What is E-R model, Database Management System

E-R Model

This data model is based on real world that consists of basic objects named entities and of relationship among these objects. Entities are illustrated in a database by a set of attributes. An Entity - Relationship model is an abstract way to define a database. It generally starts with a relational database, which loads data in tables. Some of the data in these tables point to data in other tables - for instance, your entry in the database would point to various entries for each of the phone numbers that are yours. The ER model would define that you are an entity, and each phone number is an entity, and the relationship between the phone numbers and you is 'has a phone number'. Diagrams prepared to design these relationships and entities are called E-R diagrams or entity-relationship diagrams.

 

955_ER Model.png

Posted Date: 7/30/2012 1:46:07 AM | Location : United States







Related Discussions:- What is E-R model, Assignment Help, Ask Question on What is E-R model, Get Answer, Expert's Help, What is E-R model Discussions

Write discussion on What is E-R model
Your posts are moderated
Related Questions
What is the use of group by clause? Group by clause is used to be relevant aggregate functions to a set of tuples. The attributes given in the group by clause are used to shape

Define in which normalisation form if an attribute of a composite key is dependent on an attribute of other composite key. Ans: 3NF A relation is in 3 NF if an attribute of

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

Using Column aliases Example: To print column names as NAME and ANNUAL SALARY SELECT ENAME "NAME", SAL*12 "ANNUAL SALARY" FROM EMP;

Advantages of Observation  Methods: Bailey has pointed  out four  advantages of observation: 1. Superior in Data  Collection  on Non Verbal Behavior: When  a person  a opi

Give the reasons for allowing concurrency? The reasons for allowing concurrency is if the transactions run serially, a short transaction might have to wait for a preceding long

Write a Query that uses the UNION Operator 1. Use the Software Experts database to:   a. Display the first and the last name of all consultants who worked on any projects f

1. Will you advise that your organization uses open source software and why? 2. Why is it important for business managers to have a basic understanding of the software development

1. Explain different addressing modes of 8086 Explanation of all addressing modes 2. Write a sequence of instructions to exchange two register contents using stack

Define the Canonical cover Ans: A canonical cover F c for F is a set of dependencies like F logically implies all dependencies in F c , and F c logically entails all dependen