Hello,
You cannot disable indexes. They can be dropped or made unusable. I am sure you are referring to contraints.
Here is how you find out the name of the index on table EMP:
SQL> select index_name,uniqueness from dba_indexes where table_name='EMP';
INDEX_NAME UNIQUENES
------------------------------ ---------
EMP_ID_IX NONUNIQUE
SQL> select constraint_name,index_name, constraint_type from dba_constraints
where table_name='EMP' and constraint_type='P';
CONSTRAINT_NAME INDEX_NAME C
------------------------------ ------------------------- -
PK_EMP_ID EMP_ID_IX P
You can then disable the constraint as follows:
SQL> alter table scott.emp DISABLE constraint pk_emp_id;
You can also drop an index using
SQL> drop index <index_name>;
Regards.
Shahid.