DataMapper- can I avoid intermediate tables? -


i total beginner @ datamapper, , have 2 models:

class thirdpartyaccount     include datamapper::resource     property :access_token,     string, :length => 500     belongs_to :user end  class user     include datamapper::resource     property :id,           serial     property :first_name,    string     has n, :third_party_accounts, :through => resource end

looking @ sql logs, appears create 2 tables- users, third_party_accounts , third_party_account_users join two. doesn't appear last table needed- surely third_party_account table needs use it's user_id field map directly user table? have accidentally created many-to-many relationship here?

it's due line:

has n, :third_party_accounts, :through => resource

:through => resource tells datamapper it's "has-and-belongs-to-many" relation (each 3rd party account belongs multiple users , each user has multiple 3rd party accounts), requires intermediate table. if has-many relation (each user has many 3rd party accounts, each account belongs 1 user), should use:

class user   ...   has n, :third_party_accounts end

see http://datamapper.org/docs/associations.html more info.


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