A query optimiser needs to know the storage structures used for tables. Some of the
commonly used storage structures are outlined here. We assume that tables are stored
on direct access devices such as disk drives. The discussion refers to the Student table
shown in Fig. 18.1. As this sample table contains only a few rows and columns, it could
be held entirely in main memory and searched by a simple linear scan of the rows. It is
used here to illustrate techniques that are used to access the much larger tables likely to
be encountered in reality. It is worth bearing in mind, though, that one of the most
effective ways of improving ...
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