Hi,<br>
<br>
My friend solved the problem. It's weird though and I am still a little bit confused. The way I am trying to access/display the rows is like this:<br>
<br>
[% FOREACH railway = railways -%]<br>
[% railway.railway_station.railway_station_fields %]<br>
[% END -%]<br>
<br>
And as Nigel pointed out,<br>
<pre><font size="3"><tt><tt>> Single object which returns an array from the has_many accessor.</tt></tt></font></pre>If I use 'join' only, I could get all the data for railways which only have 1 row of railway_station by using "railway.railway_station", but for railways which have more than 1
rows of railway_station, I had to use something like "railway.railway_station.0". But it always failed for "prefetch"<br>
<br>
The way I wanted it, is that, since my search code is like this,<br>
<br>
my $railways = $schema->resultset('Railway')->search(<br>
{<br>
'me.railway_id' => { 'IN' => $selected_railway_ids },<br>
'railway_station.main_flag' => 1, ## forgot to mention this earlier<br>
},<br>
{<br>
join => 'railway_station',<br>
prefetch => 'railway_station',<br>
}<br>
);<br>
$c->stash->{railways} = [$railways->all];<br>
<br>
<br>
And although railway has 'has_many' rel, with the condition main_flag=1, only 1 or null railway_station should be returned for each railway, and therefore, I am hoping to access it by [% railway.railway_station%]<br>
<br>
The way that my friend solved it, was to declare a select variable<br>
<br>
my @select = (<br>
qw/ <br>
railway_field_1<br>
railway_field_2<br>
main_flag #from railway_station<br>
railway_station_field1 #from railway_station<br>
/<br>
);<br>
<br>
and put it in the search condition like this:<br>
<br>
my $railways = $schema->resultset('Railway')->search(<br>
{<br>
'me.railway_id' => { 'IN' => $selected_railway_ids },<br>
'railway_station.main_flag' => 1, ## forgot to mention this earlier<br>
},<br>
{<br>
select => \@select,<br>
join => 'railway_station',<br>
}<br>
);<br>
<br>
and he wasn't using prefetch at all. Now, I could access 'main flag' field by using [% railway.main_flag.%], instead of <br>
[% railway.railway_station.main_flag %]<br>
Any ideas why this happened?<br>
<br>
Sindharta<br>
<br>
<br>
<b>Jess Robinson <castaway@desert-island.me.uk></b> wrote:<blockquote class="replbq" style="border-left: 2px solid rgb(16, 16, 255); margin-left: 5px; padding-left: 5px;"> <br>
On Tue, 26 Feb 2008, sindharta_tanuwijaya@yahoo.co.jp wrote:<br>
<br>
> Hi,<br>
><br>
> I am having a problem, in which I couldn't get the relationship column data by using prefetch.<br>
> My relationship is declared like this, suppose we have two tables: railway and railway_station, which relationship is 1 to many.<br>
><br>
> #in railway schema<br>
> __PACKAGE__->has_many(<br>
> "railway_station",<br>
> "Schema::RailwayStation",<br>
> { "foreign.railway_station_railway_id" => "self.railway_id" },<br>
> );<br>
><br>
> #in railway_station schema<br>
> __PACKAGE__->belongs_to(<br>
> "railway",<br>
> "Schema::Railway",<br>
> { "foreign.railway_id" => "self.railway_station_railway_id" },<br>
> );<br>
><br>
> My prefetch command is as follows:<br>
><br>
> my $railways = $schema->resultset('Railway')->search(<br>
> {<br>
> 'me.railway_id' => { 'IN' => $selected_railway_ids },<br>
> },<br>
> {<br>
> join => 'railway_station',<br>
> prefetch => 'railway_station',<br>
> }<br>
> );<br>
><br>
> I could get the values of the columns of the railways correctly, but not the columns of railway_stations.<br>
<br>
You don't tell us *how* you are trying to get the columns of the railway <br>
stations, so I really cant tell you where you have gone wrong. Your search <br>
code is correct.<br>
<br>
You can check what SQL it actually runs and try it for yourself, by <br>
setting DBIC_TRACE=1 in your test script environment.<br>
<br>
> If I use 'join' only though, I could get all the data for railways which only have 1 row of railway_station, but not for<br>
> railways which have more than 1 rows of railway_station.<br>
> Any ideas why this happened ?<br>
<br>
Sounds like you are accessing the data incorrectly.<br>
<br>
> I have a hunch that maybe it's the ID of the railway_station that is causing this problem. In our current database, the primary key of<br>
> railway_station works as a dummy field, in which there are a lot of null values (although they are primary keys).<br>
> Of course, I have my own objections to this current implementation, but I am wondering if that is indeed the problem, since the primary key of railway_station isn't supposed to be used in any query generated above ?<br>
<br>
Well, it wont fetch the ones with null relation values, obviously.. but <br>
would you expect it to?<br>
<br>
> Or maybe I am missing something else here.<br>
<br>
Like giving us your code? ;)<br>
<br>
Jess<br>
<br>
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