has_many confusion using silverstripe ORM -

firstly, forgive scrubbiness , lack of experience in third-party orm's (have gone long "tailor-making" requirements)

i having difficult time understanding relations in silverstripe orm

what i'm trying achieve correlate set of attributes single roomtypeid

/mymodule/models/rooms.php

class rooms extends dataobject {      private static $db = array(         "roomtypeid"        => 'int', // needs correlate attributes.roomtypeid         "roomtypegroupid"   => 'int',         "subpropertyid"     => 'int',         "name"              => 'varchar(255)',         "description"       => 'text',         "maxoccupancy"      => 'int',         "raw"               => 'int',         "nodiscountallowed" => 'int',         "defaultarrival"    => 'varchar(10)',         "defaultdeparture"  => 'varchar(10)',         "image1"            => 'varchar(255)',         "image2"            => 'varchar(255)',         "image3"            => 'varchar(255)',         "image4"            => 'varchar(255)',         "image5"            => 'varchar(255)',         "mincost"           => 'currency'     );      public static $has_many = array(         "attributes" => "attribute"     );  } 

/mymodule/models/attributes.php

class attributes extends dataobject {      private static $db = array(         "roomtypeid" => 'int', // needs correlate room.roomtypeid         "attributeid" => 'int',         "name" => 'varchar(255)'     );      private static $has_one = array(         "rooms" => "rooms"     );  } 

however docs column added db <relation-name>id not conform need correlate multiple attributes rooms.roomtypeid

due misunderstanding , time limitations i've literally been

rooms::get()->filter([...]) attributes::get()->filter([...]) 

which , on php side of things non-plausible context of template.

any guidance highly appreciated!

note: roomtypeid retrieved external api

i believe confusion may stemming treating objects full sql tables - not case. orm allow developer work in oop terms, , not have particularly worry how information stored.

i hope i'm not wrong (your description rather brief), seems you're doing too much rather particularly wrong.

each relation in silverstripe requires reverse set. not strictly required in has_one or many_many, in has_many. way silverstripe inspects model information , generates storage (cf. dev/build).

as seem particularly clued in sql, i'll jump straight technical explanations:

• $db object's native properties, not relational data.
• a has_one store external id on object's table, in form <relationship name>id, i.e. "attributes"."roomsid". generated you.
• a has_many store object's own id on relation's table. not generated you, , requires has_one on related class (as have in code demo).
• a many_many stores relations in own table, matching 2 external ids. reasonably traditional join table. reverse not strictly required because of nature of join table, idea set reverse anyway, in form belongs_many_many. let orm know relationship exists when you're dealing directly 'child' objects.

you can see above bullet points visually explained in image @ http://www.silverstrip.es/blog/diagram-of-relationships-in-silverstripe/

as side note looks you're storing image references varchars. required if information kept externally. iff images managed via silverstripe, many_many image sufficient. otherwise there examples of having many images related object in lesson 7 on official silverstripe docs website.

and furthermore, manual fetch , filter plausable template. defining function on model (or controller) rooms::getattributes() and/or attributes::getrooms() , returning get()->filter() sequence allow resulting queries accessed in template via $attributes on rooms , $rooms on attributes, respectively. should careful though, can gives issues magic fetch (via php's __call) easily.