Introduction to SQL, Databases and RDBMS

In this post, we will see what is SQL and What it does.

What is SQL?

  • SQL stands for Structured Query Language.
  • Using SQL we can handle the database and data.
  • SQL is basiclly a language which gives the instructions to manage the data in database.

What is database?

  • Database is a collection of structured information.
  • It is made up of tables which actually stores the data in a row format, and these tables are connected to each other.

What SQL does?

  • SQL is used to create the databases and tables.
  • It also helps to store and retrive the data in tables.
  • Using SQL we can perform various operations on this data, operations like update, delete.
  • We can delete databases, trucate tables using SQL.

What is RDBMS?

  • RDBMS is Relational Database Management System.
  • All the database systems such as MySQL, Oracle, Microsoft Access are based on RDBMS.
  • We are going to use MySQL in further posts.

Types of SQL commands

Since SQL is a Query language. Its commands are classified into different groups based on their different usage.

DDL(Data Definition Language):- DDL statements are used to create, drop the table and databases. Also, we can truncate(wiping whole data) and alter(update) the table.

DML(Data Manipulation Language):- DML statements are used to insert, update and delete the data.

DQL(Data Query Language):- DQL is used to view the data from tables. Using DQL we can select which data we need to see.

There are some other advanced statements also, which are used to do advanced operations.

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