What is SQL? How it's works on website? History of SQL?

 You use many websites on the internet every day, you must have installed many online apps in your mobile too, most of these apps and websites have your account created and your details are stored in their database.

 You must have known about the database.

 All your records database are always safe for years and years, whatever you share on Facebook or Twitter, you can see them even after years.

 You want to know what is SQL?  But, why are we talking about databases here?


 This is actually because SQL is attached to the database itself and with the help of this, a database is managed.

 Now let us know in detail what is SQL?  And what does it work for.

 What is SQL?

 The full form of SQL is Structured Query Language.  It is a type of computer language from which commands or instructions are given to a database.  Whether to create a database, store data, update or delete, there are different commands for all these, which is called SQL.


 All RDBMS (Relational Database Management System) uses SQL as a standard database language.


 Let's understand in easy words, let's say you want to create your account on Facebook, for this you have to fill a registration form.


 When you fill the form and click on submit button, all the data you have filled in the form will be stored in Facebook's database.

 But how will it work?

 When you click on the submit button, a SQL command will be executed in the back-end which will instruct the database to store the data.


 That is, the communication that is happening between the registration form and the database is in the language of SQL.



 What is the use of SQL?

 Let us now know what is the work of SQL and what are the operations related to the database through it:

 From SQL you can create a new database. You can retrieve data from a database, that is, use the data extracted. Insert new data into the database. Update or modify the existing data.  You can delete the data. Inside a database you can create a new table. You can also drop or delete a table. Create views, stored procedures, and functions. Permission set for tables, procedures and views  can do.

 That is, all the work in database management system can be done by SQL.

 How does SQL work in a website?

 All the dynamic websites on the internet are database driven.  Every dynamic sites like social media site, online banking, e-commerce, railway reservation are linked to the database and SQL is used where the database is.


 Now let's understand how SQL works in a live website.


 SQL alone cannot do anything in any website, for this, many things have to work together and for this some things are needed such as:

 DBMS Program (eg MySQL, SQL Server, MS Access, Oracle, Sqlite etc.) Server side scripting (eg PHP, ASP etc.) SQL commandsHTML, CSS

 RDBMS software like MySQL should be installed in your server, after that you will have to create dynamic web pages by programming through server side scripting like PHP or ASP and coding here to tell you which tasks you have to perform.


 According to the task you have to use SQL commands and these are called queries.  There are different queries for each task that you define within the programming of PHP or ASP.


 Now for the user interface you will also have to create pages of HTML and CSS so that the output of all these tasks can be visible to you or the user.

 History of SQL

 The first version of SQL was created in 1970 by Donald D. Chamberlin and Raymond F. Boyce at IBM called SEQUEL (Structured English Query Language) designed to retrieve data from IBM's database. Its name in 1973  The name was changed to SQL because the name SEQUEL was already a trademark of a company. After successfully testing SQL in 1978, IBM started making commercial products associated with it. Around 1986, Relational Software Inc.  Launched by RDBMS (Relational Database Management System), the company was later renamed Oracle.


 Some important commands of SQL -

 According to the work, these commands can be divided into three different categories:


 DDL (Data Definition Language):

 1.CREATE: This is used to create new objects in the database.
 2.ALTER: To modify database objects such as table etc.
3.DROP: To delete an object.

 DML (Data Manipulation Language):

1.SELECT: To retrieve data from one or more tables.  

2.INSERT: to enter a new record.
3.UPDATE: to modify the record.
4.DELETE: to delete a record.

 DCL (Data Control Language):

1.GRANT: To allow users.
2. REVOKE: To remove permission.