Module /DB/Pg.pm
TODO list:
  1. get_sequence_info
 Functionality list:
  1. make_dsn
  2. get_databases
  3. get_tables
  4. get_views
  5. get_indexes
  6. get_sequences
  7. get_table_info
  8. get_view_info
  9. get_index_info
  10. delete_table
  11. delete_view
  12. delete_index
  13. delete_sequence