Re: Constraint Question - Deferred or Not Deferred?

On 16 Nov 2005 12:43:38 -0800, "art_at_chicagorsvp.com" <art_at_chicagorsvp.com> wrote:

>Hi,
>
>I am having trouble understanding the following states of a constraint:
>
>Initially Immediate
>Initially Deferred
>NoValidate
>
>>From my understandings, Initially Immediate means check the constraint
>as soon as the user hits enter.

more exactly, upon INSERT, UPDATE, DELETE

 Initially Deferred means to check the
>constraint when the user types commit.
>

As soon as a commit is being issued.

>Novalidate, I think, means not to check the data in the table. From
>what I have read, when a constraint is 'Novalidate', it creates a
>non-unique index, I assume to keep track of what was in the table?
>

I don't think so. I'm not aware of automatic non-unique indexes on foreign keys at least.

>If I have a disabled constraint and want to enable it and not check
>what is in the table, can I alter the constraint to Novalidate?
>

Yes
>I also heard of a Reply and NoReply state, which I have not read about
>yet.....
>
>Thanks.

Read that
Rely and NoRely.
Never needed to use it.

--
Sybrand Bakker, Senior Oracle DBA