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Basics of Normalization

  • Normalization is method or technique used to eliminate data redundancy and ensures the data integrity between tables.

    • It decreases data redundancy.
    • It ensures the data integrity of tables.
  • There are three types of Normalizations

    • 1NF (First Normal Form)
    • 2NF (Second Normal Form)
    • 3NF (Third Normal Form)
  • 1NF (First Normal Form) -

    • First normal form in this table the data should not be repeating in single row.
    • Every row and data must be unique.


    • In above example we have two author data in single column and single row.
    • Now if we use First Normal Form we eliminate the repeating data.


  • 2NF (Second Normal Form) -

    • It is already in First Normal Form, which means each row and data is unique.
    • All data are fully dependent on primary key.
    • It divides tables in multiple tables which helps to improve data integrity and reduce data redundancy.
    • It helps to organize the data and tables in database.

    ![Untitled](- It is already in First Normal Form, which means each row and data is unique.)

    • In above example we have where CourseID is primary key and there are total 3 columns,
    • Now using Second Normal Form we can divide the data referencing primary key in other tables.



  • 3NF (Third Normal Form) -

    • Must be Second Normal Form before Third Normal Form.

    • No non-key attributes are directly dependent on the primary key


    • Now using Third Normal Form we can divide single table into two tables using one of the column data and referencing a column from one table into another table.



Advantages of normalization —

  • Reduces data redundancy and inconsistency.
  • Helps achieving data integrity.
  • Provides clear structure to the data.
  • Makes data retrieval more efficient.
  • By organizing data it'll enhances the reliability of the database.
  • Normalization improves performance of the database and makes it faster.

Disadvantages of normalization —

  • Very complex to implement.
  • May require extra joins in tables to make it work.
  • Makes the structure complex which can slow down the queries and processes.
  • It increases the database size.
  • Using normalization it can reduce flexibility.

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