1.最近每次执行rake db:migrate时总是提示出现错误,如下所示,为什么呀???
[code="ruby"]== CreateFriendships: migrating ==============================================
-- create_table(:friendships)
-> 0.2310s
-- add_index(:friendships, [:user_id, :friend_id])
-> 0.1990s
== CreateFriendships: migrated (0.4320s) =====================================
rake aborted!
Don't know how to build task 'CreateFriendships'
(See full trace by running task with --trace)[/code]
2.一个关于ActiveRecord的问题:
[code="ruby"]
@user = User.find(params[:user_id],:include=>[:friendships=>:friend])
[/code]
中的
[code="ruby"]
:include=>[:friendships=>:friend]
[/code]
是什么意思?