Home > Articles > Data > Oracle

Oracle PL/SQL Programming Concepts

PL/SQL is Oracle's Procedural Language extension to SQL. It is commonly used to write data-centric programs to manipulate data in an Oracle database. Here's a basic primer to help beginners get started.
This chapter is from the book

Chapter Objectives

In this Chapter, you will learn about:

  • The Nature of a Computer Program and Programming Languages

  • Good Programming Practices

Computers play a large role in the modern world. No doubt you realize how crucial they have become to running any business today; they have also become one of the sources of entertainment in our lives. You probably use computers for your everyday tasks as well, such as sending e-mail, paying bills, shopping, reading the latest news on the Internet, or even playing games.

A computer is a sophisticated device. However, it is important to remember that it is still only a device and cannot think on its own. In order to be useful, a computer needs instructions to follow. Facilities such as programming languages allow programmers to provide computers with a list of instructions called programs. These programs tell a computer what actions to perform. As a result, programming languages and computer programs play an important role in today's technology.

Lab 1.1 The Nature of a Computer Program and Programming Languages

Lab Objectives

After this Lab, you will be able to:

  • Understand the Nature of Computer Programs and Programming Languages

  • Understand the Differences between Interpreted and Compiled Languages

A computer needs instructions to follow because it cannot think on its own. For instance, when playing a game of solitaire you must choose which card to move. Each time a card is moved, a set of instructions has been executed to carry out the move. These instructions compose only a small part of the solitaire program. This program comprises many more instructions that allow a user to perform actions, such as beginning or ending a game, selecting a card's color, and so forth. Therefore, a computer program comprises instructions that direct the actions of the computer. In essence, a program plays the role of guide for a computer. It tells the computer what steps in what order should be taken to complete a certain task successfully.

Computer programs are created with the help of programming languages. A programming language is a set of instructions consisting of rules, syntax, numerical and logical operators, and utility functions. Programmers can use programming languages to create a computer program. There are many different programming languages available today. However, all programming languages can be divided into three major groups: machine languages, assembly languages, and high-level languages.


Words such as statement or command are often used when talking about instructions issued by a program to a computer. These terms are interchangeable.

Machine Languages

Machine language is the native language of a particular computer because it is defined by the hardware of the computer. Each instruction or command is a collection of zeros and ones. As a result, machine language is the hardest language for a person to understand, but it is the only language understood by the computer. All other programming languages must be translated into machine language. Consider the following example of the commands issued in the machine language.

For Example

Consider the mathematical notation X = X + 1. In programming, this notation reads the value of the variable is incremented by one. In the following example, you are incrementing the value of the variable by 1 using machine language specific to an Intel processor.

1010 0001 1110 0110 0000 0001
0000 0011 0000 0110 0000 0001 0000 0000
1010 0011 1110 0110 0000 0001

Assembly Languages

Assembly language uses English-like abbreviations to represent operations performed on the data. A computer cannot understand assembly language directly. A program written in assembly language must be translated into machine language with the help of the special program called an assembler. Consider the following example of the commands issued in assembly language.

For Example

In this example, you are increasing the value of the variable by 1 as well. This example is also specific to an Intel processor.

MOV AX, [01E6]
ADD AX, 0001
MOV [01E6], AX

High-Level Languages

A high-level language uses English-like instructions and common mathematical notations. High-level languages allow programmers to perform complicated calculations with a single instruction. However, it is easier to read and understand than machine and assembly languages, and it is not as time-consuming to create a program in high-level language as it is in machine or assembly language.

For Example

variable := variable + 1; 

This example shows the simple mathematical operation of addition. This instruction can be easily understood by anyone without programming experience and with basic mathematical knowledge.

Differences between Interpreted and Compiled Languages

High-level languages can be divided into two groups: interpreted and compiled. Interpreted languages are translated into machine language with the help of another program called an interpreter. The interpreter translates each statement in the program into machine language and executes it immediately before the next statement is examined.

A compiled language is translated into machine language with the help of the program called a compiler. Compilers translate English-like statements into machine language. However, all of the statements must be translated before a program can be executed. The compiled version of the program is sometimes referred to as an executable.

An interpreted program must be translated into machine language every time it is run. A compiled program is translated into machine language only once when it is compiled. The compiled version of the program can then be executed as many times as needed.

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information

To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.


Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.


If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information

Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.


This site is not directed to children under the age of 13.


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information

If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information

Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents

California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure

Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact

Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice

We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020