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But how can we carry out fragmentation? Fragmentation may be carried out as per the following rules:
a) Completeness: This rule makes sure that there is no loss of data while fragmentation. If a relation is decomposed into fragments, then every data item must appear in at least single fragment.
b) Reconstruction: This rule makes sure preservation of functional dependencies. It should be possible to describe a relational operation that will reconstruct the relation from its fragments.
c) Disjointness: A data item that shows in a fragment should not show in any other fragment. Though, a typical fragmentation known as vertical fragmentation is an exception to this rule. In vertical fragmentation the primary key attributes must be repeated to permit reconstruction of original relation.
This rule makes sure minimization of data redundancy. What are the dissimilar types of fragmentation?
design a generalization specialization hierarchy for a motor vehicle sales company. the company sells motorcycles, passenger cars, vens and buses.
Desirable Properties Of Decomposition Decomposition is a process of dividing a relation into its projections that will not be disjoint. Please remind the Relational projection
You are to write a property management database program that allows a real estate agent to view, add, search, and save property listings. The program is to do the following: 1.
what is specialization?
Differentiate between natural join and outer join? Natural join is a binary operator which is written as (R * S) where as R and S are relations. The output of the natural join
Consider the relation schemas as follows. works (person name, company name, salary); lives (person name, street, city); located in(company name, city); managers (person name
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What is recovery management component? Ensuring durability is the responsibility of a software component of the base system known as the recovery management component.
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