Quite right, as the following code shows:

use strict;
use warnings;

package Foo;
use base 'Class::DBI';
__PACKAGE__->connection( 'dbi:SQLite:dbname=db_file', '', '' );
__PACKAGE__->table('foo_table');
__PACKAGE__->columns( All => qw/id name/ );
# create table foo_table ( id integer primary key, name char(10) );
1;

package main;

use Test::More 'no_plan';

# In test suite.
my $cdbi_object = Foo->create( { name => 'Foo' } );

# Check CDBI object is as expected.
is $cdbi_object->name, 'Foo', "name is correct (Foo)";

# Change the name through web site.
ok( Foo->db_Main->do("update foo_table set name = 'Bar'"),
    "update name to 'Bar'" );

# undef and reload object.
ok my $cdbi_id = $cdbi_object->id, "get id";
$cdbi_object = undef;
ok $cdbi_object = Foo->retrieve($cdbi_id), "retrieve object";

# Check that the name has changed.
is $cdbi_object->name, 'Bar', "name has changed to 'Bar'";

ok( $_->delete, "delete object" ) for Foo->retrieve_all;
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Still it would b e nice if this could be done more easily with something like $object->freshen.

1. Create an object.
2. Store it.
3. Retrieve it into some variable a.
4. Retrieve it again into some variable b.
5. A change to a won't change b?

All of the perl ones work that way, except for the latest version of Class::DBI which does some tricks with an index of loaded objects and weakrefs to avoid this. And that has caused so many user complaints that I'm hoping to turn it off in the next release.

ORM or not, once you retrieve data from the database and hold it in a variable, it has no way of knowing that the underlying database has been changed. This usually doesn't matter since the data is kept in variables for only a short time. Where it does matter, people have to use locking schemes to deal with it.

Thanks for the info on Class::DBI.

But it really depends on the ORM. Having delt with ones inside and outside of perl, EJB and I think Hibernate both support multiple instances of an object, but modifying one means you modify the other for persistable things. Hibernate doesn't do it as thoroughly as EJB.

I'm really surprised it has caused complaints. What have you been told?

-s

----
Give me strength for today.. I will not talk it away..
Just for a moment.. It will burn through the clouds.. and shine down on me.