Wednesday, March 17, 2010

KiokuDB ♡ DBIx::Class

I just added a feature to KiokuDB's DBI backend that allows freely mixing DBIx::Class objects.

This resolves KiokuDB's limitations with respect to sorting, aggregating and querying by letting you use DBIx::Class for those objects, while still giving you KiokuDB's flexible schema for everything else.

The first part of this is that you can refer to DBIx::Class row objects from the objects stored in KiokuDB:

my $dbic_object = $resultset->find($primary_key);

    some_id => Some::Object->new( some_attr => $dbic_object ),

The second half is that relational objects managed by DBIx::Class can specify belongs_to type relationships (i.e. an inflated column) to any object in the KiokuDB entries table:

my $row = $rs->create({ name => "blah", object => $anything );


say "Inserted ID for KiokuDB object: ",
To set things up you need to tell DBIx::Class about KiokuDB:
package MyApp::Schema;
use base qw(DBIx::Class::Schema);

# load the KiokuDB schema component
# which adds the extra result sources


package MyApp::Schema::Result::Foo;
use base qw(DBIx::Class);

# load the KiokuDB component:
__PACKAGE__->load_components(qw(Core KiokuDB));

# do the normal stuff
__PACKAGE__->add_columns(qw(id name object));

# setup a relationship column:

# connect both together
my $dir = KiokuDB->connect(
    dsn => "dbi:SQLite:dbname=blah",
    schema_proto => "MyApp::Schema",

my $schema = $dir->backend->schema;

# then you can do some work:
$dir->txn_do( scope => 1, body => sub {
    my $rs = $schema->resultset("Foo");
    my $obj = $rs->find($primary_key)->object;



There are still a few missing features, and this is probably not production ready, but please try it out! A dev release will be out once I've documented it. KiokuDB::Backend::DBI 0.11_01.

In the future I hope to match all of Tangram's features, enabling truly hybrid schemas. This would mean that KiokuDB could store objects in more than one table, with objects having any mixture of properly typed, normalized columns, opaque data BLOBs, or something in between (a bit like DBIx::Class::DynamicSubclass and DBIx::Class::FrozenColumns, but with more flexibility and less setup).

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