Preface

The Oracle Database Ap plication Developer's Guide - Fundamentals describes basic application development features of Oracle Database 10g. Information in this guide applies to features that work the same on all supported platforms, and does not include sy stem-specific information.

This preface contains these topics:

Audience

Oracle Database Application Developer's Guide - Fundamentals is intended for programmers developing new applications or converting existing applications to run in the Oracle Database environment. This book will also be valuable to systems analysts, proj ect managers, and others interested in the development of database applications.

This guide assumes that you have a working knowledge of application programming, and that you are familiar with the use of Structured Query Lang uage (SQL) to access information in relational database systems.

Certain sections of this gu ide also assume a knowledge of the basic concepts of object-oriented programming.

Duties of an Application Developer

Activities that are typically required of an application developer include:

Pr ogramming in SQL. Your primary source of information for this is the Oracle Database SQL Reference. In the Oracle Data Warehousing Guide,you can find information about advanced query techniques, to perform analysis and retrieve data in a single query,
Interfacing to SQL through other languag es, such as PL/SQL, Java, or C/C++. Sources of information about these other languages include:
Setting up interactions and mappin gs between multiple language environments, as described in "Calling External Procedures".
Working with schema objects. You might design part o r all of a schema, and write code to fit into an existing schema. You can get full details in Oracle Database Administrator's Guide.
Interfacing with the database administrator to make sure that the schema can be backed up and restored, for example aft er a system failure or when moving between a staging machine and a production machine.
Building application logic into the database itself, in the form of stored procedures, constraints, and triggers, to allow mu ltiple applications to reuse application logic and code that checks and cleans up errors. For information on these database features, see "Using Procedures and Packages", "Maintaining Data Integrity Through Constraints", and "Us ing Triggers".
Some degree of performanc e tuning. The database administrator might help here. You can find more information in PL/SQL User's Guide and Reference, PL/SQL Packages and Types Reference, and Oracle Database Performance Tuning Guide.
Some amount of database administration, if you need to maintain your own development or test sy stem. You can learn about administration in the O racle Database Administrator's Guide.
Debugging and interpreting error messages. See "Related Documentation".
Making your application available over the network, particularly over the Internet or company intranet. Yo u can get an overview in "Developing Web Applications with PL/SQL"< /a>, and full details covering various languages and technologies in the Oracle Application Server documentation.

Designing the class structure and choosing object-oriented methodologies, if your application is o bject-oriented. For more information, see Oracle Database Application Developer's Guide - Object-Relational Features, PL/SQL User's Guide and Reference, and Oracle Database Java Developer's Guide.

Organization

This document contains:

Part I: Introduction

This part introduces several ways that you can write Oracle Database applications. You might need to use more than one language or development environment for a single application. Some database features are only supported by, or are easier to access from, certain languages.

Chapter 1, "Programmatic Environments"

This chapter outline s the strengths of the languages, development environments, and APIs that Oracle Database provides.

Part II: Designing the Database

Before you develop an application, you need to plan the characteristics of the associated database. You must choose all the pieces th at go into the database, and how they are put together. Good database design helps ensure good performance and scalability, and reduc es the amount of application logic you code by making the database responsible for things like error checking and fast data access.

Chapter 2, "S electing a Datatype"

This chapter explains how to represent your business data i n the database. The datatypes include fixed- and variable-length character strings, numeric data, dates, raw binary data, and row ide ntifiers (ROWIDs).

Chapter 3, "Maintaining Data Integrity Through Constraints"

This chapter explains how to use constraints to move error-checking logic out of your application and into the database.

Chapter 4, "Selecting an Index Strategy"

This chapter explains how to choose the best indexing strategy for your application.

Chapter 5, "How Oracle Database Processes SQL Statements"

This chapter explains SQL topics such as commits, cursors, and locking that you can take advantage of in your applications.

Chapter 6, "Coding Dynamic SQL St atements"

This chapter describes dynamic SQL, compares native dynamic SQL to the DBMS_SQL package, and explains when to use dynamic SQL.

Chapter 7, "Using Procedures and Packages"

This chapter explains how to store reusable procedures in the database, and how to group procedures into packages.

Chapter 8, "Calling Ex ternal Procedures"

This chapter explains how to code the bodies of computation i ntensive procedures in languages other than PL/SQL.

Part III: The Active Database

You can include all sorts of programming logic in the database itself, making the benefits available to many applications and saving repetitious coding work.

Chapter 9, "Using Triggers"

This chapter explains how to make the database do special processing before, after, or in stead of running SQL statements. You can use triggers for things like logging database access and validating or transforming data.

Chapter 10, "W orking With System Events"

This chapter explains how to retrieve information, su ch as the user ID and database name, about the event that fires a trigger.

Chapter 11, "Using the Publish-Subscribe Model for Applications"

This chapter introduces the Oracle Database model for asynchronous communication, als o known as messaging or queuing.

Part IV: Develo ping Specialized Applications

Chapter 12, "Using Regular Expressions With Oracle Database"

This chapter discusses regular expression support built into Oracle Database, regular expression syntax, and how to write quer ies using regular expressions in SQL.

Chapter 13, "Developing Web Applications with PL/SQL"

This chapter explains how to create dynamic Web pages and applications that work with the Internet, e-mail, and so on, using the PL/S QL language.

Chap ter 14, "Porting Non-Oracle Applications to Oracle Database 10g"

Thi s chapter lists features and techniques you can use to make applications run on Oracle Database 10g that were originally written for another, non-Oracle database.

Chapter 15, "Using Flashback Features"

This chapter describes how to use features that let you examine past data and its history, and to recover that data.

Chapter 16, "Using Ora cle XA with Transaction Monitors"

This chapter describes how to connect Oracle D atabase with a transaction monitor.

Related Docum entation

For more information, see these Oracle resources.

Use the PL/SQL User's Guide and Reference to learn PL/SQL and to get a complete description of the PL/SQL high-level programming language, which is Oracle's procedural extension to SQL.
The Oracle Call Inter face (OCI) is described in Oracle Call Interface Programmer's Guide and Oracle C++ Call I nterface Programmer's Guide.

You can use the OCI to build third-generation lang uage (3GL) applications that access the Oracle Database.
The Oracle Database Security Guide d iscusses security features of the database that application developers and database administrators need to be aware of.
Oracle also provides the Pro* series of precompilers, which allow you to embed SQL and PL/SQ L in your application programs. If you write 3GL application programs in C, C++, COBOL, or FORTRAN that incorporate embedded SQL, the n refer to the corresponding precompiler manual. For example, if you program in C or C++, then refer to the Pro*C/C++ Programmer's Guide.
Oracle Developer/2000 is a cooperative development environment that provides several tools including a form builde r, reporting tools, and a debugging environment for PL/SQL. Refer to the appropriate Oracle Developer/2000 documentation if you use t his product.
For SQL information, see the Oracle Database SQL Reference and Oracle Database Administrator's Guide. For basic Oracle Database concepts, see Oracle Database Concepts.
For developing applications that manipulate XML data, see Oracle XML Developer's Kit Programmer's Guide and Oracle XML DB Developer's Guide.
Oracle Database error message documentation is available only in HTML. If you have access only to the Oracle Docume ntation CD, you can browse the error messages by range. After you find the specific range, use your browser's "find in page" feature to locate the specific message. When connected to the Internet, you can search for a specific error message using the error message s earch feature of the Oracle Database online 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 docum entation is available for sale in the Oracle Store at
```
http://oraclestore.oracle.com/
```
To download f ree release notes, installation documentation, white papers, or other collateral, visit the Oracle Technology Network (OTN). You must register online before using OTN; registration is free and can be done at
```
http://otn.oracle.com/membership/
```
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

http://otn.oracle.com/documentation/

Conventions

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

Conventions in Text
Conventions in Code Examples

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 te xt or terms that appear in a glossary, or both.	When you specify t his clause, you create an index-organized table.
Italics	Italic typeface indicates book titles or emphasis.	Oracle Database Concepts Ensure that the recovery ca talog 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 e lements include parameters, privileges, datatypes, RMAN keywords, SQL keywords, SQL*Plus or utility commands, packages and methods, a s 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 `TAB LE_NAME` column in the `USER_TABLES` data dictionary view. Use the `DBM S_STATS`.`GENERATE_STATS` procedure.
`lowercase monospace (fixed-width) font`	Lowercase monospace typeface indicates executable, filenames, directory names, and sample user-supplied el ements. Such elements include computer and database names, net service names, and connect identifiers, as well as user-supplied datab ase 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. < p class="TB">The `department_id`, `department_name`, and `location_id` columns are in the `hr.d epartments` 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 `U``old_release``.SQL` where `old_release` refer s to the release you installed prior to upgrading.

Conventions in Code Examples

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

SELECT username FROM dba_users WHERE username = 'MIGRATE'
;

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

lowercase

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 b races.	`{ENABLE \| DISABLE}`
\|	A vertical bar represents a choice of two or more options within brackets or braces. Enter one of the op tions. Do not enter the vertical bar.	`{ENABLE \| DISABLE}` `[COMPRESS \| NOCOMPRESS]`
`...`	< /a> 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 h ave omitted several lines of code not directly related to the example.
Other notation	You must enter symbols other than brackets, braces, vertical bars, and e llipsis points as shown.	acctbal NUMBER(11,2); acct CONSTANT NUMBER(4) := 3;
`Italics`	Italicize d text indicates placeholders or variables for which you must supply particular values.	`CONNECT SYSTEM/``system_password` `DB_NAME =` `database_name`
`UPPERCASE`	Up percase 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 no t case sensitive, you can enter them in lowercase.	`SELECT la st_name, employee_id FROM employees;` `SELECT * FROM USER_TABLES;` `DROP TABLE hr.employees;`
< p class="TB">Lowercase typeface indicates programmatic elements that you supply. For example, lowercase indicates names of tables, co lumns, 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` `CREATE USER mjones IDENTIFIED BY ty3MU9;`

Documentation Accessibility

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Accessibility of Code E xamples in Documentation

JAWS, a Windows screen reader, may not always correctly rea d the code examples in this document. The conventions for writing code require that closing braces should appear on an otherwise empt y line; however, JAWS may not always read a line of text that consists solely of a bracket or brace.

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