Re: Sequential data read in MySQL/Perl

Hi justin423,

Having read your question several times, I can't make heads or tails from it. What is the schema of the database table? How do you store REC2 DATA3 DATA4 2 DATAX with 5 columns and RECZ 5 DATAX with 3 columns? Also, what do you mean by (NEW VALUE) ? Why is the first RECZ numbered with 5, but there's no number for the second RECZ?

If you just want to know how to persist a value across several iterations of a loop, the answer is simple: declare a variable before the loop.

#! /usr/bin/perl
use warnings;
use strict;

my $grouping = q();
while (<DATA>) {
    my @columns = split;
    print "@columns $grouping\n";
    if (@columns > 2) {
        $grouping = $columns[1] if q() eq $grouping;
    } else {
        $grouping = q();
    }
}

__DATA__
REC1 DATAX DATA2 1
REC2 DATA3 DATA4 2
REC3 DATA5 DATA6 3
REC4 DATA7 DATA8 4
RECZ 5
REC1 DATAY DATA2 6
REC2 DATA3 DATA4 7
REC3 DATA5 DATA6 8
REC4 DATA7 DATA8 9
RECZ
[download]

($q=q:Sq=~/;[c](.)(.)/;chr(-||-|5+lengthSq)`"S|oS2"`map{chr |+ord
}map{substrSq`S_+|`|}3E|-|`7**2-3:)=~y+S|`+$1,++print+eval$q,q,a,
[download]

Comment on Re: Sequential data read in MySQL/Perl Select or Download Code

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Re^2: Sequential data read in MySQL/Perl by justin423 (Scribe) on Jul 06, 2016 at 22:20 UTC
the table is a temp table that has the fields that are common across all of the rows coming in. (REC1 to RECZ above). the common identifier for REC1 to RECZ only appears on REC1, so i want to update the rec2, rec3, rec4 rows with the value in DATAX, which only appears in REC1. I was also trying to show that the value needs to be reset when the program encounters a RECZ, so that a new value is applied for the next group. How do I read the value from the database into a variable using DBI?	[reply]
Re^3: Sequential data read in MySQL/Perl by Marshall (Canon) on Jul 07, 2016 at 00:16 UTC
I am also confused about what you are doing. If these 9 values "go together" somehow, then perhaps a table like what I show below is what you need? Each row is a "group" and each column contains "like data". Without some descriptive story re: post from Grandfather, its hard to say what you really need (which may be different than what you are asking for). `1 DATAX DATA2 DATA3 DATA4 DATA5 DATA6 DATA7 DATA8 2 DATAY DATA2 DATA3 DATA4 DATA5 DATA6 DATA7 DATA8` [download]	[reply] [d/l]
Re^4: Sequential data read in MySQL/Perl by justin423 (Scribe) on Jul 07, 2016 at 01:12 UTC
That is just about what I am asking for. A script to convert each group I encounter on the source file to be stored in a single row like you have done.	[reply]
Re^5: Sequential data read in MySQL/Perl by Marshall (Canon) on Jul 07, 2016 at 01:41 UTC
Re^6: Sequential data read in MySQL/Perl by justin423 (Scribe) on Jul 07, 2016 at 02:12 UTC
Some notes below your chosen depth have not been shown here
Re^4: Sequential data read in MySQL/Perl by justin423 (Scribe) on Jul 07, 2016 at 01:12 UTC
That is just about what I am asking for. A script to convert each group I encounter on the source file to be stored in a single row like you have done.	[reply]