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!
Relations create the database. They must satisfy various properties, like no duplicate tuples, no ordering of tuples, and atomic attributes, etc. Relations that satisfy these basic needs may still have some undesirable characteristics such as data redundancy, and anomalies.
What are these undesirable characteristics and how can we eliminate them from the database system? This part is an attempt to answer this question. Though, please note that most of these undesirable properties do not arise if the database modelling has been carried out very carefully using some method like the Entity-Relationship Model. It is still important to use the methods in this unit to check the database that has been acquired and ensure that no mistakes have been made in modeling.
The central thought in these discussions is the concept of Database integrity, the notion of functional dependency, which rely on understanding the semantics of the data and which deals with what information in a relation is dependent on what other information in the relation. Our prime objective in this section is to describe the concept of data integrity, functional dependence and then describes normal forms using functional dependencies and using other types of data dependencies.
OBJECTIVES
After reading this section you should be able to
Describe substring comparison in SQL. For the relation Person (name, address), write a SQL query that retrieves the names of people whose name starts along with ‘A' and address co
Question: (a) List four disadvantages of the File Processing System as compared to the Database Systems. (b) The integrity of a database is enforced by integrity rules. One
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 pictori
explain three types of internet risks to the consummers whent he business system is data dependent. how can we minimise these risks
The natural join is equal to which product? The natural join is equal to Combination of projection and Cartesian product
Explain What is Relation? A database relation is a predefined row or column format for storing information in a relational database. Relations are equal to tables.
What is the use of Union and intersection operation? Union: The result of this operation contains all tuples that are either in r1 or in r2 or in both r1 and r2.Duplicate tuple
A distributed transaction consists of subtransactions that execute at different sites and access local DBMSs at those sites. For example, a distributed transaction that transfers m
Explain the term - Handling Boundary Condition These are some circumstances that to be handled in any system initialization and termination. Describes how system is bro
Sequences Sequences: Automatically produce unique numbers Are sharable Are typically used to make a primary key value Replace application code Speed up 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