15.00 - Materialized Join Index - Teradata Database

Teradata Database Design

prodname
Teradata Database
vrm_release
15.00
category
User Guide
featnum
B035-1094-015K

Materialized Join Index

The resulting join index rows would be the following (where the ? character indicates a null).

 

With the join index defined in this way, the following query could be resolved using just the join index, without having to scan the base tables.

     SELECT o_status, o_date, o_comment
     FROM orders;

In this particular case, it is more efficient to access the join index than it is to access the orders base table. This is true whenever the cost of scanning the join index is less than the cost of scanning the orders table. The Optimizer evaluates both access methods, choosing the more efficient, less costly of the two for its query plan.