PL/SQL Basics - Unit-III - PL/SQL Basics (RDBMS Unit-III)

Oct 14, 2026

Upload by Levi

PL/SQL Basics explains PL/SQL as Oracle’s procedural extension of SQL, designed to enhance SQL capabilities with portability, high-performance transaction processing, and an OS-independent interpreted environment. The content covers key features such as tight SQL integration, extensive error checking, multiple data types, structured programming via functions and procedures, and support for object-oriented and web application development. It further details the core block structure (DECLARE, BEGIN/END, EXCEPTION), identifier rules, commenting syntax, program units, and essential data type categories like scalar, LOB, composite, and reference.

LanguageEnglish

CategoryGeneral

FormatPDF

Pages21

Reading Time7 min

AccessFree to download

PL/SQL Basics

Features and Advantages of PL/SQL

PL/SQL Basic Syntax

Hello World Example

PL/SQL Identifiers and Comments

PL/SQL Program Units

PL/SQL Data Types

PL/SQL Basics PL/SQL is a combination of SQL along with the procedural features of programming languages. It was developed by Oracle Corporation in the early 90's to enhance the capabilities of SQL. PL/SQL is one of three key programming languages embedded in the Oracle Database, along with SQL itself and Java. 􀂷 PL/SQL is a completely portable, high-performance transaction-processing language. 􀂷 PL/SQL provides a built-in, interpreted and OS independent programming environment. 􀂷 PL/SQL can also directly be called from the command-line SQL*Plus interface. 􀂷 Direct call can also be made from external programming language calls to database. 􀂷 PL/SQL's general syntax is based on that of ADA and Pascal programming language. Features of PL/SQL PL/SQL has the following features 􀂷 PL/SQL is tightly integrated with SQL. 􀂷 It offers extensive error checking. 􀂷 It offers numerous data types. 􀂷 It offers a variety of programming structures. 􀂷 It supports structured programming through functions and procedures. 􀂷 It supports object-oriented programming. 􀂷 It supports the development of web applications and server pages. Advantages of PL/SQL PL/SQL has the following advantages − 􀂷 SQL is the standard database language and PL/SQL is strongly integrated with SQL. PL/SQL supports both static and dynamic SQL. Static SQL supports DML operations and transaction control from PL/SQL block. In Dynamic SQL, SQL allows embedding DDL statements in PL/SQL blocks. 􀂷 PL/SQL allows sending an entire block of statements to the database at one time. This reduces network traffic and provides high performance for the applications. 􀂷 PL/SQL gives high productivity to programmers as it can query, transform, and update data in a database. 􀂷 PL/SQL saves time on design and debugging by strong features, such as exception handling, encapsulation, data hiding, and object-oriented data types. 􀂷 Applications written in PL/SQL are fully portable. 􀂷 PL/SQL provides high security level. 􀂷 PL/SQL provides access to predefined SQL packages. 􀂷 PL/SQL provides support for Object-Oriented Programming. 􀂷 PL/SQL provides support for developing Web Applications and Server Pages. PL/SQL-Basic Syntax PL/SQL programs are divided and written in logical blocks of code. Each block consists of three sub-parts Declarations This section starts with the keyword DECLARE. It is an optional section and defines all variables, cursors, subprograms, and other elements to be used in the program. Executable Commands This section is enclosed between the keywords BEGIN and END and it is a mandatory section. It consists of the executable PL/SQL statements of the program. It should have at least one executable line of code, which may be just a NULL command to indicate that nothing should be executed. Exception Handling This section starts with the keyword EXCEPTION. This optional section contains exception(s) that handle errors in the program. DECLARE BEGIN EXCEPTION END; The 'Hello World' Example DECLARE message varchar2(20):= 'Hello, World!'; BEGIN dbms_output.put_line(message); END;/ The PL/SQL Identifiers PL/SQL identifiers are constants, variables, exceptions, procedures, cursors, and reserved words. The identifiers consist of a letter optionally followed by more letters, numerals, dollar signs, underscores, and number signs and should not exceed 30 characters. The PL/SQL Comments The PL/SQL supports single-line and multi-line comments. All characters available inside any comment are ignored by the PL/SQL compiler. The PL/SQL single-line comments start with the delimiter --(double hyphen) and multi-line comments are enclosed by /* and */ . DECLARE --variable declaration message varchar2(20):= 'Hello, World!'; BEGIN /* * PL/SQL executable statement(s)*/ dbms_output.put_line(message); END; / When the above code

FAQs

What is PL/SQL and how is it related to SQL?

PL/SQL combines SQL with procedural programming features. It is tightly integrated with SQL so PL/SQL blocks can use static and dynamic SQL.

What are the three parts of a basic PL/SQL program block?

A PL/SQL block consists of DECLARE (optional), BEGIN ... END (mandatory executable section), and EXCEPTION (optional) for handling errors.

What rules apply to PL/SQL identifiers?

Identifiers can be letters followed by letters, numerals, dollar signs, underscores, and number signs, and must not exceed 30 characters. Reserved words cannot be used as identifiers.

Oct 14, 2026

Upload by Levi