动态子类化和ActiveRecord建立与PostgreSQL数据库的连接

Question

I'm trying to create a utility to copy a subset of records from a single table of one PostgreSQL database to that same table in another PostgreSQL database. I'm doing this with dynamic subclassing, but it's not working: it raises the error "xxx database is not configured" (where xxx is my database URL, something like "postgres://username:password@computername:5432/databasename". I know the URL is good because I copied it from my Heroku configuration and I am able to access the database from pgAdmin3 on my local machine. Here's the code:

puts "Enter the database URL"
url = gets.chomp
db_conn = Class.new(ActiveRecord::Base) do
  establish_connection url
end

Answer 1

Support for establish_connection(url) was added in Rails 3.2; I was running Rails 3.1.3.