Book Image

Oracle Advanced PL/SQL Developer Professional Guide

By : Saurabh K. Gupta
Book Image

Oracle Advanced PL/SQL Developer Professional Guide

By: Saurabh K. Gupta

Overview of this book

PL/SQL (Procedural Language/Structured Query Language) is Oracle Corporation's procedural extension language for SQL and the Oracle relational database. Server-side PL/SQL is stored and compiled in the Oracle Database and runs within the Oracle executable. With this guide Oracle developers can work towards accomplishing Oracle 11g Advanced PL/SQL Professional certification, which is the second milestone for developers working at the Associate level. The Oracle Advanced PL/SQL Developer Professional Guide helps you master advanced PL/SQL concepts. Besides the clear and precise explanation on advanced topics, it also contains example code and demonstrations, which gives a sense of application and usage to readers.The book gives a deep insight that will help transform readers from mid-level programmers to professional database developers. It aims to cover the advanced features of PL/SQL for designing and optimizing PL/SQL code.This book starts with an overview of PL/SQL as the programming database language and outlines the benefits and characteristics of the language. The book then covers the advanced features that include PL/SQL code writing using collections, tuning recommendations using result caching, implementing VPD to enforce row level security, and much more. Apart from programming, the book also dives deep into the usage of the development tool SQL Developer, employing best practices in database environments and safeguarding the vulnerable areas in PL/SQL code to avoid code injection.
Table of Contents (22 chapters)
Oracle Advanced PL/SQL Developer Professional Guide
Credits
Foreword
About the Author
Acknowledgement
About the Reviewers
www.PacktPub.com
Preface
Index

Chapter 6, Working with Large Objects


Question No.

Answer

Explanation

1

a

LOBs can appear as a database column or a user defined object type attribute.

2

b

LOB type parameters can exist.

3

a

LOB data greater than 4 K is stored out of line with the current row. Mandatorily, it's a different LOB segment which may or may not be in the same tablespace.

4

b

The BLOB column must be initialized with EMPTY_BLOB()

5

c

The constructor methods EMPTY_CLOB() and EMPTY_BLOB() are used to initialize NULL and NOT NULL LOB types.

6

b and c

FILEOPEN works only with BFILEs.

7

b

Temporary LOBs are session specific.

8

c and d

BFILE is a read-only type. The files accessed through the BFILE locator open in read-only mode. They cannot be manipulated in any way during the BFILE access.

9

b and d

Temporary LOB is always an internal LOB which is used for manipulative actions in the LOB columns within a block.

10

c

The user must have read/write privilege on the directory to access the files contained in it.

11

b

A LONG column can be migrated to a LOB column using the following syntax:

ALTER TABLE [<schema>.]<table_name>
   MODIFY ( <long_column_name> { CLOB | BLOB | NCLOB } 
  [DEFAULT <default_value>]) [LOB_storage_clause]

Note that a LONG column can be migrated to CLOB or NCLOB while a LONG RAW column can be modified to BLOB only.

12

b

The BFILENAME function is used to return the LOB locator of a file which is located externally. It can be used for internal LOBs as well as external LOBs.

13

b and d

SecureFile is a new feature in Oracle 11g to store large objects with enhanced security, storage, and performance. Older LOBs may still exist as BasicFiles and can be migrated to SecureFiles.

14

a and c

The CREATE TABLE script executes successfully. The table and LOB are created in the default user tablespace. Oracle implicitly generates the LOB segment and LOB index. However, the segments are not created until the data has been inserted in the table.