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RegEx for DBAs


RegEx for DBAs

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David.Poole
David.Poole
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Comments posted to this topic are about the item RegEx for DBAs

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rraja
rraja
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Very nice Article.:-)
david.rowland
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Although RegEx is powerful, I have tried using it once and found that coding my own CLR function to manipulate strings to what I want was 100 times faster than the RegEx function was.

If you are running the code against a small dataset this should not matter however I was running the code against millions of rows and this had a major impact on performance.
Jeff Moden
Jeff Moden
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Great and very nicely put together article, David. My hat is off to you. But what of performance? Have you done any comparisons between the Regex function and a moderately complex PatIndex?

--Jeff Moden

RBAR is pronounced ree-bar and is a Modenism for Row-By-Agonizing-Row.
First step towards the paradigm shift of writing Set Based code:
Stop thinking about what you want to do to a row... think, instead, of what you want to do to a column.
Although they tell us that they want it real bad, our primary goal is to ensure that we dont actually give it to them that way.
Although change is inevitable, change for the better is not.
Just because you can do something in PowerShell, doesnt mean you should. Wink

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Jeff Moden
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david.rowland (5/7/2012)
Although RegEx is powerful, I have tried using it once and found that coding my own CLR function to manipulate strings to what I want was 100 times faster than the RegEx function was.

If you are running the code against a small dataset this should not matter however I was running the code against millions of rows and this had a major impact on performance.


What did your custom CLR do to beat Regex so soundly?

--Jeff Moden

RBAR is pronounced ree-bar and is a Modenism for Row-By-Agonizing-Row.
First step towards the paradigm shift of writing Set Based code:
Stop thinking about what you want to do to a row... think, instead, of what you want to do to a column.
Although they tell us that they want it real bad, our primary goal is to ensure that we dont actually give it to them that way.
Although change is inevitable, change for the better is not.
Just because you can do something in PowerShell, doesnt mean you should. Wink

Helpful Links:
How to post code problems
How to post performance problems
Forum FAQs
corey lawson
corey lawson
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I've used our own in-house implementations of some of the .Net RexEx functions on seemingly large datasets (several million records each), mostly to help clean up, validate and parse addresses, city-state-zip (or province), etc.

Beats pure SQL functions like Hulk did to Loki in the movie, especially in understandability. I'll take teasing a complicated Rexex pattern over scads of nested SQL functions trying to do the same thing.

one I really have done lots of is to do is keep expanding on a pattern like this: '(Company|corp|corporation|inc|llp|llc...)'

beats continuing to add "or field like '%new_match%' ..."
borisk 57245
borisk 57245
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RegEx is Thee best tool in order to find any pattern within given string[did couple of test including .Net String manipulation and limited RegEx in SQL , Like/PATIndex....], and it proves to be much faster than any other way.
in regards to good editor, try this one: http://www.ultrapico.com/Expresso.htm

moreover, consider using FullText indexing from time to time, as it might even ease searching for Words other than using RegEx.
Jeffrey Bijkerk
Jeffrey Bijkerk
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If you use regex combined with a where clause it can not use the index anymore. I think this is very important.
williams.frd
williams.frd
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Am I out of line in thinking this is something that should be handled in a high-level object-oriented language?
paul.knibbs
paul.knibbs
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I'm not particularly familiar with the CLR--does processing stuff via RegEx in this way effectively mean you're using RBAR, or is it a bit cleverer than that?
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