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."
Ask q“A database will be made to store information about patients in a hospital. On arrival, each patient’s personal details (name, address, and telephone number) are recorded wher
What is a virtual table that draws its data from the result of an SQL SELECT statement? View is a virtual table that draws its data from the result of an SQL SELECT statement.
In problems 1 - 4, you are given the columns of a table, and a set of functional dependencies. Determine the normal form of this table. Remember that the normal form is the HIGHE
In which format database schema is written ? Data base schema is written in the DDL format.
how the string works as keyword?
Question (a) Differentiate between the following terms: (i) Distributed Database v/s Distributed Database management System (ii) Homogeneous Distributed Database v/s Hete
Locks: Serialisabilty is just a test whether a given interleaved schedule is ok or has a concurrency related trouble. Though, it does not make sure that the interleaved concurrent
What is data definition language? Explain it in detail? The SQL DDL allows specification of not only a set of relations, but also information after each relation, containing
Determine the OBJECTIVES of object design After passing through this unit, you should be able to: describe and apply concept of generalisation; understand and appl
Why DML is used for? DML is used to Manipulation and processing of database. DML is provided for manipulation & processing of database. (Data stored in the database is processed
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