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• Table of Contents• Index• Reviews• Examples• Reader Reviews• Errata• AcademicSQL TuningBy
Publisher: OReillyPub Date: November 2003ISBN: 0-596-00573-3Pages: 336
SQL Tuning author Dan Tow outlines a
timesaving method hes developed for finding the optimum
execution plan--rapidly and systematically--regardless of
the complexity of the SQL or the database platform being
used. Youll learn how to understand and control SQL
execution plans and how to diagram SQL queries to deduce the
best execution plan for a query. Key chapters in the book
includes exercises to reinforce the concepts youve learned.
SQL Tuning concludes by addressing
special concerns and unique solutions to "unsolvable"
problems.
B.4 Altering the Database to Enable the Best Plan
The earlier results on DB2 and SQL
Server have already demonstrated that the database design has the
necessary indexes to enable the execution plan that you need, unless
the Oracle database is missing indexes that you have on the other
databases. Therefore, you could skip this step. However, if you did
not already know that they existed, you would check for indexes on
Customers(Phone_Number),
Orders(Customer_ID), and
Order_Details(Order_ID) using the methods of Chapter 3. You can generally take for granted that the
primary-key indexes that you need already exist. Look for missing
primary-key indexes only when more likely reasons for an incorrect
execution plan do not solve the problem and lead you to check for
unusual sources of trouble.
