Book Image

Advanced Oracle PL/SQL Developer's Guide (Second Edition) - Second Edition

By : Saurabh K. Gupta
Book Image

Advanced Oracle PL/SQL Developer's Guide (Second Edition) - Second Edition

By: Saurabh K. Gupta

Overview of this book

Oracle Database is one of the most popular databases and allows users to make efficient use of their resources and to enhance service levels while reducing the IT costs incurred. Oracle Database is sometimes compared with Microsoft SQL Server, however, Oracle Database clearly supersedes SQL server in terms of high availability and addressing planned and unplanned downtime. Oracle PL/SQL provides a rich platform for application developers to code and build scalable database applications and introduces multiple new features and enhancements to improve development experience. Advanced Oracle PL/SQL Developer's Guide, Second Edition is a handy technical reference for seasoned professionals in the database development space. This book starts with a refresher of fundamental concepts of PL/SQL, such as anonymous block, subprograms, and exceptions, and prepares you for the upcoming advanced concepts. The next chapter introduces you to the new features of Oracle Database 12c, not limited to PL/SQL. In this chapter, you will understand some of the most talked about features such as Multitenant and Database In-Memory. Moving forward, each chapter introduces advanced concepts with the help of demonstrations, and provides you with the latest update from Oracle Database 12c context. This helps you to visualize the pre- and post-applications of a feature over the database releases. By the end of this book, you will have become an expert in PL/SQL programming and will be able to implement advanced concepts of PL/SQL for efficient management of Oracle Database.
Table of Contents (19 chapters)
Advanced Oracle PL/SQL Developer's Guide Second Edition
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Subtypes


A subtype is a data type that gets evolved from an existing scalar data type. The purpose of creating subtypes, though not mandatory, is to customize the primary data types by controlling certain features such as nullability, range, or sign. An unconstrained subtype is often used in place of primary data types to maintain application standards.

The subtype inherits the behavior of its parent base type and extends it further by a distinguishing feature. For example, NATURALN is a subtype of BINARY_INTEGER, which prevents the entry of nulls and negative values. Similarly, SIGNTYPE permits only three fixed values: -1, 0, or 1.

The following table shows the base types and subtypes under each scalar data type:

Number

Character

Date/Time

Boolean

NUMBER

VARCHAR

DATE

BOOLEAN

DECIMAL/DEC

VARCHAR2

INTERVAL

 

DOUBLE PRECISION

NVARCHAR2

TIMESTAMP

FLOAT

CHAR

 

INTEGER/INT

NCHAR

NUMERIC

CHARACTER

REAL

LONG

SMALLINT

LONG RAW

PLS_INTEGER

RAW

BINARY_DOUBLE

ROWID

BINARY_FLOAT...