odoo api装饰器 one、model和multi区别

## @api.one

新api定义：

qty = fields.Integer(string="qty", compute="_get_qty")

@api.one
def _get_qty(self):
    self.qty = random.randint(1, 10)

one一般使用再无返回值，就算添加return也不会返回，也不会报错，版本10以后逐渐淡化

## model

新api定义

@api.model
def create(self, vals):
    bom_obj = self.search([("product_tmpl_id", '=', vals.get('product_tmpl_id', None))])
    if bom_obj:
        raise UserError('该产品已存在相应的物料清单')
    return super(MrpBom, self).create(vals)

注意：这个方法的注释是这样的：修饰记录样式的方法，其中``self``是记录集，但和内容无关紧要，只有模型相关

假如上面使用mutil装饰就会出错，提示参数个数的报错， 此方法可以有返回值

def model(method):
    """ Decorate a record-style method where ``self`` is a recordset, but its
        contents is not relevant, only the model is. Such a method::

            @api.model
            def method(self, args):
                ...

        may be called in both record and traditional styles, like::

            # recs = model.browse(cr, uid, ids, context)
            recs.method(args)

            model.method(cr, uid, args, context=context)

        Notice that no ``ids`` are passed to the method in the traditional style.
    """
    method._api = 'model'
    return method

## mutil

新api定义

@api.multi
def search_recursively_line_product(self):
    product_ids = set()
    for rec in self:
        for bom_line in rec.bom_line_ids:
            product_ids.add(bom_line.product_id.id)
            product_tmpl_id = self.env['product.product'].browse(bom_line.product_id.id).product_tmpl_id.id
            bom_line_bom = self.search([('product_tmpl_id', '=', product_tmpl_id)])
            if bom_line_bom.bom_line_ids:
                product_ids |= bom_line_bom.search_recursively_line_product()
    return product_ids

注：mutil和one时对应的，可以返回一个或者回个记录集

修饰一个记录样式的方法，其中``self``是一个记录集，通常定义对记录的操作

def multi(method):
    """ Decorate a record-style method where ``self`` is a recordset. The method
        typically defines an operation on records. Such a method::

            @api.multi
            def method(self, args):
                ...

        may be called in both record and traditional styles, like::

            # recs = model.browse(cr, uid, ids, context)
            recs.method(args)

            model.method(cr, uid, ids, args, context=context)
    """
    method._api = 'multi'
    return method