Changing the admin edit window display values
- by Henri
I have a database table with e.g. a weight value e.g.
CREATE TABLE product (
id SERIAL NOT NULL,
product_name item_name NOT NULL,
.
.
weight NUMERIC(7,3), -- the weight in kg
.
.
CONSTRAINT PK_product PRIMARY KEY (id)
);
This results is the model:
class Product(models.Model):
.
weight = models.DecimalField(max_digits=7, decimal_places=3, blank=True, null=True)
.
I store the weight in kg's, i.e. 1 kg is stores as 1, 0.1 kg or 100g is stored as 0.1
To make it easier for the user, I display the weight in the Admin list display in grams by specifying:
def show_weight(self):
if self.weight:
weight_in_g = self.weight * 1000
return '%0f' % weight_in_g
So if a product weighs e.g. 0.5 kg and is stored in the database as such, the admin list display shows 500
Is there also a way to alter the number shown in the 'Change product' window. This window now shows the value extracted from the database, i.e. 0.5. This will confuse a user when I tell him with the help_text to enter the number in g, while seeing the number of kgs.
Before saving the product I override save as follows:
def save(self):
if self.weight:
self.weight = self.weight / 1000
This converts the number entered in grams to kgs.
