Toad World® Forums

'Default Rule' and 'Rules' in Attribute Properties in TOAD DM


#1

Hello,

I don’t think I quite understand how to use the concept of the ‘Default Rule’ or ‘Rules’ in the ‘Attribute Properties’ dialog box. I see where I can add a Default Rule name (in the ‘General’ tab), but I don’t see where I put in any actual Default Values. Also, under the ‘Rules’ tab in the ‘Attribute Properties’ dialog box, I don’t see how to even add a ‘Rule’ at all - what is the ‘Rule’ that is being referred to here and how is it used? If there is some documentation to point to, that would be great - it may just be that I’m not understanding the intent of these properties and in what context they are used.


#2

Hello Patrick,

let me explain the benefit of Default Rules:

In your database structure, you might need to use the same default value in multiple attributes in various entities. Let’s say we have entities Customer, Order, Address, DeliveryType and so on. In some of the entities we have attributes IsActive and IsValid and some others. For all the attributes IsActive we want to use default value ‘Yes’. Instead of specifying the value on each attribute, we can use Default Rule and assign the default rule to the attributes. See the following screenshot and see how the default value is propagated from the Default Rule to the Default field (grayed out).

default-rule.png

If we decide to change the default value from Yes to Y, we can do the change just once, in the Default Rule specification.

I hope it helps,

Vaclav