Physical Database Design

82 CHAPTER 5 Selecting Materialized Views

Again, we see a savings in disk I/O resulting from utilizing a materialized view to

answer repeated queries. At this point, one might think, “I’ll just keep going, and create

a materialized view for each of the common queries and make a huge net gain!” How-

ever, we do need to live within our resource constraints. There are a number of con-

straints discussed in Section 5.4. Suffice it to say here, we need to keep the number of

materialized views under control. Let’s examine the possibility of combining some

materialized views.

If you’ll look back at Figures 5.2, 5.3, and 5.4, you’ll notice that they all have cost,

sell, and profit in common. It is reasonable to consider combining these tables, since

they are ...