This content has been marked as final. Show 2 replies
Unique or Primary Key cannot enforce Uniqueness of a column with out a Index on that column. Hence Oracle will create an Index by default if an index does not exist on that column while createing these two constraints. So an index is always associated with these two constraints.
But a foreign key does not enforces uniqueness on a column. And an Index on a foreign key is not mandatory. So even if you create an index on a foreign key column that index is not associated with the foreign key.