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SQL Tutorial

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Anusha Hiremath
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2 min read

What is Database(DB)? Any collection of related information For Example: Phone Book, Shopping list, ToDo List,

Databases can be stored in different ways such as On paper, On your computer etc.

What is Database Management Systems(DBMS)? A special software program that helps users create and maintain database.

  • Makes it easy to manage large amounts of information
  • Handles security
  • Backups
  • Importing/Exporting data
  • Interacts with software applications.

In Database we have four operations that is Create, Read, Update and Delete.

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Two types of Databases:

Relational Databases(SQL) : Organize data into one or more tables and each table has columns and rows, a unique key identifies each row. Helps users create and maintain a relational database. mySQL, Oracle, postgreSQL, etc

Structured Query Language(SQL) Used to perform CRUD operations as well as other tasks like user management,backup etc. Used to define tables and sturctures.

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Non-relational Databases(NoSQL): Organize data is anything but a traditional table i.e., Documents(JSON/XML), Graphs, Flexible Tables. Helps users to create and maintain non-relational database i.e., mongoDB, firebase etc.

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Database Queries: Queries are requests made to the database management system for specific information. A google search is a Query.

The following functionalities can be performed on a database using SQL:

  1. Create or Delete a Database.
  2. Alter a Database
  3. Select data from tables.
  4. Insert data into tables.
  5. Update data in tables.
  6. Delete data from tables and much more.....

SQL Datatypes:

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SQL Commands: SQL Commands are instructions that are used by the user to communicate with the database, to perform specific tasks, functions and queries of data.