How to tell in what indices a particular field participates

Question

I have a table with a field where I suspect the values are not unique when in fact they should be. I want an easy way to tell if the values are unique. Is there an easy way to do this?
I tried creating a unique index on the table. But the schema manager tells me that such fields are already indexed. The index names on the database are quite critic and hardly gives a clue as to what fields participates in them. Is there a way to tell in what indeices a particular participates/resides?

Answer 1

Another way you can find duplicates is to us the script utlexcpt.sql found in $ORACLE_HOME/rdbms/admin. That script will create an exceptions table. To find duplicates just add a unique constraint to the table you are checking using the following syntax:
alter table <table_name> add constraint <constraint_name>
unique(<column_or_columns_list>)
exceptions into exceptions.
When the constraint fails, the rowids of the duplicate rows will be placed into the exceptions table. Care should be taken here. If you have two duplicate rows in the table, the exceptions table will have the rowids of both rows.