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."
What are the two statements regarding transaction? The two statements regarding transaction of the form are:- A) Begin transaction B) End transaction
Define query optimization. Query optimization refers to the process of search the lowest -cost method of evaluating a given query.
Why do so various organizations use MySQL? Advantages: Open source Highly efficient Offers a high scalability in terms of size and connectivity. Highly prote
What is B-Tree? A B-tree eliminates the redundant storage of search-key values .It permits search key values to appear only once.
INTRODUCTION Databases and database systems have become an essential part of our daily life. We encounter many activities that involve some interaction with a database almost
Differentiate between the object oriented decomposition and the structured decomposition? Process-oriented (structural) decomposition divides a complex process, function or tas
Define identify relationship? Identifying relationship: An identifying relationship means in which the child table cannot be uniquely recognize without the parent. For exampl
Convert the following ER - diagram (Entity Relationship Diagram) into a relational database (the primary keys are underlined): Ans: The relational database schema f
Draw an E_R Model for the following: An organization uses number of items of a equipment to generates goods. Each item is at one LOCATION, of one TYPE and has a DETAILED_DISCRI
Describe queries with complex types? The present extension of the SQL query language deal with the complex type Let us start with the simple example: Find the title and t
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