Binary relationships, Database Management System

Assignment Help:

One-to-one relationship:

For every 1:1 relationship type R in the ER diagram including two entities E1 and E2 we take one of entities (say E1) preferably with total participation and add primary key attribute of one more entity E2 as a foreign key attribute in the table of entity (E1). We will also have all the simple attributes of relationship type R in E1 if any.

For instance, the DEPARTMENT relationship has been extended to contain head-Id and attribute of the relationship. Please note we will maintain information in this table of only present head and Date from which s/he is the head.

There is one Head_of 1:1 relationship among FACULTY and DEPARTMENT. We select DEPARTMENT entity having total participation and add primary key attribute ID of FACULTY entity as a foreign key in DEPARTMENT entity named as Head_ID. Now the DEPARTMENT table will be as follows:

DEPARTMENT

D_NO

D_NAME

Head_ID

Date-from

 

 

 

 

 

 

 

 


Related Discussions:- Binary relationships

How many types of data independence have, Types of data independence D...

Types of data independence Data independence can be classified into the following two types: Physical Data Independence: This means that for any change made in the physi

Give an example of operations from the state actions, Give an example of op...

Give an example of operations from the State Actions and Activities. For instance, in bank the activity verify account code and verify password

Write short notes on extension and intension, Write short notes on extensio...

Write short notes on extension and intension? In any data model, it is significant to distinguish among the description of the database and the database itself the description

Information infrasture, what benefit can a company gain by managing its own...

what benefit can a company gain by managing its own infrasture and services

Locking, define locking in simple language and decribed it

define locking in simple language and decribed it

Assignment SQL Management Server 2012, Have database built but having probl...

Have database built but having problems with some questions that go with the database

Update operations in dbms - insert operation, Update Operations and Dealing...

Update Operations and Dealing with Constraint Violations There are three basic operations to be executes on relations: Insertion Deletion Update The INSER

Function module and a normal abap/4 subroutine, What is the difference betw...

What is the difference between the function module and a normal ABAP/4 subroutine? In contrast to normal subroutines function modules have uniquely exact interface.  Declaring da

Database manager, Database Manager It is the interface among low-leve...

Database Manager It is the interface among low-level data, queries and application programs. Databases typically need a large amount of storage space. It is kept on disks, as

What are the benefits of decomposing a system, What are the benefits of dec...

What are the benefits of decomposing a system? The benefits of decomposing a system into subsystems are that after decomposition, each individual component become smaller and e

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

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!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd