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THE NOID
THE NOID

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WHAT IS SQL ?

#sql #sqlplus #dbms #rdbms

SQL stands for Structured Query Language. It is used to design and manage data in databases.

EXPLANATION :

Every application which we using today works with data.

Our instagram profile, Amazon orders, Bank Transactions, and even our YouTube history is stored somewhere.

But storing data is only one part of the problem. We also need a way to find, update, and manage that data.

This is where SQL comes in.

FOR EXAMPLE :

  • Get all users from a database

  • Add a new customer

  • Change a user's information

  • Delete Records

  • Find specific data

UNDERSTANDING DATABASE :

Before learning SQL, we need to understand what a database is :

A database is a place where information is stored, organized, and managed so that we can easily find, use, and update it whenever needed.

NOTE : We can create multiple databases and each database can contain multiple tables.

We can create databases inside a Database Management System [ DBMS ] or Relational Database Management System [ RDBMS ].

UNDERSTANDING DBMS & RDBMS :

  1. DBMS : A Database Management System is software that helps use to store, organize, and manage data in database easily but it's non relational.

Ex : Microsoft Access, SQLite, MongoDB

  1. RDBMS : An RDBMS is a type of DBMS that stores data in tables and connects realted tables using relationship.

It is smaller subset of DBMS and designed by E.F. Codd in 1970.

Ex : Oracle Database, MySQL, Microsoft SQL Server

TYPES OF SQL :

HOW TO PRACTICE : [ MY APPROACH ]

  1. YouTube Channel : LEARN CODING SQL

  2. Practice Platform : SQL BOLT, HACKERRANK SQL

SQLPLUS INSTALLATION AND SETUP GUIDE :

I used SQLPlus in the Command Prompt because it helps me practice more. Unlike tools like Oracle SQL Developer or MySQL Workbench, you can't easily edit your queries in SQLPlus. Everything is done in the Command Prompt. If you make a mistake, you have to type the query again instead of editing it. This gives you more practice and helps you improve your SQL skills.

Steps :

  1. Browse this link : SQL PLUS

  2. Download the Oracle Database Express Edition (11g) version. It is lightweight and fast.

  3. During the installation, set a password. You will use this password later to log in through the Command Prompt.

  4. After the installation is complete, open Command Prompt and type: sqlplus

  5. Enter the username as system and the password that you created during the installation.

  6. That's it! You are now connected to SQL*Plus.

  7. Start practicing SQL queries on your own.

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