limitless-strings-for-postgresql taken from Josh Susser's post at http://blog.hasmanythrough.com/2011/6/1/limitless-strings-for-postgresql

limitless-strings-for-postgresql

    # TODO: add integration tests. to guard against rails updates and patches
    # NOTE: http://blog.hasmanythrough.com/2011/6/1/limitless-strings-for-postgresql
    # postgres extends the SQL standard to define "character" datatype
    # without a limit.
    # as per sql-standard character needs a limit.
    # in postgres varchar is actually implemented as text with a limit
    # constraint. so varchar might be a little slower than text.
    # unlike mysql there is no performance penalty for text
    # we can use text instead of string but some rails form generators
    # will show a text-field for string and a text-area html element
    # for text,
    # from the postges manual:
    # http://www.postgresql.org/docs/8.3/static/datatype-character.html
    # Tip: There are no performance differences between these three
    # types, apart from increased storage size when using the
    # blank-padded type, and a few extra cycles to check the length
    # when storing into a length-constrained column. While
    # character(n) has performance advantages in some other database
    # systems, it has no such advantages in PostgreSQL. In most
    # situations text or character varying should be used instead.
    initializer "postgresql.no_default_string_limit" do
      ActiveSupport.on_load(:active_record) do
        if defined? ActiveRecord::ConnectionAdapters::PostgreSQLAdapter
          ActiveRecord::ConnectionAdapters::PostgreSQLAdapter::NATIVE_DATABASE_TYPES[:string].delete(:limit)
        end
      end
    end

for some form builders text would render a textbox. so we want to use a string column and a textbox but do not care for a limit to be set on the string length