Using a Function as an Index Key (IDS)

A functional index is indexed on the value that the specified function returns, rather than on the value of a column. For example, the following statement creates a functional index on table zones using the value that the function Area( ) returns as the key:

CREATE INDEX zone_func_ind ON zones (Area(length,width));

You can create functional indexes within an SPL routine. You can also create an index on a nonvariant user-defined function that does not return a large object. The functional index can be a B-tree index, an R-tree index, or a user-defined secondary-access method. The ONLINE keyword, however, is not valid when you create a functional index; see The ONLINE Keyword (IDS).