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Oracle® Database Application Developer's Guide - Large Objects
10g Release 1 (10.1)

Part Number B10796-01
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This guide describes database features that support applications using Large Object (LOB) datatypes. The information in this guide applies to all platforms and does not include system-specific information.

This preface contains these topics:

Feature Coverage and Availability

Oracle Database Application Developer's Guide - Large Objects contains information that describes the features and functionality of Oracle Database 10g.

What You Need To Use LOBs

The database includes all of the resources you need to use LOBs in your application; however, there are some restrictions on how you can use LOBs as described in the following:

See Also:


Oracle Database Application Developer's Guide - Large Objects is intended for programmers developing new applications that use LOBs, as well as those who have already implemented this technology and now want to take advantage of new features.

The increasing importance of multimedia data as well as unstructured data has led to this topic being presented as an independent volume within the Oracle Application Developers documentation set.


This guide, Oracle Database Application Developer's Guide - Large Objects, is organized as follows:

Part I, "Getting Started"

This part gives introductory information and explains concepts that you must be familiar with to use LOBs in your application.

Chapter 1, "Introduction to Large Objects"

This chapter gives an introduction to LOB datatypes and describes the kinds of applications in which LOBs are useful.

Chapter 2, "Working with LOBs"

This chapter gives guidelines on working with LOB instances in your application and the database.

Chapter 3, "Managing LOBs: Database Administration"

This chapter describes database administration tasks required to setup and use databases with LOBs. Issues that application developers and database administrators must coordinate on are described.

Part II, "Application Design"

This part covers application design issues for applications that use LOBs.

Chapter 4, "LOBs in Tables"

This chapter describes how to create basic tables that contain LOB columns and gives general guidelines on selecting the best table architecture for your application.

Chapter 5, "Advanced Design Considerations"

This chapter describes more advanced application and database design issues that you may encounter when using LOBs in your application such as: buffering, caching, locators, transactions, and supersized LOBs.

Chapter 6, "Overview of Supplied LOB APIs"

This chapter gives an overview of APIs supplied with the database for using LOBs in applications.

Chapter 7, "Performance Guidelines"

This chapter discusses performance issues you should consider when designing applications that use LOBs.

Part III, "SQL Access to LOBs"

This part describes SQL usage with LOB datatypes in the SQL and PL/SQL environments.

Chapter 8, "DDL and DML Statements with LOBs"

This chapter discusses DDL and DML statements for common tasks performed on tables with LOB columns.

Chapter 9, "SQL Semantics and LOBs"

This chapter describes SQL semantics support for LOB datatypes.

Chapter 10, "PL/SQL Semantics for LOBs"

This chapter describes PL/SQL semantics support for LOB datatypes.

Chapter 11, "Migrating Table Columns from LONGs to LOBs"

This chapter describes techniques for migrating data in tables that use the LONG datatype to LOB columns.

Part IV, "Using LOB APIs"

This part gives details on LOB APIs supplied with the database.

Chapter 12, "Operations Specific to Persistent and Temporary LOBs"

This chapter describes APIs and procedures that vary depending on whether they are performed on persistent or temporary LOB instances.

Chapter 13, "Data Interface for Persistent LOBs"

This chapter describes the data interface for persistent LOBs.

Chapter 14, "LOB APIs for Basic Operations"

This chapter describes LOB APIs for operations that can be used to operate on either persistent LOB or temporary LOB instances.

Chapter 15, "LOB APIs for BFILE Operations"

This chapter describes LOB APIs that are used exclusively with BFILEs.

Appendix A, "LOB Demonstration Files"

This appendix lists and describes sample code included in this book for demonstration purposes.


Defines terms used in discussions about LOBs.

Related Documents

For more information, see the following manuals:

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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 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.


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 monospace (fixed-width font) italic

Lowercase monospace italic 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


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Accessibility of Code Examples in Documentation

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