Introduction to SQL: What is SQL and how do you get started learning SQL?

Preface:

In our daily lives, we use a large number of apps, gadgets and devices. It generates a huge amount of data every second. SQL provides a standard way to work with such data. In this article, I’ll explain to you what SQL is and how it evolves.

This article covers the following topics:

Problems with traditional file systems

Data storage has been one of the major concerns of people since the beginning of the computer era. In the past, we often stored data in file-based systems, which led to improper data management. Although seemingly organized, it has its own inherent flaws:

1. Data redundancy

Duplicate data occurs when the same data is stored in different places in our computer system. In the file system, there is no real-time checking for duplicate files. This increases the size of the structure and leads to a lack of security features. As a result, file systems are inherently vulnerable.

2. Limited data sharing and lack of security

Data sharing is closely related to security, and sharing data among geographically dispersed users poses a number of security risks. The built-in file system program provides basic security for spreadsheet data and other documents, but few people use it, or even know about it.

Security and data sharing capabilities are often unlocked in the creation of data management and reporting programs, so they are generally ignored in file system environments. These features include effective password protection, the ability to lock some files or parts of the system itself, and other measures designed to protect the confidentiality of data. Even when they are used, they are not sufficient to achieve reliable data sharing between users.

3. The difficulty of quick answers

Another important problem with traditional file environment systems is that it is difficult to get quick answers because it requires more ad-hoc queries, more procedures to process, and therefore, timely responses.

4. Data dependency

In a file system, files and records consist of specific physical formats that are encoded by a programmer into an application. If the format of any record changes, then we need to ensure that all remaining record formats are updated. This information must also be updated in the system. Any change in the storage structure or access method can significantly affect the processing or results of an application.

Because of all of these disadvantages and other limitations, a new technology needed to be implemented, and SQL was born.

The development of SQL

SQL was developed by Donald Chamberlin and Raymondf Boyce at IBM in the 1970s. It was originally called Sequel, but has since been changed to SQL. It was changed because Sequel is a UK engineering company. In SQL, data is stored as a relationship. This relationship theory was developed by Boyce and Chamberlin.

It wasn’t until several years later that the SQL language was made public. The first company to publish a modified version of SQL was Relational Software, Inc. (now Oracle), which called it Oracle V2. Thereafter, the American National Standards Institute (ANSI) and the International Standards Organization took SQL as the standard language for relational database communication. Today, SQL is recognized as the standard language for relational database management systems.

So, what is SQL?

Structured query languageStructuredQueryLanguage (SQL) is pronounced “S-Q-L”, or sometimes “Seequel”, which is the standard language for dealing with relational databases. Let’s take another practical example to understand what SQL really is.

If two people want to communicate with each other, they must use a language that they both understand. If we consider these two people, one as a user and the other as a database, then the language used to communicate between them is called SQL. Similarly, how a language has syntax and various rules to guide its use, and even SQL has its own instructions.

SQL is effectively used to insert, search, update, delete, and modify database records. This does not mean that SQL cannot do things beyond this scope. In fact, it can do a lot more.

Now that we know what SQL is, let’s look at its processing capabilities:

• DDL (Data Definition Language) provides SQL commands for defining, deleting, and modifying relational schemas.
• Data processing language (DML) provides a query language based on relational algebra and tuple calculus.
• Embedded DML is used for general-purpose programming languages.
• The DDL contains commands for defining views.
• The DDL command is used to specify access rights to relationships and views.
• SQL provides integrity checking.

Let’s look at some of the most popular basic queries in SQL.

Create a database: The syntax for this database is

create Database database_name;

Delete a database that has been created:

drop Database database_name;

Create a table in the database

create Table table_name;

Delete a previously existing table

drop Table table_name;

So, if you want to learn more about SQL queries, take a look at my article on SQL basics to help you get started with SQL

The advantage of SQL

Now that we know all about SQL, it’s time to understand its benefits.



SQL has well-defined standards

As it says, SQL developers have talked about how to write every query, and when you write a query, there is no room for ambiguity, and you have to follow standards.

2. Easy to learn

SQL is a language for working with databases, and because SQL has a large user base and well-defined standards, it is really easy for beginners to learn.

3. In SQL, we can create multiple views

This is one of the unique and early features of SQL, where a view simply creates a virtual table, which is a temporary table used for some purpose, to protect the integrity of the data, and SQL can create not just one view, but multiple views.

SQL queries are portable

This means that we can execute SQL queries on one system and execute the same queries on another system without changing the format. However, the environment Settings for these systems must be the same, or the query will not be executed

5. It’s an interactive language

The main purpose of SQL is to communicate with a database, and we can write complex queries to get results from a database that can be easily understood by anyone.

Now, let’s look at some of its real-time applications

Real-time SQL

Since SQL is a language for manipulating databases, we need to look at the big picture of the data management industry, which includes SQL in this reference to databases. Databases can be used in many industries, such as e-commerce, medicine, clubs, libraries, video sites, beauty salons, travel agencies, operators, government agencies, etc.

1. Finance

Managing money, assets, stocks, and so on in real time can be a tedious task. SQL and database technologies are helping the financial sector accomplish its primary task. SQL queries can also be used to detect fraudulent activity.



2. Education sector

Database systems are often used in schools, colleges and universities to store and retrieve data about student details, faculty details, course details, examination details, payroll data, attendance details, fee details, etc., requiring efficient storage and retrieval of a large number of interrelated data.

3. Health care sector

Maintaining data related to doctors, patients, and staff is a huge task in hospitals and healthcare facilities, and effective coordination between all three must be handled seamlessly, and with the help of SQL and databases, the industry has grown a lot.

4. Retail

In retail, customer data must be managed effectively. There are no errors when processing the data. With the help of SQL and database systems, the retail industry can not only guarantee the security of data, but also can conduct real-time analysis.