Cluster Index Plays an Important Role in Database Query
Zongwei Ma · Microcomputer Development · 2000
This paper from the point of database query optimization describes that there are three basic operation involving in database query, i.e. restriction, projection, join. Different query algorithms correspond to different sequences and methods of executing these operations on the two relations involved. Four methods for a general relational query that involves the operations are compared numerically and analytically for various situations. Results indicate that an index in evaluating a query depends on whether the relation is clustered or unclustered with related to the index. [