[Dbix-class] Prefetch Problem: Related data can't be fetched

[Matt Lawrence]

sindharta_tanuwijaya at yahoo.co.jp wrote:
> Hi,
>
> I am having a problem, in which I couldn't get the relationship column
> data by using prefetch.
> My relationship is declared like this, suppose we have two tables:
> railway and railway_station, which relationship is 1 to many.
>
> #in railway schema
> __PACKAGE__->has_many(
> "railway_station",
> "Schema::RailwayStation",
> { "foreign.railway_station_railway_id" => "self.railway_id" },
> );
>
> #in railway_station schema
> __PACKAGE__->belongs_to(
> "railway",
> "Schema::Railway",
> { "foreign.railway_id" => "self.railway_station_railway_id" },
> );
>
> My prefetch command is as follows:
>
> my $railways = $schema->resultset('Railway')->search(
> {
> 'me.railway_id' => { 'IN' => $selected_railway_ids },
> },
> {
> join => 'railway_station',
> prefetch => 'railway_station',
> }
> );
>
railway_station is a has_many relationship, so you can't prefetch it.
You could do it the other way around and prefetch "railway" from a
RailwayStation resultset however:

my $railways = $schema->resultset('RailwayStations')->search({
'railway.id' => { -in => $selected_railway_ids },
}, {
prefetch => 'railway',
});


Matt