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The concept of database normalization was first

introduced by Edgar Frank Codd in his paper A

Relational Model of Data for Large Shared Data

Banks,.

Database normalization is a process by which an

existing schema is modified to bring its

component tables into compliance with a series

of progressive normal forms

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The goal of database normalization is to ensure

that every non-key column in every table is

directly dependent on the key, the whole key

and nothing but the key and with this goal come

benefits in the form of reduced redundancies,

fewer anomalies, and improved efficiencies.

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First Normal Form (1NF)

The first normal form (1NF) sets the very crucial

rule to create the database :

1. There are no repeating or duplicate fields.

2. Each cell contains only a single value.

3. Each record is unique and identified by

primary key.

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The normalization process involves getting our

data to adjust in a progressive normal forms and

you cannot achieve the higher level of

normalization without satisfying the previous

levels. The First Normal Form asking the values in

each cell of a table must be atomic. The word

atomic describes that there should be no sets ofvalues in one particular cell.

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This table is not in first normal form because :

A. There are multiple fields in color lab.

B. Records are repeating (Duplicate records)or no primary key.

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Second Normal Form (2NF)

A table is said to be in 2NF if

A. It should meet all the requirements of thefirst normal form.B. It should remove subsets of data that applyto multiple rows of a table and place them in

separate tables.C. It create relationships between these newtables and their predecessors through the useof foreign keys.

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The First Normal form deals with the atomicity

whereas the Second Normal Form deals with the

relationship between the composite key columns

and non-key columns. To achieve the next

progressive level your table should satisfy the

requirement of First Normal Form then move

towards the Second Normal Form.

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Table is not in Second Normal Form because the

price and tax depends on the item, but not

color.

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ird Normal Form (1NF)The Third Normal Form has one more additional

requirement :

A. It should meet all the requirements of the second

normal form.B. It should remove columns that are not

dependent upon the primary key.

In the Third Normal Form all columns depend upon theprimary key. When one column depends upon the

other column, table break the rule and turns into the

dependency on the primary key.

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