Question on DBI module?

[sangith]

Hi,
I am interacting with the database through use DBI module. Please take a look at the follwoing:

#I am querying the database for the name and age information
 
$sth = $dbh->prepare(q{SELECT name, age FROM group});
 
#Using the while loop I am printing the information on the screen:
 
my @row;
while (@row = $sth->fetchrow_array()){
    print "ROW:@row\n";
}
 

I am seeing the information of name and age on the output screen (which I got from querying the db) when I run this program.
But I want to store the same information in a file.

Can anyone please let me know how to store the same information to a file.

Thanks in advance!
Sangith

[miller]

Sangith,

This question isn't about the DBI module at all. It's about outputting to a file. There are many ways to do this, what type of spec are you trying to satisfy?

cpan Text::CSV

use Text::CSV;
 
use strict;
 
...
 
my $outfile = 'group.csv';
 
my $sth = $dbh->prepare(q{SELECT name, age FROM group});
$sth->execute or die $dbh->errstr;
 
open(OUT, ">$outfile") or die "Can't open $outfile: $!";
$csv = Text::CSV->new();
 
while (my @row = $sth->fetchrow_array()){
    if ($csv->combine(@row)) {
        print OUT $csv->string(), "\n";
    } else {
        die "combine() failed on argument: ", $csv->error_input, "\n";
    }
}
 
close(OUT);
 
$sth->finish; undef $sth;
 

- Miller

[sangith]

Hi Miller,

I totally understand that outputting to a file is completely independant of DBI module. That can be done in various ways. Using Text::CSV, or can use a file handle to output to an output file, etc

I appreciate your quick response! The program you sent me works just fine. I have just started using Perl modules in my program. I have few questions related to Modules.

I was reading "Programming Perl" book to get a good knowledge on Modules. But they are talking about object construction, class Inheritance, Overloading, Tied variables,......That looks very complicated to me.

I am not going to create modules/Packages. I am just going to use different modules in my Perl programs.
So for using the modules in my program, what should I know and what should I read about?
Because although I use modules, I don't really understand what I am passing to the modules, what '->' means ,..........(Its totally not clear)
Can you please point me to any document/resources on using Modules.
I would appreciate your advice!

Thanks in advance!
Sangith

[KevinADC]

Most modules have documentation that explains how to use them. Some explain better than others. You can look up modules by their name on cpan:

http://search.cpan.org/

[sangith]

Most modules have documentation that explains how to use them. Some explain better than others. You can look up modules by their name on cpan:

http://search.cpan.org/

Thank you for your response.

-Sangith

[miller]

I totally understand that outputting to a file is completely independant of DBI module. That can be done in various ways. Using Text::CSV, or can use a file handle to output to an output file, etc

I chose to demonstrate the Text::CSV module to you simply because if you are going to output records to a file, it makes sense that you be able to load them easily again. A csv file is a very standard format, so could easily be imported into many other applications, such as a Spreadsheet for example.

I have few questions related to Modules.
...
So for using the modules in my program, what should I know and what should I read about?
...
Can you please point me to any document/resources on using Modules.
I would appreciate your advice!

As Kevin pointed out, cpan is often the best place for documentation about modules that you will use. Another resource is perldoc:

http://perldoc.perl.org/

There are a lot of Core Modules that are included in perl, so it's good to at least be aware of them if not familiar. There are also a lot of tutorials available along with other documentation. So perldoc is typicaly the first place I look for information.

Good Luck.
- Miller