Re: constraints on views

mystery solved... they are read only constraints.


On Mon, Jul 4, 2011 at 1:39 PM, Patrice sur GMail
<patrice.boivin@xxxxxxxxx>wrote:

> I found a schema with over a hundred constraints on views...not tables.
>
> -----
> View Constraints Oracle Database does not enforce view constraints.
> However, you can enforce constraints on views through constraints on base
> tables.
>
> You can specify only unique, primary key, and foreign key constraints on
> views, and they are supported only in DISABLE NOVALIDATE mode. You cannot
> define view constraints on attributes of an object column.
>
> http://download.oracle.com/docs/cd/B19306_01/server.102/b14200/clauses002.htm
>
> ------
>
> That passage isn't clear to me -- does it imply that constraints on views
> can be created but never enforced?
> How can that be useful?
>
> If that is the case, I can't understand why someone would create a
> constraint on a view instead of on the base tables.
>
> No idea how these were created, maybe they were imported from Access or
> some other environment.
>
> Patrice.
>



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