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!
Q. Describe how an ER schema can be represented by relation schemas and constraints arising from ER design can be mapped to constraints on a relation schema.
The entity relationship data model is based on a perception of a real world that consists of basic objects called entities and of relationships among these objects. An entity is thing or object in the real world that is distinguishable from other objects. For eg., each person is an entity and band accounts can be considered as entities. Entities are described in a database by set of attributes. For eg., the attributes account number and balance may describe one particular acconunt in a bank and they form attributes of the account entity set. An extra attribute customer id is used to uniquely identify customers. A relationship is an association among several entities. For eg., a depositor relationship associates a customer with each account that he has. The set of all entities of the same type and the set of all relationship of the same type are called entity set and relationship set respectively. The overall logical structure of a database can be expressed graphically by and ER diagram, which is buily up using : R ectangles - which represent entity sets Ellipses - which represent attributes Diamonds - which represent relationships Lines - which represent link attributes to entity sets. Each component is labelled with the entity or relationship that it represents. Constraints to which the contents of database must confirm. For eg., mapping cardinalities, which express the number of entities to which another entity can be asociated via a relationship set.
Define average seek time. The average seek time is the average of the seek times, calculated over a sequence of random requests.
What functions does a data dictionary perform? In a (DBMS)data management system, the principal functions performed by the data dictionary are Management of data defini
Emergence of Client Server Architecture Some of the pioneering work that was completed by some of the relational database vendors permitted the computing to be distributed on m
what is union compatable?
What are the advantages of object oriented databases in comparison with others? Why it is still not widely used? Object oriented designs are coherent, efficient and less prone
The database will enable college administrators the ability to track students initial major. This will help college officials decide how best to prepare students for their goals an
NEED FOR A DATABASE MANAGEMENT SYSTEM A Database is a structured, persistent collection of data of an organisation. The database management system (DBMS) manages the database o
Logical Operators Rules of Precedence: Order evaluated Operator 1 All comparison operators 2
Why is database design important?
For your chosen project, you need to identify the current problem that you wish your project to solve. Produce a Problem Statement. The Problem Statement should explain the purpo
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