sql - DB2 unique constraint, unique indexes and performance -

I have a table for which two lines need to be unique, they are likely to be included regularly, Perhaps these lines require an index.

I checked Infosearch on and on.

I am thinking about the difference and the performance effect both start to form an index, the unique index allows a zero value. What are the other important differences?

Do these indexed queries improve performance or are they just applying specificity? Should I add an additional index for performance reasons or what unique index would be great? Unfortunately, I still do not have enough test data yet to do this.

Unique barrier or unique index There is no performance difference and none will be sufficient during query processing DB2 The adapter will automatically raise the index created to maintain unique barrier.