When you set up index
awareness in Designer you tell Designer which database columns are primary
and foreign keys. This can have a dramatic effect on query performance in the
following ways:
• Designer can take advantage of the indexes on key columns to speed data
retrieval.
• Designer can generate SQL that filters in the most efficient way. This is
particularly important in a star schema database. If you build a query that
involves filtering on a value in a dimension table, Designer can apply the filter
directly on the fact table by using the dimension table foreign key. This
eliminates unnecessary and costly joins to dimension tables.
Designer does not ignore duplicates with index awareness. If two customers
have the same name, Designer will retrieve one only unless it is aware that each
customer has a separate primary key.