Arunbear has asked for the wisdom of the Perl Monks concerning the following question:

Dear monks,

Say you already have a sub which creates a database handle e.g. 

sub connect
{
   my $dbh = DBI->connect(
    $dsn,
    $user, 
    $passwd,
    {PrintError => 0}
   ) 
   or Exception::Database->throw($DBI::errstr);
   $dbh->{HandleError} = sub {  Exception::Database->throw($_[0]) };
   return $dbh;
}

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, is there a way to use that when setting up Class::DBI classes?

thanks.

Replies are listed 'Best First'.
•Re: Setting up Class::DBI classes with existing $dbh
by merlyn (Sage) on Dec 09, 2003 at 21:44 UTC
    From the Class::DBI manpage: 
           Dynamic Database Connections

       It is sometimes desirable to generate your database connection 
+informa-
       tion dynamically, for example, to allow multiple databases with
+ the
       same schema to not have to duplicate an entire class hierarchy.

       The preferred method for doing this is to supply your own db_Ma
+in()
       method rather than calling set_db(). This method should return 
+a valid
       database handle.

       Note however that this is class data, and that changing it may 
+have
       unexpected behaviour for instances of the class already in exis
+tence.

    [download]
    I've used this for my own code so that forked kids get their own $dbh, for example.

    -- Randal L. Schwartz, Perl hacker
    Be sure to read my standard disclaimer if this is a reply.

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Re: Setting up Class::DBI classes with existing $dbh
by hanenkamp (Pilgrim) on Dec 09, 2003 at 21:46 UTC

    You might want to look through the Class::DBI and Ima::DBI documentation, specifically the section called "Dynamic Database Connections" in Class::DBI. You can define your own db_Main() method that returns your DBI connection rather than using set_db() directly. I've never done this, but this should work without a hitch. That is,

    package MyClass;
use base 'Class::DBI';

# Stuff....

sub connect {
    # ....
}

sub db_Main() {
    return connect;
}

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Re: Setting up Class::DBI classes with existing $dbh
by jeffa (Bishop) on Dec 09, 2003 at 21:48 UTC
    You can use the code, but i don't think you can use the sub like that. I think you have to set up a DBI class first, maybe something like this: 
    package Foo::DBI;

use base qw(Class::DBI);
use Exception::Database;

Foo::DBI->set_db(
   qw(Main DBI:vendor:database:host user pass),
   {
      RaiseError  => 1,
      PrintError  => 0,
      HandleError => sub {Exception::Database->throw($_[0])},
   },
);

1;

    [download]
    will work for you. I haven't used Exception::Database, however. But i think that will work.

    UPDATE:
    fixed some code typos from cut-n-paste (must preview more ...)
    looks like i was wrong ... but i would create a class anyway ... "when in Rome"

    jeffa

    L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)
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Re: Setting up Class::DBI classes with existing $dbh
by perrin (Chancellor) on Dec 10, 2003 at 17:31 UTC
    Be careful. Although the other answers here are correct, it is easy to run into trouble if the $dbh you provide is not a subclass of Ima::DBI. For example, calling dbi_commit() on your Class::DBI class will not work with the current release of Class::DBI unless your $dbh is an Ima::DBI subclass.
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