Re: Use of regular expression

[Charles Wilt <charles.wilt@xxxxxxxxx>]

Rick,

neither Reg-ex or standard SQL are going to give you decent
performance....as either way 1 billion records would have to be read.
I do agree with Jon that SQL should have the edge.

Your best option, if at 6.1 or 7.1, is the OmniFind text search
product; which is a no-charge option at those releases.
http://www-304.ibm.com/partnerworld/wps/servlet/ContentHandler/whitepaper/i/omnifind/search
http://publib.boulder.ibm.com/infocenter/iseries/v6r1m0/topic/rzash/rzash.pdf

If you're on v5r4 (or earlier), OmniFind's predecessor is the
chargeable 5722-DE1 Text Extender product.
http://publib.boulder.ibm.com/infocenter/iseries/v5r4/topic/books/sh126720.pdf

Lastly, OmniFind and Text Extender work by building special indexes.
You could conceivably roll your own version....but I'd be willing to
bet you'd wish you'd have just bought the software! :)


Charles




On Fri, Jul 16, 2010 at 5:06 PM,  <Rick.Chevalier@xxxxxxxxxxxxxxx> wrote:
> I'm wondering if using regular expressions is a good way to handle a word search.  What I need is an exact match of a series of characters, say 'rick', in a character field.  I have only used regular expressions a couple of times and the syntax still gets me confused.  I think I see a way to do this with with something like r{1}i{1}c{1}k{1}.
>
> I know I can do this with the %SCAN op code.  The reason I'm thinking about using regular expressions is the search will be over a table of close to 1 billion records and I'm looking for efficiencies any place I can find them.  If an expression can be created I want to do some comparisons between using a regular expression and %SCAN to see which is really the best performer.
>
> Any thought would be appreciated.
>
> Rick Chevalier
> IT Software Solutions - Loan Servicing
>
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