Hi friends,
I need to create an unique index on a set of 6 fields, which combinedly make a record as unique in one of our tables(there is no single field which is unique on its own).
I need to know, how does Oracle work when it creates the index or when validating the uniqueness. For example, let us say the index is on col1 to col6, in that order. Col1 has values which have the maximum chance to be unique and col6 has least chances. So, if a new record is inserted which has an unique value of col1, are the other columns still compared or not?
The main point here is that I need to select the order of the columns in the index. What will be the best order : "most unique chances" to "least unique chances" or it does not matter?
Thanks
manjunath