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

What are the parts of sql language, What are the parts of SQL language? ...

What are the parts of SQL language? The SQL language has various parts: data - definitition language  Data manipulation language  View definition  Transaction contr

Which operation is used if we are interested certain columns, Which operati...

Which operation is used if we are interested in only certain columns of a table? PROJECTION operation is used if we are interested in only certain columns of a table.

What is key, What is key ? Key - A single attribute or a combination of...

What is key ? Key - A single attribute or a combination of two or more attributes of an entity set which is used to recognize one or more instances (rows) of the set (table) is

Write a short note on participation role, write a short note on participati...

write a short note on participation role? Participation role: roles are indicating in E-R diagram by labelling the lines that connect diamonds to rectangles.

What is the purpose of storage manager, What is the purpose of storage mana...

What is the purpose of storage manager? The storage manager is responsible for the following a) Interaction with the file manager b) Translation of DML commands in to low

Which operator is used to compare a value to a list literals, Which operato...

Which operator is used to compare a value to a list of literals values that have been specified? BETWEEN operator is used to compare a value to a list of literals values that h

Normalization, Introduction In large projects, we can have many different ...

Introduction In large projects, we can have many different companies working together. Generally, the project or contract is awarded to one company (Principal Contractor), which

Database schema, #Use the following database schema: 1) Patient—PatientID, ...

#Use the following database schema: 1) Patient—PatientID, Name, DOB 2) Doctor—DoctorID, Name, MedLicenseNumber, Phone 3) Medication—MedicationID, BrandName, GenericName 4) Prescrip

What is a candidate key, What is a candidate key? Minimal super keys ar...

What is a candidate key? Minimal super keys are known as candidate keys.

What are the two methods for dealing deadlock problem, What are the two met...

What are the two methods for dealing deadlock problem? The two procedures for dealing deadlock problem is deadlock detection and deadlock recovery.

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