File Organization and its type

FILE DATA ORGANIZATION INTRODUCTION It is concern with how the data is stored in the database.It allows the designer to make decisions of how the database is to be implemented whereas the logical DB design is concerned with what data is stored in the database. It follows 2 steps:- 1.) Translate the global logical data model for target DBMS-It includes operations like designing of base relation...

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PHYSICAL DATA ORGANIZATION | PRIMARY INDEXES | DENSE INDEX |SPARSE INDEX

PRIMARY INDEXES- a.) A Primary index is an ordered file whose records are of fixed length with two fields. b.) The first field is of the same data type as the ordered key field called the primary key of the data file. c.) The second field is a pointer to a disk block(a block address) d.) There is one index entry (or index record) in the index file for each block in the data file. e.) Each...

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Introduction to normalization | NORMALIZATION

NORMALIZATION INTRODUCTION It is the process of decomposing or splitting the relation into relations with fewer attributes ,thereby minimizing the redundancy of data and  minimizing insertion,deletion and updation anomalies. It is a step by step reversible process of transforming and unnormalized relation into relations with simpler structure. Normalization works through a series...

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First Normal Form (1NF) | normalization and its types

FIRST NORMAL FORM(1NF) A relation is said to be in first normal form, if it satisfies the following rules. There are no duplicate rows i.e. all the primary key attributes are defined. There are no repeating groups in the table i.e. each rows and columns intersection contains one and only one value and not a set of vales. The first normal form does not allows a relations to contain nested relations. E.G-Consider...

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Functional Dependency (FD) | Database design

FUNCTIONAL DEPENDENCY(FD) An attribute of an relational 'R' is said to be functional dependent on attribute 'X' if and only if each 'X' value is associated with exactly one value of 'Y' at any given time. REPRESENTATION- Where 'X' is known as determinant and 'Y' is known as determined. EXAMPLE- HOW...

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Second Normal Form(2NF) | normalization and its type

SECOND NORMAL FORM(2NF) A relation is in 2NF if it holds these two conditions:- 1. The relation is in 1NF. 2. Every non -key attribute should be fully functional dependent on its primary key.If the primary key consists of a single attribute then the relation is in 2NF. EXAMPLE- Consider a relation....

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Third Normal Form (3NF) |Normalization and its type

THIRD NORMAL  FORM(3NF) INTRODUCTION-- A relation is said to be in third normal form(3NF) if both conditions hold simultaneously. 1.) The relation is in Second Normal Form(2NF) 2.) Non-key attributes of the relation should not be transitively dependent on the primary key. The main purpose...

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