- It deals with the database design problem
- Normalization process concerns with the transformation of the conceptual schema (logical data structure) into computer representable form.
- It is a process of restricting data into tables; in order to ensure efficient & reliable storage & smooth retrieval of data.

**Database Schema**

**Formal Language**

**Need Of Normalization**

**Advantages of Normalization**

– It produces controlled redundancies to link tables

**Database Integrity**

**First Normal Form (1NF)**

**Primary key**. For example consider a table which is not in First normal form

- All Key Attributes defined
- No repeating groups in table
- All attributes dependent on Primary Key

**Second Normal Form (2NF)**

**Functional Dependence**R{Axis, Co-ordinate_1, Co-ordinate_2} are its attributes

(Co-ordinate_1) ——> (Axis) => Co-ordinate_1 is functionally dependent on Axis

(Co-ordinate_2) ——> (Axis) => Co-ordinate_2 is functionally dependent on Axis(Co-ordinate_1) non-dependent on (Co-ordinate_2)

__refers__

**Partial Dependency****to the dependency of a non-key (not assigned key constraints) on the portion of the composite-primary-key and not the whole primary key.**

Hence,

A relation R is in **2NF** if and only if (iif) it is in 1NF and every non-key attribute is** fully dependent **on the primary key.

**Third Normal Form (3NF)**

** Transitive Relation** ( If A->B and B->C then A->C)

A relation R is said is said to be in 3NF iif it is in 2NF and every non-key attribute is non-transitively dependent on the primary key.

**Boyce-Codd Normal Form (BCNF)**

** **A relation is in BCNF if it is in 3NF and all of its determinants(i.e the attributes upon which other attributes depend) are candidate keys.

To convert a 3NF into BCNF, decompose such that every determinant becomes a Candidate Key.

**Fourth Normal Form (4NF) **

Multi valueddependencies(MVD’s)expressa Multivalued dependencies (MVD s) express a

condition among tuples of a relation that

existswhentherelationistryingtorepresent exists when the relation is trying to represent

more than one many‐many relationship

**Trivial Multivalued Dependency**