Rails custom foreign key not respected -

the relevant database tables have these schemas:

sqlite> .schema structures create table structures(         struct_id integer primary key autoincrement not null,         batch_id integer,         tag text,         input_tag text,         foreign key (batch_id) references batches(batch_id) deferrable deferred); sqlite> .schema residues create table residues(         struct_id integer not null,         resnum integer not null,         name3 text not null,         res_type text not null,         foreign key (struct_id) references structures(struct_id) deferrable deferred,         primary key (struct_id, resnum)); 

i have following models:

class structure < activerecord::base     set_table_name "structures"     self.primary_key = "struct_id"      attr_accessible :struct_id, :batch_id, :input_tag      has_many :residues end  class residue < activerecord::base   self.primary_keys :struct_id, :resnum   belongs_to :structure, :foreign_key => 'struct_id'   attr_accessible :name3, :res_type, :resnum end 

in structures show have:

<h2>residues</h2> <% @structure.residues.each |residue| %>   <p>     <b>residue number:</b>     <%= residue.resnum %>   </p>    <p>     <b>residue type:</b>     <%= residue.res_type %>   </p> <% end %> 

however, when try show structure following error:

sqlite3::sqlexception: no such column: residues.structure_id 

why structure_id being looked in database , not struct_id? seems foreign key not being respected.

you need specify foreign key on both sides of relationship ( has_many , belongs_to)