Re: database integrity

Kenneth Downs wrote:
>
> One question on my mind is the change in rules over time. Do we say:
>
> 1. Data is valid if it adheres to all existing biz rules, OR:
> 2. Data is valid if it adheres to rules that were in force when it was
> inserted or updated.

Very interesting question. I would say that it is the simplest to let the static database constraints be applicable for all the data, and if you want to restrict what can be added (or deleted or updated) then you use dynamic database constraints (or transition constraints, as they are also called) to specify that.

I've always wondered why this is never mentioned as an example of the usefulness of dynamic database constraints.

• Jan Hidders