alternative
  • Home (current)
  • About
  • Tutorial
    Technologies
    C#
    Deep Learning
    Statistics for AIML
    Natural Language Processing
    Machine Learning
    SQL -Structured Query Language
    Python
    Ethical Hacking
    Placement Preparation
    Quantitative Aptitude
    View All Tutorial
  • Quiz
    C#
    SQL -Structured Query Language
    Quantitative Aptitude
    Java
    View All Quiz Course
  • Q & A
    C#
    Quantitative Aptitude
    Java
    View All Q & A course
  • Programs
  • Articles
    Identity And Access Management
    Artificial Intelligence & Machine Learning Project
    How to publish your local website on github pages with a custom domain name?
    How to download and install Xampp on Window Operating System ?
    How To Download And Install MySql Workbench
    How to install Pycharm ?
    How to install Python ?
    How to download and install Visual Studio IDE taking an example of C# (C Sharp)
    View All Post
  • Tools
    Program Compiler
    Sql Compiler
    Replace Multiple Text
    Meta Data From Multiple Url
  • Contact
  • User
    Login
    Register

SQL -Structured Query Language - Normalization - 1 NF Tutorial

  • Each record must be unique.
  • Each cell must contain a single value.

 

For example-

The 1st table is not 1 NF form because of multiple values in single-cell – contact_no.

But after splitting the row uniquely and single value in a single cell, the 2nd table becomes 1NF form.

Here the composite key is used to identify rows.

Now, what are the primary key and composite key?

Primary keys are unique, cannot be null, and auto-increment.

But this table doesn’t contain a primary key.

 

Hence we use here a composite key

A composite key is a combination of two or more column which is used to identify a record uniquely. It acts as a primary key.

 

For example-

 

Here user_id,first_name,last_name are common. Only difference is contact_no.

Hence we use user_id,contact_no or first_name,contact_no or last_name,contact_no to uniquely identify the records.

SQL -Structured Query Language

SQL -Structured Query Language

  • Introduction
  • Overview
    • How To Download And Install MySql Workbench
    • SQL Syntax
  • SQL Database
    • Create Database
    • Drop Database
    • Use / Select Database
  • SQL Table
    • Create Table
    • Alter - Rename Table
    • Alter - Add Column
    • Alter - Modify Column
    • Alter - Rename Column
    • Alter - Drop Column
    • Copy Table
    • Drop Table
  • SQL Insert
    • Insert Record
  • Sql Update
    • Update Record
  • Sql Select
    • Select Record
    • Select - Count
    • Select - Average
    • Select - Sum
    • Select - Min Max
    • Select - Distinct
    • Select - Limit
    • Select - First
    • Select - Last
  • Sql Clause
    • Like Clause
    • And Operator
    • Or Operator
    • Between & Not Between Operator
    • As or Alias
    • In Clause
    • Group By Clause
    • Having Clause
  • Sql Order By
    • Ascending
    • Descending
    • Random
    • Ascending Descending Multiple Column
  • SQL Joins
    • Joins and its type
    • Inner Join
    • Left Join
    • Right Join
    • Full Join
    • Cross Join
  • SQL View
    • Create View
    • Update View
    • Delete View
  • SQL Delete
    • Delete Table
    • Truncate Table
  • Sql Key & Constraint
    • Primary Key
    • Foreign Key
    • Unique Key
    • Not Null Constraint
    • Check Constraint
    • Default Constraint
  • Normalization
    • Overview
    • 1 NF
    • 2 NF
    • 3 NF
    • Boyce Codd normal form ( BCNF )

About Fresherbell

Best learning portal that provides you great learning experience of various technologies with modern compilation tools and technique

Important Links

Don't hesitate to give us a call or send us a contact form message

Terms & Conditions
Privacy Policy
Contact Us

Social Media

© Untitled. All rights reserved. Demo Images: Unsplash. Design: HTML5 UP.