Local Prefixed Indexes
A local index is prefixed if it is partitioned on a left prefix of the index columns and the subpartioning key is included in the index key. Local prefixed indexes can be unique or nonunique.
For example, if the sales table and its local index sales_ix are partitioned on the week_num column, then index sales_ix is local prefixed if it is defined on the columns (week_num, xaction_num). On the other hand, if index sales_ix is defined on column product_num then it is not prefixed.
Figure 3-4 illustrates another example of a local prefixed index.
