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Re^2: Fetch Mysql huge database

by ym_chaitu (Initiate)
on Sep 29, 2011 at 11:05 UTC ( [id://928520]=note: print w/replies, xml ) Need Help??


in reply to Re: Fetch Mysql huge database
in thread Fetch Mysql huge database

Hai Thank you for taking time and giving me a reply. But the script which as given here didn't showed the expeted results. i have changed your script and worked on a test database first it gave one error in the partNames.pl so i have changed the my $c =  substr $, 0, 1; line to my $c =  substr $_, 0, 1; something like this. then it started working but it stored all the values from the table into one file called as "names" even with the column name and the duplicate values. then when i ran the uniqNames.pl script i didnt got any result the file created is of 0KB. can you kindly help me on this. Once again Thank you for your reply. Pardon me if there are any mistakes

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Re^3: Fetch Mysql huge database
by BrowserUk (Patriarch) on Sep 29, 2011 at 11:19 UTC
    didn't showed the expeted results.

    I did warn that the code was untested.

    i have changed the my $c = substr $, 0, 1; line to my $c = substr $_, 0, 1;

    Correct correction :)

    but it stored all the values from the table into one file called as "names"

    I assigned the first char to a variable $c, but then used $char everywhere else.

    You should have received a message: Name "main::char" used only once: possible typo ...?

    I've updated the post above to correct the errors you've pointed out, but there may be more.


    Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
    "Science is about questioning the status quo. Questioning authority".
    In the absence of evidence, opinion is indistinguishable from prejudice.
      Hai Thank you again for your reply. i have modified your script and this worked out for me. Here is the script that i have used. partNames.pl
      while( <> ) { my $c = substr $_ ,0, 1; #print "C value --> ".$c."\n"; $file = "names".$c; &file_write($file,$_); } sub file_write(){ $_file = shift; $_data = shift; open (DATA_FILE,">>$_file") or die("Cannot open a file $_file ->$!\n" +); print DATA_FILE "$_data"; close(DATA_FILE); }
      uniqNames.pl
      for my $fname ( glob 'names*' ) { my %uniq; open my $fh, '<', $fname or die $!; while( <$fh> ) { print unless exists $uniq{ $_ }; $uniq{ $_ } = 1; } }
      Thank you once again for your help.
        . i have modified your script and this worked out for me.

        Be aware. Whilst what you've posted will work, re-opening and closeing your files for every line you write to them will make your program run 100 times more slowly. And it is completely unnecessary.


        Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
        "Science is about questioning the status quo. Questioning authority".
        In the absence of evidence, opinion is indistinguishable from prejudice.

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