Multiple Index Access - Relational Database Index Design and the Optimizers - page 193

Chapter 10

Multiple Index Access

ž Index ANDing
ž Pitfalls and comparison with the use of a single index
ž Use with query tables and fact tables
ž Bitmap indexes
ž Index ORing
ž Boolean predicates
ž Comparison with the use of a single index
ž SQL Server index joins.

INTRODUCTION

Many DBMSs are able to collect pointers from several indexes on a table, or
indeed from several slices of a single index, compare these sets of pointers and
then access the rows that satisfy all the predicates in a WHERE clause. This
capability is called multiple index access or index ANDing (index intersection )
and index ORing (index union ). In this chapter we will consider when these
features are useful and how they affect index design.

INDEX AND ING

SQL 10.1

SELECT B, C

FROM TX

WHERE A = :A

AND
B BETWEEN :B1 AND :B2

ORDER BY B