Re: Assertions Dilemma

Answers embedded
"Sted Alana" <Sted_Alana_at_hotmail.com> wrote in message news:3ccb8372_1_at_news.iprimus.com.au...
>
> >Jonathan Gennick wrote:
> > An immediate constraint is one that is checked immediately after a
> statement executes.
>
> Do you mean after a SQL statement for example? or when you define a table?
>

immediately after
insert
update
delete

>
> >A deferred constraint is one that is not checked until you commit your
> transaction.
>
> Dont understand the term 'commit your transaction'.

Until you issue an explicit commit statement or leave the program, or disconnect, which results in an implicit commit
>
>
> >A deferred foreign-key constraint, for example, will allow you to insert
> child >rows first and the parent row last, and everything will be ok as
long
> as you have it all straight when you commit.

Or run
update emp set empno = empno + 10 (empno 20 *does* exist already)
>
> Ok. This sounds like disabling a contraint and enabling it again when the
> tables have been created.
>

NO
>
> > I don't understand the second part of your question.
>
> The book I am currently reading makes note of assertions with partial
> rollback and rollback.
>

That would sound like lousy practice once you have deferred constraints.
>
>

Hth

--
Sybrand Bakker
Senior Oracle DBA

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