Just a brief foot-note to this discussion. The reason I selected the data, rather than attempted an automatic correction, was that sometimes two words would be separated by ascii(10) (forcing a line throw), and sometimes the corruption would appear as an additional spurious character in a line. In the former case, one wants to replace ascii(10) with a space (ascii 32), but in the latter case one simply wants to remove the corrupt data character.
OK, yes, I could do it with decode, and I'm sure Jared will have the appropriate Perl script out before I finish typing this.... But but but... peter edinburgh > -----Original Message----- > From: Stephane Faroult [mailto:[EMAIL PROTECTED] > Sent: Friday, October 10, 2003 10:54 PM > To: Multiple recipients of list ORACLE-L > Subject: Re: Find an unprintable character inside a column.... > > > [EMAIL PROTECTED] wrote: > > > > I played with this a bit. > > > > First, I created some test data with one column corrupted with a > > single random character > > of 0-31 replacing a random char in that column 20% of the > rows of the > > table. > > > > Peter's function correctly found all of the rows in 7.5 seconds. > > > > Stephane's function ran in 3.5 seconds, but didn't find any of > > the rows. I didn't attempt to correct the code. > > > > Then I tried a function based on owa_pattern.regex. My initial > > attempts > > didn't return the correct rows, as the regex pattern needed some > > tuning. > > > > I didn't attempt to fix it, as it was woefully slow, about > 30 seconds. > > > > Regex in the WHERE clause in 10g will be nice. > > > > Jared > > > > "Stephane Faroult" > > <[EMAIL PROTECTED]> To: Multiple > > Sent by: [EMAIL PROTECTED] recipients of list ORACLE-L > > <[EMAIL PROTECTED]> > > 10/10/2003 07:09 AM cc: > > Please respond to ORACLE-L Subject: RE: RE: > > RE: Find an unprintable > character > > inside a column.... > > > > >Some people have requested this code, so I thought > > >you might as well all > > >have the chance to pick it to bits... Its a > > >function called BAD_ASCII, and > > >it hunts out for any ascii characters with an ascii > > >value of less than 32 in > > >a specified field. (Acknowledgments to my colleague > > >Keith Holmes for help > > >with this code.) > > > > > >Use it as follows: > > > > > >Where a field called DATA in a table TABLE_1 may > > >contain an ascci character > > >with a value less than 32 (ie a non-printing > > >character), the following SQL > > >will find the row in question: > > > > > >select rowid,DATA,dump(DATA) from TABLE_1 > > >where BAD_ASCII(DATA) > 0; > > > > > >You could use the PK of the table instead of rowid, > > >of course. You will also > > >note that I select the DATA field in both normal > > >and ascii 'dump' mode, the > > >better to locate where the corruption is located. > > > > > >peter > > >edinburgh > > >................................... > > > > > >Source as follows: > > > > > > > > >Function BAD_ASCII > > > (V_Text in char) > > > return number > > >is > > > V_Int number; > > > V_Count number; > > >begin > > >-- > > >V_Int := 0; > > >V_Count := 1; > > >while V_Count<=length(rtrim(V_Text)) and V_Int=0 > > > loop > > > if ascii(substr(V_Text, V_Count, 1))<32 then > > > V_Int := V_Count; > > > end if; > > > V_Count := V_Count + 1; > > >end loop; > > >return V_Int; > > >-- > > >exception > > > when others then > > > return -1; > > >end BAD_ASCII; > > >/ > > > > > > > Peter, > > > > I think that you can make this code 25% faster when the data is > > clean (which hopefully is the general case) by using 'replace', more > > efficient than a PL/SQL loop, to check whether you have some rubbish > > (sort of). It will not tell you where the bad character is, > however - > > which means that then you can loop to look for it. > > > > Here is what I would suggest : > > > > create or replace Function BAD_ASCII (V_Text in char) > > return number > > is > > V_Int number; > > V_Count number; > > begin > > if (replace(V_text, chr(0)||chr(1)||chr(2)||chr(3)|| > > chr(4)||chr(5)||chr(6)||chr(7)|| > > chr(8)||chr(9)||chr(10)||chr(11)|| > > chr(12)||chr(13)||chr(14)||chr(15)|| > > chr(16)||chr(17)||chr(18)||chr(19)|| > > chr(20)||chr(21)||chr(22)||chr(23)|| > > chr(24)||chr(25)||chr(26)||chr(27)|| > > chr(28)||chr(29)||chr(30)||chr(31), > > '--------------------------------') > > = V_text) > > then > > return 0; > > else > > V_Int := 0; > > V_Count := 1; > > while V_Count<=length(rtrim(V_Text)) and V_Int=0 > > loop > > if ascii(substr(V_Text, V_Count, 1))<32 then > > V_Int := V_Count; > > end if; > > V_Count := V_Count + 1; > > end loop; > > return V_Int; > > end if; > > -- > > exception > > when others then > > return -1; > > end BAD_ASCII; > > / > > > Jared, you're the scourge of people who just write things out > of the top > of their head and don't test them thoroughly :-). I had made my usual > mistake of using REPLACE instead of TRANSLATE. Just tried it with > 'regular' data, since this is the only case where it can be > faster that > Peter's routine. > Works like Peter's routine with TRANSLATE, only somewhat faster. > > > Ooops again. > > -- > Regards, > > Stephane Faroult > Oriole Software > -- > Please see the official ORACLE-L FAQ: http://www.orafaq.net > -- > Author: Stephane Faroult > INET: [EMAIL PROTECTED] > > Fat City Network Services -- 858-538-5051 http://www.fatcity.com > San Diego, California -- Mailing list and web hosting services > --------------------------------------------------------------------- > To REMOVE yourself from this mailing list, send an E-Mail message > to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in > the message BODY, include a line containing: UNSUB ORACLE-L > (or the name of mailing list you want to be removed from). 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