API decorator is used to define method calling pattern whether methods allows only single object or multiple objects to invoke this method.


For Example:


if self.location_id:     #face ValueError Expected singleton because self contains multiple recordset.
 
    ########

Need to change with following:

for warehouse in self:

    if warehouse.location_id:

        ########


@api.one

This decorator loops automatically on Records of RecordSet for you. Self is redefined as current record

Note:

Caution: the returned value is put in a list. This is not always supported by the web client, e.g. on button action
methods. In that case, you should use @api.multi to decorate your method, and probably call self.ensure_one() in
the method definition.

@api.multi

Self will be the current RecordSet without iteration. It is the default behavior (multiple browsable objects). Methods which returns non premitive type data(list, dictionary, function) must be decorated with @api.multi 

@api.model

This decorator will convert old API calls to decorated function to new API signature. It allows to be polite when
migrating code. Self does not contain any record/recordset in methods which are decorated by this decorator.

So simply call like this

self.env['model_name'].method_name(arguments)

How to create server actions in Odoo 10?

Below is example of server actions in Odoo 8.

<?xml version="1.0" encoding="utf-8" ?>
<odoo>
    <data>
        <record id="action" model="ir.actions.server">
            <field name="name">My Action</field>
            <field name="model_id" ref="model_module_model"/>
            <field name="code">self.action(cr, uid, context=context)</field>
       </record>
    </data>
</odoo>

Following is example for Server actions in Odoo 10.

<?xml version="1.0" encoding="utf-8" ?>
<odoo>

    <data>
        <record id="action" model="ir.actions.server">
            <field name="name">My Action</field>
            <field name="model_id" ref="model_module_model"/>
            <field name="code">
           
            if context.get('active_model') == 'your.module.model' and context.get('active_ids'):
                    action = env['module.model'].browse(context['active_ids']).action()
          
            </field>
       </record>
    </data>
</odoo>


There is no need of self variable to declare server action in Odoo 10.

How to activate the developer mode in Odoo version 10?

Developer mode has moved from the user screen to Settings.

Click on link "Active the developer mode" or "Active the developer mode (with assets)"

Active Developer mode

What is different between "Active the developer mode" or "Active the developer mode (with assets)" ?

Active the developer mode :- Used by Administrator User to enables Menus, Fields, kind of security access rights.


Active the developer mode (with assets) :- Used by Odoo developers to track js, css, files, which will helpful to improve further performance.

How related field work in Odoo 8, 9, and 10?

Let's take an example of Sale Order Line. Scenario is like when we add Product in sale order line at time, the Product Category name should be fill up. For that we need to do two  things.

1. add related field in 'sale.order.line' and give it in view at proper place
2. need to override onchange of product, if we don't want to override the onchange than at the time of record save it will also save the product category name.

Here is .py code:

Old API:

class sale_order_line(osv.Model):
    _inherit = 'sale.order.line'

    _columns = {
        'product_categ_name': fields.related('product_id', 'categ_id', 'name', type='char', string='Product Category', store=True, readonly=True),
}

New API:

from openerp import api, fields, models, _

class SaleOrderLine(models.Model)
    _inherit = 'sale.order.line'

    product_categ_name = fields.Char(related='product_id.categ_id.name', string='Product Category', store=True, readonly=True)

Here is .xml file

<?xml version="1.0" encoding="utf-8"?>
<openerp>
    <data>
   
        <record id="view_product_category_related_sale_line" model="ir.ui.view">
            <field name="name">view.product.category.related.sale.line</field>
            <field name="model">sale.order</field>
            <field name="inherit_id" ref="sale.view_order_form" />
            <field name="arch" type="xml">
                <xpath expr="//field[@name='order_line']/form/group/group/field[@name='product_id']" position="after">
                    <field name="product_categ_name"/>
                </xpath>
            </field>
        </record>

    </data>
</openerp>


Here is screen shot of it

More about on related field, take a look here

I hope you like this article. Share your views to improve content. Happy Learning !!!

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How to create constraints in OpenERP v7, Odoo 8,9, and 10 ?

This will help you to create a constraints in OpenERP.

_constraint is a pre-define field in OpenERP. It is used for adding a constraint on the object.

It takes list of tuple as its argument. The tuple inside the list contains three parameter.

1. Method (to check the constraint)
2. The Message (Pop-up message for End User)
3. List of Fields (fields to apply the constraint)

_constraint will fire if the condition returns False on creation and updation of the record and display the message.

Here is an example of integer data-type. It's fire a constraint if length is not positive.

Here is .py side code:

Old API:
 
from openerp.osv import fields, osv
class res_partner(osv.Model):
    _inherit = 'res.partner'

    _columns = {       
        'length': fields.integer('Length', size=64),
    }

    def _check_number(self, cr, uid, ids, context=None):
        for partner in self.browse(cr, uid, ids, context=context):
            if partner.length < 0:
                return False
        return True    
   
    _constraints = [
        (_check_length, 'Length must be Positive.', ['length'])
    ]

New API:

from openerp.exceptions import ValidationError
from openerp import api, fields, models, _

class Partner(models.Model):
    _inherit = 'res.partner'

    @api.one
    @api.constrains('length')
    def _check_length(self):
        if self.length < 0:
            raise ValidationError("Length must be Positive.")

    length = fields.integer('Length', size=64)

Here is .xml side code:

<?xml version="1.0"?>
<openerp>
    <data>
        <!-- res partner form view-->
        <record id="view_res_partner_extended_form" model="ir.ui.view">
            <field name="name">res.partner.extended.form.view</field>
            <field name="model">res.partner</field>
            <field name="inherit_id" ref="base.view_partner_form"/>
            <field name="arch" type="xml">
                <field name="email" position="after">
                    <field name="length"/>
                </field>
            </field>
        </record>
    </data>
</openerp>


I hope you like this article. Share your views to improve content. Happy Learning !!!

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