legacy database and rails with its auto incrementing primary key problems

rubyonrails-talk
1

I'm sorta stuck as to what to do. I'm porting a legacy database where the primary key were not auto incrementing fields.

An example

create_table: components do |t|   t.integer :componentid   ... end

and

create_table: versions do |t|   t.integer :versionid   t.integer :componentid   ... end

The foreign key for table versions is componentid from table components. In MySQL, the primary key would be 'id', an auto incrementing field. I would have liked to make componentid in components my primary key but seems rails does not like non-auto incrementing primary keys...so the question becomes how do I create the key relationship? I would like to be make searches along the lines of version=components.versions.versionid or some such. Am I making any sense?

Thanks in advance, Hubert