Make Rails 3.0.11 support PostgreSQL temporary tables

active_record_initializer.rb

class ActiveRecord::ConnectionAdapters::PostgreSQLAdapter 
  
  def table_exists?(name)
    name          = name.to_s
    schema, table = name.split('.', 2)

    unless table 
      table  = schema
      schema = nil
    end

    if name =~ /^"/ # Handle quoted table names
      table  = name
      schema = nil
    end

    schema_clause = schema ? "n.nspname = '#{schema}'" 
                           : "( n.nspname = ANY (current_schemas(false)) OR n.oid = pg_my_temp_schema() )"

    query(<<-SQL).first[0].to_i > 0
      SELECT COUNT(*)
      FROM pg_class c
      LEFT JOIN pg_namespace n ON n.oid = c.relnamespace
      WHERE c.relkind in ('v','r')
      AND c.relname = '#{table.gsub(/(^"|"$)/,'')}'
      AND #{schema_clause}
    SQL
  end

end