What is normal form? Explain their types. Explain about loss-less join decomposition.

This answer is restricted. Please login to view the answer of this question.

Login Now

Normalization is the process of organizing the data in the database. Normalization is used to minimize the redundancy of a relation or set of relations. It is also used to eliminate undesirable characteristics like Insertion, Update, and Deletion Anomalies.

Normal forms are used to eliminate or reduce redundancy in database tables.

Normal Forms are divided into five types:

  1. First Normal Form
  2. Second Normal Form
  3. Third Normal Form
  4. BCNF
  5. Fourth Normal Form

1. First Normal Form:

For a table to be in the First Normal Form, it should follow the following 4 rules:

  1. It should only have single(atomic) valued attributes/columns.
  2. Values stored in a column should be of the same domain
  3. All the columns in a table should have unique names.
  4. And the order in which data is stored does not matter.

2. Second Normal Form:

For a table to be in the Second Normal Form,

  1. It should be in the First Normal form.
  2. And, it should not have Partial Dependency.

3. Third Normal Form:

A table is said to be in the Third Normal Form when,

  1. It is in the Second Normal form.
  2. And, it doesn’t have Transitive Dependency.

4. Boyce and Codd Normal Form:

Boyce and Codd’s Normal Form is a higher version of the Third Normal form. This form deals with a certain type of anomaly that is not handled by 3NF. A 3NF table that does not have multiple overlapping candidate keys is said to be in BCNF. For a table to be in BCNF, the following conditions must be satisfied:

  • R must be in the 3rd Normal Form
  • and, for each functional dependency ( X → Y ), X should be a super Key.

5. Fourth Normal Form:

A table is said to be in the Fourth Normal Form when,

  1. It is in the Boyce-Codd Normal Form.
  2. And, it doesn’t have Multi-Valued Dependency.
If you found any type of error on the answer then please mention on the comment or report an answer or submit your new answer.
Leave your Answer:

Click here to submit your answer.

Discussion
0 Comments
  Loading . . .