This preface contains these topics:

Intended Audience

This guide is intended for database administrators, system administrators, and database application developers who design, maintain, and use data warehouses.

To use this document, you need to be familiar with relational database concepts, basic Oracle server concepts, and the operating system environment under which you are running Oracle.

Documentation Accessibility

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Accessibility of Code Examples in Documentation

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This document contains:

Part 1: Concepts

Chapter 1, "Data Warehousing Concepts"

This chapter contains an overview of data warehousing concepts.

Part 2: Logical Design

Chapter 2, "Logical Design in Data Warehouses"

This chapter discusses the logical design of a data warehouse.

Part 3: Physical Design

Chapter 3, "Physical Design in Data Warehouses"

This chapter discusses the physical design of a data warehouse.

Chapter 4, "Hardware and I/O Considerations in Data Warehouses"

This chapter describes hardware, input-output, and storage considerations.

Chapter 5, "Partitioning in Data Warehouses"

This chapter describes the basics of partitioning in data warehouses.

Chapter 6, "Indexes"

This chapter describes how to use indexes in data warehouses.

Chapter 7, "Integrity Constraints"

This chapter describes how to use integrity constraints in data warehouses.

Chapter 8, "Basic Materialized Views"

This chapter introduces basic materialized views concepts.

Chapter 9, "Advanced Materialized Views"

This chapter describes how to use materialized views in data warehouses.

Chapter 10, "Dimensions"

This chapter describes how to use dimensions in data warehouses.

Part 4: Managing the Data Warehouse Environment

Chapter 11, "Overview of Extraction, Transformation, and Loading"

This chapter is an overview of the ETL process.

Chapter 12, "Extraction in Data Warehouses"

This chapter describes extraction issues.

Chapter 13, "Transportation in Data Warehouses"

This chapter describes transporting data in data warehouses.

Chapter 14, "Loading and Transformation"

This chapter describes transforming and loading data in data warehouses.

Chapter 15, "Maintaining the Data Warehouse"

This chapter describes how to refresh a data warehouse.

Chapter 16, "Change Data Capture"

This chapter describes how to use Change Data Capture capabilities.

Part 5: Data Warehouse Performance

Chapter 17, "Basic Query Rewrite"

This chapter describes basic query rewrite use.

Chapter 18, "Advanced Query Rewrite"

This chapter describes how to use query rewrite in more complex situations.

Chapter 19, "Schema Modeling Techniques"

This chapter describes the schemas useful in data warehousing environments.

Chapter 20, "SQL for Aggregation in Data Warehouses"

This chapter explains how to use SQL aggregation in data warehouses.

Chapter 21, "SQL for Analysis and Reporting"

This chapter explains how to use analytic functions in data warehouses.

Chapter 22, "SQL for Modeling"

This chapter explains how to use the spreadsheet clause for SQL modeling.

Chapter 23, "OLAP and Data Mining"

This chapter describes using analytic services and data mining in combination with Oracle Database.

Chapter 24, "Advanced Business Intelligence Queries"

This chapter illustrates examples of combining business intelligence techniques.

Chapter 25, "Using Parallel Execution"

This chapter describes how to tune data warehouses using parallel execution.


The glossary defines important terms used in this guide.

Related Documentation

Many of the examples in this book use the sample schemas of the seed database, which is installed by default when you install Oracle. Refer to Oracle Database Sample Schemas for information on how these schemas were created and how you can use them yourself.

Printed documentation is available for sale in the Oracle Store at

To download free release notes, installation documentation, white papers, or other collateral, please visit the Oracle Technology Network (OTN). You must register online before using OTN; registration is free and can be done at

If you already have a username and password for OTN, then you can go directly to the documentation section of the OTN Web site at

Note that this book is meant as a supplement to standard texts about data warehousing. This book focuses on Oracle-specific material and does not reproduce in detail material of a general nature. For additional information, see:


This section describes the conventions used in the text and code examples of this documentation set. It describes:

Conventions in Text

We use various conventions in text to help you more quickly identify special terms. The following table describes those conventions and provides examples of their use.

Convention Meaning Example
Bold Bold typeface indicates terms that are defined in the text or terms that appear in a glossary, or both. When you specify this clause, you create an index-organized table.
Italics Italic typeface indicates book titles or emphasis. Oracle Database Concepts

Ensure that the recovery catalog and target database do not reside on the same disk.

UPPERCASE monospace (fixed-width) font Uppercase monospace typeface indicates elements supplied by the system. Such elements include parameters, privileges, datatypes, RMAN keywords, SQL keywords, SQL*Plus or utility commands, packages and methods, as well as system-supplied column names, database objects and structures, usernames, and roles. You can specify this clause only for a NUMBER column.

You can back up the database by using the BACKUP command.

Query the TABLE_NAME column in the USER_TABLES data dictionary view.


lowercase monospace (fixed-width) font Lowercase monospace typeface indicates executables, filenames, directory names, and sample user-supplied elements. Such elements include computer and database names, net service names, and connect identifiers, as well as user-supplied database objects and structures, column names, packages and classes, usernames and roles, program units, and parameter values.

Note: Some programmatic elements use a mixture of UPPERCASE and lowercase. Enter these elements as shown.

Enter sqlplus to open SQL*Plus.

The password is specified in the orapwd file.

Back up the datafiles and control files in the /disk1/oracle/dbs directory.

The department_id, department_name, and location_id columns are in the hr.departments table.

Set the QUERY_REWRITE_ENABLED initialization parameter to TRUE.

Connect as oe user.

The JRepUtil class implements these methods.

lowercase italic monospace (fixed-width) font Lowercase italic monospace font represents placeholders or variables. You can specify the parallel_clause.

Run Uold_release.SQL where old_release refers to the release you installed prior to upgrading.

Conventions in Code Examples

Code examples illustrate SQL, PL/SQL, SQL*Plus, or other command-line statements. They are displayed in a monospace (fixed-width) font and separated from normal text as shown in this example:

SELECT username FROM dba_users WHERE username = 'MIGRATE';

The following table describes typographic conventions used in code examples and provides examples of their use.

Convention Meaning Example
[ ]
Brackets enclose one or more optional items. Do not enter the brackets.
DECIMAL (digits [ , precision ])
{ }
Braces enclose two or more items, one of which is required. Do not enter the braces.
A vertical bar represents a choice of two or more options within brackets or braces. Enter one of the options. Do not enter the vertical bar.
Horizontal ellipsis points indicate either:
  • That we have omitted parts of the code that are not directly related to the example

  • That you can repeat a portion of the code

CREATE TABLE ... AS subquery;

SELECT col1, col2, ... , coln FROM employees;
Vertical ellipsis points indicate that we have omitted several lines of code not directly related to the example.
9 rows selected.
Other notation You must enter symbols other than brackets, braces, vertical bars, and ellipsis points as shown.
acctbal NUMBER(11,2);
acct    CONSTANT NUMBER(4) := 3;
Italicized text indicates placeholders or variables for which you must supply particular values.
CONNECT SYSTEM/system_password
DB_NAME = database_name
Uppercase typeface indicates elements supplied by the system. We show these terms in uppercase in order to distinguish them from terms you define. Unless terms appear in brackets, enter them in the order and with the spelling shown. However, because these terms are not case sensitive, you can enter them in lowercase.
SELECT last_name, employee_id FROM employees;
DROP TABLE hr.employees;
Lowercase typeface indicates programmatic elements that you supply. For example, lowercase indicates names of tables, columns, or files.

Note: Some programmatic elements use a mixture of UPPERCASE and lowercase. Enter these elements as shown.

SELECT last_name, employee_id FROM employees;
sqlplus hr/hr