Normalization 1nf 2nf 3nf Pdf Download: Principles and Examples of Database Normalization

One of the driving forces behind database normalization is to streamline data by reducing redundant data. Redundancy of data means there are multiple copies of the same information spread over multiple locations in the same database.

Normalization 1nf 2nf 3nf Pdf Download

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This article is an effort to provide fundamental details of database normalization. The concept of normalization is a vast subject and the scope of this article is to provide enough information to be able to understand the first three forms of database normalization.

There are a few rules for database normalization. Each rule is called a "normal form." If the first rule is observed, the database is said to be in "first normal form." If the first three rules are observed, the database is considered to be in "third normal form." Although other levels of normalization are possible, third normal form is considered the highest level necessary for most applications.

As with many formal rules and specifications, real world scenarios do not always allow for perfect compliance. In general, normalization requires additional tables and some customers find this cumbersome. If you decide to violate one of the first three rules of normalization, make sure that your application anticipates any problems that could occur, such as redundant data and inconsistent dependencies.

EXCEPTION: Adhering to the third normal form, while theoretically desirable, is not always practical. If you have a Customers table and you want to eliminate all possible interfield dependencies, you must create separate tables for cities, ZIP codes, sales representatives, customer classes, and any other factor that may be duplicated in multiple records. In theory, normalization is worth pursing. However, many small tables may degrade performance or exceed open file and memory capacities.

Normalization should be part of the database design process. However, it is difficult to separate the normalization process from the ER modelling process so the two techniques should be used concurrently.

During the normalization process of database design, make sure that proposed entities meet required normal form before table structures are created. Many real-world databases have been improperly designed or burdened with anomalies if improperly modified during the course of time. You may be asked to redesign and modify existing databases. This can be a large undertaking if the tables are not properly normalized.

As a database developer, we might often come across terms like normalization and denormalization of a database. Database normalization is a technique that helps to efficiently organize data in a given database. Essentially, it is a systematic approach to decompose a larger table into smaller tables that would help to get rid of data redundancy and other inserts/ update anomalies.

"Database normalization is the process of structuring a relational database in accordance with a series of so-called normal forms in order to reduce data redundancy and improve data integrity. It was first proposed by Edgar F. Codd as part of his relational model.

Database normalization is a database schema design technique, by which an existing schema is modified to minimize redundancy and dependency of data.if(typeof ez_ad_units!='undefined')ez_ad_units.push([[728,90],'w3schools_in-medrectangle-3','ezslot_0',108,'0','0']);__ez_fad_position('div-gpt-ad-w3schools_in-medrectangle-3-0');Normalization split a large table into smaller tables and define relationships between them to increases the clarity in organizing data.Some Facts About Database NormalizationThe words normalization and normal form refer to the structure of a database.Normalization was developed by IBM researcher E.F. Codd In the 1970s.Normalization increases clarity in organizing data in Databases.Normalization of a Database is achieved by following a set of rules called 'forms' in creating the database.Database Normalization RulesThe database normalization process is divided into following the normal form:First Normal Form (1NF)Second Normal Form (2NF)Third Normal Form (3NF)Boyce-Codd Normal Form (BCNF)Fourth Normal Form (4NF)Fifth Normal Form (5NF)First Normal Form (1NF)Each column is unique in 1NF.Example:Sample Employee table, it displays employees are working with multiple departments.EmployeeAgeDepartmentMelvin32Marketing, SalesEdward45Quality AssuranceAlex36Human ResourceEmployee table following 1NF:EmployeeAgeDepartmentMelvin32MarketingMelvin32SalesEdward45Quality AssuranceAlex36Human ResourceSecond Normal Form (2NF)The entity should be considered already in 1NF, and all attributes within the entity should depend solely on the unique identifier of the entity.

A relational database adheres to a greater or lesser extent to the 12 rules of an RDBMS drawn up by Codd. In developing a relational system, you use the process of normalization, which is verifying the relational nature of your data organization against the various degrees of normal form. We covered 1NF, 2NF, 3NF, and BCNF and showed how they help you verify the following:

You then looked at the power and risks of denormalization, the process by which you break the rules of normalization in order to improve application performance. This is something that requires experience in order to tailor its use appropriately for any given application, but it can prove invaluable in enhancing the user experience of your application. 2ff7e9595c