-- SYSTEM_IDX is new tablespace
ALTER INDEX ADMIN.UNIQUE_ITEM REBUILD TABLESPACE SYSTEM_IDX;

tablesize

add tablespace

ALTER TABLESPACE AUDIT_space
  ADD DATAFILE '/u01/database/DB1/oradata/DB1_audit.dbf'
  SIZE 1G
  AUTOEXTEND OFF;

view tablespace of user

SELECT DISTINCT sgm.TABLESPACE_NAME , dtf.FILE_NAME
FROM DBA_SEGMENTS sgm
JOIN DBA_DATA_FILES dtf ON (sgm.TABLESPACE_NAME = dtf.TABLESPACE_NAME)
WHERE sgm.OWNER = 'ADMIN'