Reference to forum: http://drupal.org/node/1272132
When using Postgres (tested on 9.1.8) the system update hook 7016 does not correctly change the field types. The following trace is taken from the forum post.
Failed: PDOException:
SQLSTATE[2BP01]: Dependent objects still exist: 7
ERROR: cannot drop type smallint_unsigned because other objects depend on it
DETAIL:
default for table comment column status depends on type smallint_unsigned
default for table node_access column grant_view depends on type smallint_unsigned
default for table node_access column grant_update depends on type smallint_unsigned
default for table node_access column grant_delete depends on type smallint_unsigned
default for table taxonomy_vocabulary column relations depends on type smallint_unsigned
default for table taxonomy_vocabulary column hierarchy depends on type smallint_unsigned
default for table taxonomy_vocabulary column multiple depends on type smallint_unsigned
default for table taxonomy_vocabulary column required depends on type smallint_unsigned
default for table taxonomy_vocabulary column tags depends on type smallint_unsigned
default for table watchdog column severity depends on type smallint_unsigned
HINT: Use DROP ... CASCADE to drop the dependent objects too.:
DROP DOMAIN IF EXISTS smallint_unsigned;
Array ( ) in system_update_7016()
(line 2058 of /home/appadmin/solarheadlines.com/html/modules/system/system.install).This bug is because the default value of each column is not updated with the column's type.