Say you want to store configuration data in a database, such as:

Table: preferences
  +----+------------------+----------------------------+
  | id | name             | value                      |
  +----+------------------+----------------------------+
  |  0 | filename         | /path/to/file.txt          |
  |  1 | item_enabled     | 1                          |
  |  2 | task_name        | something                  |
  +----+------------------+----------------------------+
[download]

but instead of doing:

  my $row=DB::Prefs->search({ name => "filename" })->first;
  print $row->value,$/;
  $row->value("/new/path/to/file");
[download]

you want to set up accessors to point to the row in the database rather than the column:

  print DB::Prefs->filename,$/;
  DB::Prefs->filename("/new/path/to/file");
[download]

which is much easier to use and looks cleaner. All you have to do is create your Prefs class with an AUTOLOAD function, as below:

  package App::Prefs;
  use base 'App';
  use strict;
  __PACKAGE__->table("preferences");
  __PACKAGE__->columns( ALL => qw/ id name value/ );
  
  sub AUTOLOAD {
    my $self = shift;
    my $newval = shift;
    my $attr = our $AUTOLOAD;
    $attr =~ s/.*:://;
    return if($attr eq "DESTROY");
    my $row = $self->search({ name => "$attr" })->first();
    if(defined($newval)) {
      if(!$row) {
        $row=$self->insert({ name => "$attr" });
      }
      $row->value($newval);
      $row->update();
    }
    return defined($row) ? $row->value : undef;
  }
[download]

So calling an accessor with no matching "name" in the preferences table will return "undef", calling an accessor with a parameter will insert that name/value pair into the table, and thereafter calling the accessor will return the correct value for the name matching the accessor

---

---

Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!

Titles consisting of a single word are discouraged, and in most cases are disallowed outright.

Read Where should I post X? if you're not absolutely sure you're posting in the right place.

Please read these before you post! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

	For:		Use:
	&		&
	<		&lt;
	>		&gt;
	[		&#91;
	]		&#93;

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.