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!
Dependency Preservation
It is obvious that the decomposition must be lossless so that we do not lose any information from the relation that is decomposed. Dependency preservation is another main requirement since a dependency is a constraint on the database. If each attributes appearing on the left and the right side of a dependency appear in the similar relation, then a dependency is considered to be preserved. Therefore, dependency preservation can be checked simply. Dependency preservation is important, because as stated previously, dependency is a constraint on a relation. Therefore, if a constraint is split over more than one relation (dependency is not preserved), the constraint would be complex to meet. We will not talk about this in more detail in this unit. You may refer to the more readings for more details. Though, let us state one basic point:
"A decomposition into 3NF is lossless and dependency preserving whereas a decomposition into BCNF is lossless but may or may not be dependency preserving."
Give the limitations of SQL authorization. The code for checking authorization becomes intermixed with the rest of the application code. Implementing authorization by applic
Define the step - Rearranging the Execution Order for Efficiency As we know that algorithm and data structure are closely related to one another, but data structure is conside
Explain degree of relation? Degree of a Relation - The degree or arity of a relation is the number of attributes n of its relation schema.
Explain the Difference between DROP and DELETE DELETE deletes one or more than one tuples of a particular relation from the database. DROP is employed to remove a table from th
What exactly is the concept of Functional Dependencies? And how do we associate this concept with the logic of Super-keys, Candidate Keys, etc? Given Relation R(A,B,C,D,E) with de
The result of the UNION operation between R1 and R2 is a relation that includes? The result of the operation between R1 and R2 includes all the tuples of R1 and R2 which have c
What is Multivalued Attribute? Multivalued Attribute - Multivalued attribute might have more than one value for an entity. For instance, PreviousDegrees of a STUDENT.
Define average latency time. The average latency time of the disk is one-half the time for a full rotation of the disk.
Differentiate between a Global and a Local temporary table? - A local temporary table exists only for the duration of a connection or if defined inside a compound statement, fo
If R1 and R2 are two union compatible relations or functions, then the result of R3 = R1 ∩R2 is the relation that contains all tuples that are in both the relations In other words,
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