Usage of external DB objects- table/query (not Documentum object)

External DB objects - table/query (not Documentum object) is accessable only for Super User permission user. In general you get it, when query to DB by docbase owner alias dm_dbo (select * from  dm_dmo.table_name).

For using an object in external DB - this object should be registered.

1) Execute query "register"

REGISTER TABLE DOCUM.OBJECT_NAME (ANYFIELD CHAR(8))

/* where DOCUM - docbase owner
              OBJECT_NAME - table/query
*/

2) Grant permission for users. Execute query "update"

update dm_registered object 

set owner_table_permit=15
set group_table_permit=15
set world_table_permit=15

where object_name ='OBJECT_NAME '

A great artice about Registered Tables you may find by the link
http://www.bluefishgroup.com/1999/documentum-registered-tables/