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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?
Problem: A DBMS built for Online Transaction Processing (OLTP) is usually regarded as unsuitable for data warehousing. Each system is designed with a different set of requireme
What is the use of rename operation? Rename operation is used to rename both relations and an attributes. It uses the as clause, taking the form: Old-name as new-name.
Define tuple variable? Tuple variables are used for comparing two tuples in the same relation. The tuple variables are explained in the from clause by way of the as clause.
Describe the static hash file with buckets and chaining and show how insertion, deletion and modification of a record can be performed. In static hash file organization, the wo
What are the disadvantages of file-processing system? Ans: The Disadvantages of File-Processing System a. Data redundancy and inconsistency - Data redundancy means not nece
Attribute Preservation This is a easy and obvious necessity that includes preserving all the attributes that were there in the relation that is being decomposed.
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Parallelism of transaction execution: A transaction can be divided into various sub-queries that can operate on fragments in parallel. This enhances the degree of concurrency in t
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What is a trigger
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