Re: bitand functions and NUMBER(20)
- From: Stefan Kuhn <skuhn@xxxxxxxxxxxx>
- To: oracle-l@xxxxxxxxxxxxx
- Date: Thu, 19 Jul 2007 14:52:31 +0200
On Thursday 19 July 2007 14:44, Kerber, Andrew W. wrote:
> I have to ask this question because no one has yet given me an answer. Why
> do you use an Oracle database to store bitwise data? Any performance gain
> you might possible get by doing bitwise operations is going to be
> completely overshadowed by the retrieval time from the database.
What is the alternative? Hold the bitset in memory by the appliation? That
makes it necessary to synchronize this cache and it's not that nice to query.
Btw, the bit functions take milliseconds even on a few hundred thousand
entries - that's no too bad, I would say.
>
> -----Original Message-----
> From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx]
> On Behalf Of Stefan Kuhn Sent: Thursday, July 19, 2007 7:18 AM
> To: oracle-l@xxxxxxxxxxxxx
> Subject: bitand functions and NUMBER(20)
>
> Hi all,
> I have got a column defined as NUMBER(20) and want to use bit functions on
> it. It seems that oracle bitand function is restricted in length. To give
> an example:
> select bitand(10846370260800065548,9368617832122679304) from TABLE;
> returns 9.2234E+18, although the second figure is a subset of bits in first
> figure. So result should be 9368617832122679304.
> To make sure my figures are right, I did
> select 10846370260800065548 & 9368617832122679304;
> in Mysql and it gave 9368617832122679304.
> The problem does arise with figures of a certain length.
> What to do best (apart from changing the column type, which I would like to
> avoid)?
> I hope the question isn't too trivia...
> Stefan
--
Stefan Kuhn BSc MA
IPB Halle
AG Bioinformatik & Massenspektrometrie
Weinberg 3
06120 Halle
http://www.ipb-halle.de http://msbi.bic-gh.de
skuhn@xxxxxxxxxxxx Tel. +49 (0) 345 5582 1474 Fax.+49 (0) 345 5582 1409
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