What is Normalization ?

Answer : Normalization is the process of reorganizing data in a database…
  • Normalization is the process of reorganizing data in a database. They have two basic requirements they are:
    • No redundancy of data.
    • Logical as data dependencies.
  • To normalize a database, we divide the database into tables and establish relationships between the tables.
  • Database normalization can essentially be defined as the practice of optimizing table structures.
  • Optimization is accomplished as a result of a thorough investigation of the various pieces of data that will be stored within the database, in particular concentrating upon how this data is interrelated.
 What is Normalization

Types of Normalization

  • 1NF
  • 2NF
  • 3NF
  • BCNF
  • 4NF
  • 5NF

First Normal Form (1NF)

  • The First Normal Form should be following some rules in table,
    • It should only have single(atomic) valued attributes/columns.
    • Values stored in a column should be of the same domain
    • All the columns in a table should have unique names.
    • And the order in which data is stored, does not matter.

Second Normal Form (2NF)

  • For a table to be in the Second Normal Form,
    • It should be in the First Normal form.
    • And, it should not have Partial Dependency.

Third Normal Form (3NF)

  • A table is said to be in the Third Normal Form when,
    • It is in the Second Normal form.
    • And, it doesn’t have Transitive Dependency.

Boyce and Codd Normal Form (BCNF)

  • Boyce and Codd Normal Form is a higher version of the Third Normal form. This form deals with certain type of anomaly that is not handled by 3NF. A 3NF table which does not have multiple overlapping candidate keys is said to be in BCNF.
  • For a table to be in BCNF, following conditions must be satisfied:
    • R must be in 3rd Normal Form and, for each functional dependency ( X → Y ), X should be a super Key.

Fourth Normal Form (4NF)

  • A table is said to be in the Fourth Normal Form when,
    • It is in the Boyce-Codd Normal Form.
    • And, it doesn’t have Multi-Valued Dependency.

Fifth Normal Form (5NF)

  • Fifth Normal Form (5NF), also known as project-join normal form (PJ/NF) is a level of database normalization designed to reduce redundancy in relational databases recording multi-valued facts by isolating semantically related multiple relationships.
  • A relation R is in Fifth Normal Form (5NF) and only if the following conditions are satisfied simultaneously,
    • R is already in 4NF.
    • It cannot be further non-loss decomposed.
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