Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Security: Data not needed by local applications is not stored at the site, therefore no unnecessary security violations may exist.
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?
Heap files (unordered file) Mostly these files are unordered files. It is the easiest and most basic type. These files having of randomly ordered records. The records will have
Explain the ISA relationship Answer: ISA relationship - ISA notation is employed in generalization/ specialization to depict relationship among lower and higer level entity s
Modular growth: In distributed environments, it is simple to expand. Latest sites can be added to the network without affecting the operations of other sites, as they are somewhat
what is Nested relational model? Explain with examples.
Let us now make the E-R diagram for the student database as per the explanation given in the previous section. We can also states the overall logical structure of a database usi
What are the Constituents of File? Also elaborates all the possible file operations? A file is organised logically as sequence of record. These records are mapped onto disk blo
entity relationship diagram for online examination system
A collection of a same kind of entities is known as an Entity Set or entity type. Example: For the COLLEGE database defines earlier objects of concern are Students, Faculty,
What is Disadvantages Of DBMS ? 1. Cost of Software and Hardware and Migration - A important disadvantage of the DBMS system is cost. 2. Reduced Response and Throughpu
What is assertion? Mention the forms available. An assertion is a predicate expressing a condition that we wish the database always to satisfy. Domain integrity constraints.
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd