database management system chapter5

Teaching Aid Material

(www.phindia.com/gupta)

Authors invite your valuable feedback and suggestions on the [email protected]

[email protected]

DATABASE MANAGEMENT SYSTEM ORACLE SQL AND PL/SQL

PART II : Application Using Oracle PL/SQL

CHAPTER 5

Introduction to PL/SQL Programming


PART II : Application Using Oracle PL/SQL

CHAPTER 5Introduction to PL/SQL Programming

1 of 9

Why PL/SQL?

Better Performance

Higher Productivity

Full Portability

Tight Integration with SQL

Security

Page reference in the book: 147-152


2 of 9

Character Set

Type Characters

Uppercase, lowercase A-Z , a-z

Digits 0-9

Mathematical and punctuation symbols

~ ! @ # % & * ( )_ - + = | [ ] { }: ; ’’ ’ < > ? /

White space Space, tab, carriage return



3 of 9

PL/SQL Identifiers

Identifiers are used to name PL/SQL objects such as constants,variables, exceptions, procedures, cursors and reserved words.

Identifiers can be up to 30 characters in length, must start with aletter and can include dollar sign, an underscore, and a pound sign.

Identifiers are case sensitive and cannot include space, tab orcarriage return. An identifier can be enclosed within double quotes.



4 of 9

PL/SQL Literals

Literals are specific values and are not represented by identifiers

Can be character, number or Boolean value

To embed single quotes within a string literal, two single quotes next to each other may be placed



5 of 9

PL/SQL Delimiters Delimiters are symbols with special meaning to PL/SQL Used to separate identifiers from each other

Delimiter Characteristics

-- Single-line comment indicator

/* */ Multiline comment delimiter

|| Concatenation operator

.. Range operator

; Statement terminator



6 of 9

PL/SQL Variable

Type Purpose

Scalar Numeric NUMBER(p, s)The maximum precision is 38 digits

Character VARCHAR2, CHAR, LONGCHAR and VARCHAR2 are up to 32767 bytes

Date Range is between 01-Jan-4712BC and 31-Dec-9999AD

Boolean Can hold TRUE, FLASE or NULL only

RAW Similar to CHAR variablesLONG RAW is similar to LONGLONG RAW can be up to 2 gigabytes



7 of 9

PL/SQL Variable

Type Purpose

LOB BFILE File locaters pointing to read only large objects in operating system files

BLOB BLOB locaters that point to large binary objects inside the database

CLOB CLOB locaters point to large character objects inside the database

NCLOB NCLOB locaters point large national character set objects inside the database



8 of 9

NULL Represents unknown values as NULL values NULL is never equal to anything NVL, IS NULL or IS NOT NULL

CONSTANT Requires an initial value Value cannot be changed



9 of 9

Default Value

A variable is assigned a default value of NULL while declaration

Can be initialized by assignment operator (: =)


CHAPTER 5PL/SQL Structure

1 of 3

PL/SQL Structure

DeclareVariables, Cursors, Constants

BeginPL/SQL statementsException

Statements for error handlingEnd;



2 of 3

IF Statement

Allows actions based upon conditions

IF statement can also be nested

Three forms of IF statements:

IF … THEN …IF … THEN … ELSE … IF … THEN … ELSIF … ELSE ….



3 of 3

Loops in PL/SQL

Simple LoopLoop

PL/SQL statementsExit Condition

End Loop

For LoopFor variable IN Start..End

PL/SQL StatementsEnd Loop;

While LoopWhile <Condition> Loop

PL/SQL StatementsEnd Loop


CHAPTER 5PL/SQL and Oracle

1 of 10

Scope of a Variable in Nested Block

PL/SQL statements can be nested

SQL Cursor

A cursor is a private SQL work area where all commandsdefined in the cursor are executed

There are two types of cursors: Implicit cursor Explicit cursor



2 of 10

Implicit Cursor

It is automatically created and handled by Oracle Server

Support all types of DMLs [Insert/Update/Delete]

Supports SELECT statement that returns only

Explicit Cursor

Needs to be declared explicitly by the programmer

It is handled using cursor-related commands



3 of 10

INTO Clause Into clause is mandatory in a PL/SQL program It is placed between SELECT and FROM clauses Acts as a container with the associated variable Query must return only one row

%TYPE Attribute

Used to declare variables that refer to the column

% ROWTYPE Attribute Represents a row in a table



4 of 10

Example EX5_1



5 of 10

EX5_2



6 of 10

EX5_3



7 of 10EX5_5



8 of 10

EX5_10



9 of 10EX5_11



10 of 10

EX5_12


CHAPTER 5Short/ Objective Type Question

Q1. Define identifiers, literals and delimiters in Oracle PL/SQL.

Q2. Explain %TYPE and %ROWTYPE attributes with the help of suitable examples.

Q3. What do you understand by SQL cursors?

Q4. Write a PL/SQL program which will accept three numbers and print the smallest among them.SQL>@ C:/TTP/Q4Enter value for a: 12Enter value for b: 34Enter value for c: 12Smallest Number is 12

Q5. Write PL/SQL program using Loop … End Loop, For Loop and While Loop, which will accept integer from 1 to 10 and print factorial. For example, factorial of 5 is 5*4*3*2*1=120.

SQL>@ C:/TTP/Q5Enter value for i_num: 6FACTORIAL OF 6 IS 720

CHAPTER 5Short/Objective Type Question

Q6. Write a PL/SQL program which will accept a number from 1 to 20 and display following the the figure.SQL>@ C:/TTP/Q8Enter value for i_num: 10

-- *---- *------ *-------- *---------- *------------ *-------------- *---------------- *------------------ *-------------------- *

Q7. The basic programming unit of a PL/SQL code is a (a) Procedure(b) Subprogram(c) Module(d) Block

Q8. Which of the following sections of a PL/SQL program are optional?(a) Declarative Section(b) Exception Handler Section(c) Executable Section(d) All of these

CHAPTER 5Home Assignment

WORKOUT

Periods Proposed – 18Chapter 5Introduction to PL/SQL Programming

1 Period [Theory]1 Period [Practical]

Chapter 6Oracle Function, Procedure And Package


Chapter 7Oracle Exception Handler and Database Triggers


Chapter 8Implicit and Explicit Cursors

1 Period [Theory]2 Periods [Practical]

Chapter 9Advance Cursors


Chapter 10PL/SQL Collection


Chapter 11Oracle Objects and Dynamic SQL


Chapter 12Performance Tuning



PART II : Application using Oracle PL/SQL

THE BOOKThe book is organized into three parts to introduce thetheoretical and programming concepts of DBMS. Part I(Basic Concepts and Oracle SQL) deals with DBMS basic,software analysis and design, data flow diagram, ER model,relational algebra, normal forms, SQL queries, functions,sub‐queries, different types of joins, DCL, DDL, DML, objectconstraints and security in Oracle. Part II (Application UsingOracle PL/SQL) explains PL/SQL basics, functions,procedures, packages, exception handling, triggers, implicit,explicit and advanced cursors using suitable examples. Thispart also covers advanced concepts related to PL/SQL, suchas collection, records, objects, dynamic SQL andperformance tuning. Part III (Advanced Concepts andTechnologies) elaborates on advanced database conceptssuch as query processing, file organization, distributedarchitecture, backup, recovery, data warehousing, onlineanalytical processing and data mining concepts and theirtechniques.

KEY FEATURES Includes about 300 examples to illustrate the concepts. Offers about 400 objective type questions. Provides about 100 challenging workouts.

TEACHING AID MATERIALTeaching Aid Material for all the chapters is provided on thewebsite of PHI Learning. Visit www.phindia.com/gupta toexplore the contents.

Visit PHI Learning Center www.phindia.com/gupta and Click on Instructor Resources toaccess Teaching Aid Material for all the 18 chapters of the book.

database management system chapter5

Education

plsql programming

plsql objects

plsql structure

plsql identifiers identifiers

plsql delimiters delimiters

plsql literals literals

nested block plsql statements

sqlsecuritypage reference