Re: Replacing a view with selects on it
- From: "jaromir nemec" <jaromir@xxxxxxxxxxxx>
- To: <oracle-l@xxxxxxxxxxxxx>
- Date: Mon, 17 May 2004 23:52:20 +0200
Thanks Daniel, Wolfgang and Justin,
@Daniel - I didn't consider a change of a view *structure*. I meant only a
change of the data selected in the view, e.g. a change of the where clause
in the view. From this point of view the only *repeatable read* requirement
is, that the select don't crash or return wrong result if the view is
replaced while performed.
@Wolfgang - good point; the only access of the view while parsing the
query - but what happen if the query gets out from library cache and needs
to be reparsed?
Could there be a situation that it cause some troubles?
@Justin - yes I admit that the safest way is to perform the change direct
with DML. The database guaranties that all is transactional safe. But e.g.
in case if you have a massive change in a big snapshot it could be
preferable to *prepare* the change in stage area and to *publish* the new
version of this snapshot via a replacement of a view (e.g. exchange
partition and repointing the access view to the new partition)
regards
Jaromir D.B. Nemec
----- Original Message -----
From: "Daniel Fink" <Daniel.Fink@xxxxxxx>
>There is one problem with this that I can see. By changing the view while
another session has referenced it, you invite the
>possibility of a non-repeatable read.
----- Original Message -----
From: "Wolfgang Breitling" <breitliw@xxxxxxxxxxxxx>
>Unless my understanding is utterly wrong, the view definition is only
>required during the parsing of the query.
----- Original Message -----
From: "Justin Cave (DDBC)" <jcave@xxxxxxxxxxx>
>My preference in this sort of environment would be to replace the data
>in a single transaction,
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