ORA-12985 Tablespace Users is Read Only, Cannot Drop Column in Oracle Database

The Object which is trying to drop belongs to a table sapce is in read only mode

Step 1 : Find the tablespace of that particular table

SQL> select tablespace_name from dba_segments where segment_name='MASTER03';
 
TABLESPACE_NAME
------------------------------
USERS

Step 2 : Find the staus of the tablespace

SQL> select tablespace_name,status from dba_tablespaces where tablespace_name='USERS';

TABLESPACE_NAME                STATUS
------------------------------ --------------------
USERS                            READ ONLY

Step 3: Inorder to Drop a column ,We need to make the tablespace READ and WRITE mode only

SQL> ALTER TABLESPACE users READ WRITE;

 Tablespace altered.

SQL> select tablespace_name,status from dba_tablespaces where tablespace_name='USERS';

TABLESPACE_NAME                STATUS
------------------------------ ------------------
USERS                             ONLINE

SQL> alter table chaitanyadba.master03 drop (OWNER,OBJECT_NAME);

Table altered.