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."
WRITE SHORT NOTES ON INDEX STRUCTURE OF FILES? There are two basic parts of indices 1. Ordered indices 2. Hash indices Every technique must be evaluated on the bas
What is a recovery scheme? An integral part of a database system is a recovery scheme that can restore the database to the reliable state that existed before the failure.
DDL Compiler The DDL compiler changes the data definition statements (such as CREATE TABLE .... in SQL) into a set of tables having metadata tables. These tables have infor
How is concurrency identified? Concurrency in objects can be identified by the way they alter their state. Current objects can change their state independently. Aggregation imp
You are managing the following database system: • DBMS: Oracle 11g • OS: Sun Solaris • System architecture: Web-based application using ASP.Net • Purpose of Server: HR managem
(a) Provide the description of the following ODMG schema in the Object Definition Language (ODL). (b) Based on the above object database, write the following queries i
What are the comparison operator in SQL? Comparison operator in SQL are =, LIKE and BETWEEN
Surgeons identified by doctor ID (DOCID) operate on patients identified by patient ID (PATID) in operating theaters identified by room numbers (ROOMNO). Each surgeon can operate on
MySQL Database Merge Project Description: I have two databases, I need merge the data of one database into another Work to be done online right now. Payment can be done
Question: a) There are three concurrency problems, i.e. three types of potential mistake which could occur if concurrency control is not properly enforced in the database syst
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