Re: Db2, Oracle, SQL Server

"Serge Rielau" <srielau_at_ca.ibm.com> wrote in message news:36nqruF4vd94lU1_at_individual.net...
>
> Valentin Minzatu wrote:
>
> > I would like not to be the match, but to get answers.
> I tried hard. And I waive counter questions. But in return I'll provide
> details so we all learn instead.
>
>> Just to add on the "Oracle's the best" item list:
>> - Data Guard/Streams support DDL, while DB2's corresponding feature does
>> only support DML
> Correct for replication only. I'm told Data Guard is best compared with
> HADR. HADR stubbornly applies all logs, including catalog changes.
> Thus it covers all DDL. HADR comes in three flavors: Asynchronous,
> near-synchronous and synchronous. If Informix is any judge most customers
> will use near-synchronous.
> In that case the primary server waits for the seondary to acknowledge
> receipt of a log record. To loose a transaction the secondary and primary
> have to die simultaneously.
> Asynchronous means that the primary puts the log on the wire and trusts in
> the network. Synchronous means the secondary confirms persistence of the
> log.

That does sound analogous to DataGuard, Streams is a somewhat different technology IMO, I have no idea whether IBM has anything similar. Whilst both technologies deal with data moving from one place to another - streams is about doing workflow across systems (in my view anyway) not about replication for HA or DR. There is a very good intro at http://www.oracle.com/technology/products/dataint/htdocs/streams_fo.html which may confirm whether I'm talking garbage or not.

>> - Does DB2 provide with any functionality similar to Oracle's external
>> tables?
> Capability I think (?) yes for reads. DB2 supports external table UDF.
> There is no CREATE TABLE language hooking directly into the load facility.
> I don't know what Oracle's write capabilities are.

They are there in 10, but I'm not impressed. You can load from any flat file format, the 'flat file' that gets written to is in Oracle 'proprietory' format. (i.e no choice of .csv tab delimited or whatever. )

-- 
Niall Litchfield
Oracle DBA
http://www.niall.litchfield.dial.pipex.com