SQL: How to tell if an existing index is unique?

A. Oracle

select INDEX_NAME, UNIQUENESS
from dba_indexes
where owner ='<owner>' and INDEX_NAME = '<index name>';

      Sample output:

INDEX_NAME                     UNIQUENES
------------------------------       ---------
EMPLOYEE_KEY_IDX      UNIQUE

B. Postgresql

SELECT relname AS INDEX_NAME, indisunique as UNIQUENESS
FROM pg_class, pg_index
WHERE pg_class.oid = pg_index.indexrelid AND relname !~ '^pg_' and relname = '<index name>';

        Sample output:

           index_name                             uniqueness
------------------------------------------+------------
 employee_license_idx                      f

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