I just came across an obscure little bug in AR - I ran something like this:

SomeModel.count(:group => 'foofoofoofoo, barbarbarbar, bazbazbazbaz')

which generates a (unnecessary) column alias longer than the 30 characters allowed by Oracle:

SELECT 1 AS foofoofoofoo_barbarbarbar_bazbazbazbaz FROM dual;
ORA-00972: identifier is too long

This seems to have been addressed to some extent between AR2.1.2 (where I'm stuck at present) and 2.3.4, which has

module ActiveRecord
module ConnectionAdapters # :nodoc:

module SchemaStatements
  # Returns a Hash of mappings from the abstract data types to the native
  # database types.  See TableDefinition#column for details on the recognized
  # abstract data types.
  def native_database_types
    {}
  end

  # This is the maximum length a table alias can be
  def table_alias_length
    255
  end

  # Truncates a table alias according to the limits of the current adapter.
  def table_alias_for(table_name)
    table_name[0..table_alias_length-1].gsub(/\./, '_')
  end

For Oracle, we need table_alias_length to return 30.

Not that I can actually use it, of course (I had to hack calculations.rb, grrr) but it would be nice to see it in the adapter if I ever get to update...