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

Designing the fields in the data base, Designing the fields in the data bas...

Designing the fields in the data base The following are the considerations one has to remain in mind while designing the fields in the data base. Coding, compression, en

What is data independence, What is data independence? Data Independenc...

What is data independence? Data Independence: Techniques which permit data to be changed without affecting the applications in which procedure it. There are two types of data

Datawarehouse Case studies, I have been given 8 differebt data warehouseing...

I have been given 8 differebt data warehouseing failure case studies. I need to question 4 questions for each

Describe database state in details, Describe Database state in details? ...

Describe Database state in details? Database state: The actual data within the database at a particular moment in time is known as a database state.

Answer, what is database management system? & why it is required?

what is database management system? & why it is required?

What are the uses of the information in the data dictionary, What are the u...

What are the uses of the information in the Data dictionary? The following information is directly taken from the Data dictionary: Information on fields displayed with

The third normal form (3nf), The Third Normal Form (3NF) Even though, t...

The Third Normal Form (3NF) Even though, transforming a relation that is not in 2NF into a number of relations that are in 2NF take out many of the anomalies, it does not neces

Illustrate the definition of the classes and operation, The definition of t...

The definition of the classes and operation can often be adjusted to increase the amount of inheritance". Justify the above statement.   Adjustment of Inheritance The def

What are called index-sequential files, What are called index-sequential fi...

What are called index-sequential files? The files that are ordered sequentially with a primary index on the search key are known as index-sequential files

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