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."
1) Define a job scheduling strategy that will meet business requirement of reporting availability by 6am CST for the following cubes? Show the job scheduling dependencies in a pict
Explain mechanism of nested queries? SQL gives a mechanism for nesting subqueries. A subquery is a select from where expression that is nested within one more query. A common u
Describe Parameteric end users? Parametric end users might be given update access, but are commonly not permitted to change the structure of data.
Process of implementing system design in dynamic models There are three essential approaches to implementing system design in dynamic models. These approaches are as below:
Project Description: This is a Customer Management project. Customer data is presented in a text file. The program can load this text data into its database columns. The data ma
Normal 0 false false false EN-IN X-NONE X-NONE
Define Cascading rollback The phenomenon where a single transaction failure leads to a series of transaction rollbacks is known as Cascading rollback.
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
Define access time. Access time is the time from when a read or write request is issued to when data transfer starts.
Strong entity set and weak entity set? Strong entity set and weak entity set: A strong entity set has a primary key. All tuples in the set are distinguishable through that key.
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