Normalization in DBMS

Normalization:

➺ It refers to the process of reducing data redundancy (repetition of the same data) and eliminating undesirable characteristics like Insertion, Update, and Deletion Anomalies(abnormal).
➺ It is the technique of organizing data in the database. It is a multiple series of step that sets the data into tabular form and minimize redundant data from the relational tables.
➺ It splits the larger table into the smaller table and links them in relationships.
➺ The main objective of normalization is to minimize and eliminate repetitive data.
➺ In this normal forms are used to minimize data redundancy in the database.

◆ Normal Forms in DBMS :-

➺ In this, an attribute can have only a single value (atomic value) in the column.
➺ 1NF doesn't allow multi-valued attributes in a single column.
➺ A table column name must be unique, not the same name.
➺ Every value stored in a column must be of the same domain in a table column.
➺ In 1NF data can be stored in any order that does not matter.

➺ It must be in Frist Normal Form(1NF).
➺ In relation, there should be no partial dependency.
➺ When no non-prime attribute is functionally dependent on any proper subset of candidate key relation.

➺It must be in Second Normal Form(2NF).
➺ In relation, there should be no transitive partial dependency.
➺ No non-prime attribute should not functionally dependent on other non-prime attributes.
➺ 3NF is used to reduce redundancy(duplication) of data and achieve data integrity in the table.
➺ The third Normal form is considered as Data Normalised.

➺It must be in Third Normal Form(3NF).
➺ BCNF was developed by Raymond F. Boyce and Edgar F. Codd.
➺ BCNF is an extension of the Third Normal Form (3NF) and is also known as the 3.5 Normal Form.
➺ A table is in BCNF if every functional dependency X->Y, X is the super key of the table.
➺ Every attribute of Right Hand Side(RHS), functional dependency depends on the super key on Left Hand Side.

➺It must be in Boyce-Codd Normal Form(BCNF).
➺ The table should not have multi-valued dependencies.
➺ For a dependency P → Q, if for a single value of P, multiple values of Q exist, then the relationship will be a multi-valued dependency.

➺ It must be in Fourth Normal Form(4NF).
➺ 5NF is also known as projection–join normal form (PJ/NF).
➺ The table should not have joined dependencies to the table.
➺ It cannot be further decomposed into any smaller table.

You might like this :-

○Codd's 12 Rules
○Data Independence in dbms
○RDBMS Introduction
○History of Computer