What is SQL (Structured Query Language)? Usage Areas and Examples

SQL, which is one of the basic languages ​​that software developers should know, often heard by those who are closely interested in the computer world, gains great importance in critical moments. SQL, which is frequently used for database operations, is wondered by those who are very new to learning software. In this article, we answered all the questions about SQL for you.

What is SQL?

SQL ( Structured Query Language ) means structured query language in Turkish . This language is not considered any programming. SQL is used for data management and many databases, especially relational databases, are managed through the SQL language. Thanks to SQL commands, new data is added to the database, existing data can be changed or completely deleted. Apart from this, special lists are also created. 

SQL is a query language introduced in the search for new ways to manage databases. Before using SQL , SQUARE is used , then SEQUEL is developed, and finally SQL is used.

What Does SQL Do? What are the advantages?

With SQL, created databases are managed much more easily and reliably. 

You can categorize your data very easily with SQL. Since the information is categorized in a healthy way, you also get rid of clutter. 

With SQL, you can pull new data , edit this data, update all of the data, query and record the data, and create new databases. 

Finding what you are looking for among the data often takes a long time and causes a waste of time. SQL eliminates this situation as well.

Nowadays, SQL is used almost everywhere where there is a database. SQL makes great contributions to every transaction performed over the  Internet or network.

It is a very easy system to learn and understand. 

It is flexible and integrated to work with many knowledge base systems.

How Does the SQL System Work?

SQL works with the command system. Commands are given to perform some operations and these commands or instructions are called queries. The system takes this query as input and gives the desired output. 

The SQL system first requests that the query be converted from high to low language. For this reason, SQL queries are translated into some algebraic expressions.

It is possible to write the same query in several different ways. But to get the best results, it is necessary to write in the best way. Here, too, the 'query optimizer' comes into play. It allows to optimize the query in a way that it can be efficient.

In the last step, all possible permutations and combinations are generated to find the best and shortest query. In this last step, the optimized query is evaluated and presented to the users.

SQL Commands

DQL, that is, the data query language, is used to get information from the database. In SQL language the command is known as SELECT. 

DDL, or data definition language, serves to create, destroy and maintain the database when necessary. It deals directly with the schema of the database. In SQL language it is known as CREATE, DROP, ALTER, TRUNCATE, COMMENT, RENAME. 

DML, that is, data processing language, serves to store and change the data in the database. Its command in SQL language is known as INSERT, UPDATE, DELETE and MERGE. 

DCL, the data control language, prevents abuse and protects data. The SQL equivalent is known as GRANT and EVOKE. 

TCL, the transaction control language, allows to maintain database-related transactions. Its commands are known as TRANSACTION, COMMIT, ROLLBACK, and SAVEPOINT. 

SQL Uses and Examples

SQL is widely used in many fields today. Let's examine these areas now.

SQL is widely used in the financial industry today. Internet banking stores data about payment methods, financial transactions and users in an extremely secure manner. 

Every time we browse social media, we leave dozens of data. When this is the case, it is inevitable to use SQL. For this reason, SQL is also used in social media platforms to store, organize and delete this data. Instagram and Snapchat are the most well-known of them. 

Music apps are also known as places where we leave our data, just like social media platforms. And yet, these platforms also use SQL. 

The marketing industry also attaches importance to the use of SQL. Data-driven marketing uses SQL for better analysis and insight 

Some Databases Using SQL Language

• Microsoft Access

• MySQL

• Firebird

• Progress

• Oracle

• IBM DB2

• PostgreSQL

• IBM Informix

• Sybase

• Microsoft SQL Server